PLANT SCIENCE BULLETIN

December 1971 Vol. 17 No. 4

Bryophytes and Environmental Science   Harvey A. Miller   34
The Conference Devoted to the 50th Anniversary of Plant Photoperiodism   N. P. Aksenova   38
Editor's Notes   39

News and Announcements
Professional Opportunities   39
Pteriodology Section, B.S.A.   40
International Organization of Chemosystematics   40
Arnold Arboretum Centennial Program   40
Announcement of Darbaker Prize in Phycology for 1972   40
Organization for Tropical Studies Announces Graduate Course Schedules for 1972   40
Awards and Honors for Botanists, 1971   41
Personalia   41

Book Reviews
Evolution in the Higher Basidiomycetes, An International Symposium   Ronald H. Peterson, ed.   42
Biomathematics. Mathematical Topics in Population Genetics. Vol. 1.   Kojirna Ken-Ichi, ed.   43
World Catalog of Theses on the Pacific Islands.    Diane Dickson and Carol Dossor   44
Alkaloid-bearing Plants and their Contained Alkaloids, 1957-1968    J. J. Willaman and Hui-Lin Li   44

34

BRYOPHYTES AND ENVIRONMENTAL SCIENCE

Harvey A. Miller
Department of Biological Sciences
Florida Technological University
Orlando, Florida 32816

The role traditionally assigned to bryophytes in discussions of vegetation has been that of pioneer plants in successional series from bare rock to woodland or from the ashes of a forest fire to subsequent revegetation. The existence of these roles has been documented in a general way by many observers. In confirmation of this pioneering ability, Catherine Keever has shown experimentally that the moss Grimmia laecigata can become established even on polished granite. Bryophytes also were the plant pioneers on new lava flows of both Mt. Katmai, Alaska, and Mt. Kilauea, Hawaii.

Besides the pioneering role in develpment of edaphic conditions suitable for other plants, bryophytes are correctly credited with being soil binders on steep banks, water retainers, and favorable seed beds. The moisture retained by bryophytes over decaying logs enhances conditions for development of fungi and bacteria with resultant acceleration of nature's endless cycles of growth and decay. Peat mosses create conditions especially well suited for the preservation of pollen and spores which provide botanists with an indirect glimpse of past vegetational and climatic changes.

Closer familiarity with bryophytes reveals that they are a component in the terrestrial vegetation in all but the most arid regions of the world. Even in arid regions, some ephemeral bryophytes, as Riccia and Campos, occur following the infrequent rains. Because of their usual small size and narrow habitat requirements, bryophytes are often sensitive indicators of microclimates which may be quite different from the gross climates of the surrounding countryside. Thus, a species which is essentially tropical, as Hooheria acutifolia which is known from moist and thermally buffered sites in southern Ohio and Indiana, at nearly 40° N latitude, may be found in a microhabitat hundreds of miles from its "normal" range. The greatest abundance and diversity of bryovegetation is developed in the middle altitude cloud forests of the tropics and in the cool temperate coastal rainforests as found on the Olympic Peninsula, in New Zealand, and southern Chile. Here deep mats of bryophytes cover the ground, fallen logs, trunks and branches of trees, and occur on the surface of older leaves as well. Impressive masses of bryophytes, particularly peat mosses, develop in moist regions of higher latitudes even beyond the tree line. In brief, a limitless series of habitats is occupied by bryophytes within the melange of environmental factors ranging from desert to cloud-forest, tropical to polar, coastal strand to alpine, and deeply sheltered to exposed situations. Substrate texture, acidity, orientation, and chemical makeup also affect the composition of a bryophyte community. As a result, precise characterization of bryophytic vegetation combined with a good knowledge of the biology of the species involved can provide us indirectly with a number of significant environmental parameters.

Among the early attempts to summarize the relation-ships between bryophytes and the environment was the establishment and characterization of life forms summarized in the following key-like chart adapted from

Gams' chapter on Bryocenology in the Manual of Bryology (1932):

Main Life Forms

Floating in stagnant water   NATANTIA

On firm substratum   ADNATA
Submerged

Permanently   Nereidia

Periodically   Amphinereidia
Not submerged

On rocks   Epipetria

On trees   Epiphytia

On loose substatum   RADICANTIA

Annuals (or with a resting period)   Xerogeophytia
Perennials

Peat forming   Helophytia
Not peat forming.

On humus soil   Bryochamaephytia

On exposed mineral soil   Exochomophytia

The life forms are useful for gross characterization of some aspects of bryophytic vegetation but they are so broadly defined that environmental information which can be extrapolated is very limited.

In 1950, Gimingham and Robertson proposed a system of 'growth form types" in which the aspect of the matured colony or of some individual plants was correlated with light intensity and humidity as well as selected aspects of the chemical and physical attributes of the substrate. In addition, air-dry weight determinations were made to assess the possible demand on the habitat. For the sites studied in England, good correlation was found between growth form and habitat. More recently, Iwatsuki and Hattori (1968) have continued these studies on vertical distribution, degree of cover, and constancy of bryophyte cover on selected species of trees. As more precise data on tolerance limits of the indicator species and growth forms are developed, the value of these studies will increase.

Growth Forms of Epiphytic Bryophytes Description   Symbol

1. Cushions. Stems radiating

Large, over 5 cm in diameter   Cu

Small, not over 5 cm   cu

2. Turfs. Stems erect and parallel

Tall, over 2 cm high   Te

Short, under 2 cm   t

Open, shoots separate   To

Tall, from creeping "rhizomes"   Tc
Feather forms, "rhizomes" with

erect frondose branches   F

3. Canopy formers. Leafy branches above substrate

Dendroid forms   D

4. Mats. Dense interwoven horizontal mats

Rough short erect laterals abundant   Mr

Smooth, branches in plane of the axis   Ms
Thread-like, delicate open mats

or scattered strands   Mt

Thalloid mats, hepatics only   Th
Appressed, small closely attached and

not overgrowing, hepatics   Al)

5. Wefts. Stems loosely intertwined, often ascending

and luxuriant   W

6. Pendulous forms. Stems and

branches hanging free   P

The poorly developed to absent internal conducting system in bryophytes, the limited extent of the potentially absorptive rhizoid mass, and the usual physical delicacy ,i the plants combine to make them quickly and almost totally responsive to immediately surrounding environmental conditions. Accordingly, limits of tolerance to

35

microclimatic changes can be determined accurately and comparatively quickly when adequate controlled environment facilities are available. Few such studies have been undertaken hut the initial results are sufficiently provocative that environmentalists should consider taking careful note of bryophytes in their analyses.

Water relations:—Much of the water used by bryophytes is obtained by direct absorption or is trans-located by surface capillarity from the substrate. Internal conduction is very limited except in a few genera. Water holding capacity of bryophytes is considerable but the ability to retain moisture is dependent on the surrounding atmosphere. So-called xeromorphic mosses with thick cuticles. strongly papillose leaf cells, and hyaline tips have no greater water retentive ability than other species. Hydrophilic pectic compounds which might bind water are known only in trace amounts from a few bryophytes. There is no direct absorption of water from a moist atmosphere although water content may increase by capillarity from the substrate (Willis, 1964(. Numerous independent investigations on both mosses and hepatics indicate clearly that each species has an individual tolerance to relative humidity. Thus, an individual of a species can survive only within microhabitats where desiccation does not go below a critical level for a critical length of time. Hosokawa of al. (1964) in studies of light, compensation point, daily compensation period, photosynthetic rate, and water relations in corticolous epiphytes have shown that increased humidity resulted in increased photosynthesis. As these increases were especially great for those species which grow below the crown, Hosokawa suggested that "the ecological range of corticolous species is restricted at their lower limits by light and their upper limits by water."

Temperature:—Effects of temperature extremes are generally correlated with humidity or water content of the plants. Eva Clausen (1946) tested about fifty species and found that a temperature of 45° C was lethal for all but a few drought resistant species in less than turgescent condition. Heat tolerance dropped markedly for turgescent plants although most species could withstand :15° C even when fully moistened. Temperatures to -40° C were tolerated by some of the Danish populations with slightly better cold tolerance when plants were slightly desiccated. As with heat tolerance, drought resistant species fared best but not all were equally cold hardy. A moss has been reported to have survived treatment. in liquid air at about -190° C but the study should be

36

repeated with better controls than seem to have been present in the original study. Several species of bryophytes occur naturally in Antarctica and remain frozen for long periods with no apparent ill-effects, save desiccation of exposed tips as a result of high winds.

Edaphic factors:—In general, the same kinds of edaphic factors which affect growth and distribution of higher plants, i.e., pH, mineral nutrients present, texture, and structure affect bryophyte distributions. Among the bryophytes on mineral substrates, some are most successful on nutrient impoverished sites such as new lava and coastal dunes but others require comparatively abundant nutrient supplies as found among ashes. Organic substrates including rotting logs, bark, and leaves support characteristic floras but little is known about the extent of selectivity for substrate or the nature of the factors which influence that selectivity. For instance, I have observed that physically similar leaves of tropical trees with intermingled branches may support different floras or one species will be abundantly epiphyll adorned and the other will have naked leaves. The physical and chemical nature of the cuticle or bark seems to have a selective influence.

Mineral relations among terrestrial bryophytes have been difficult to assay because of the small size of the plants and their shallow penetration into substrate. The situation is somewhat complicated by seasonal variations in nutrient content of the mosses themselves. Streeter (1965) found potassium, sodium, calcium, and phosphorous contents of the moss Aerocladium cuspidatum varied with season, locality, and rainfall with the observation that potassium is the most important leachate accounting for the high K content of mats under trees in rainy months. Schacklette (1965, 1967) compared bryofloras from di 'erse mineral substrates in Alaska and determined the concentrations of various elements within the plants. The only obligate relations to minerals that he determined are those of Gymnocolea acutiloba to copper deposits and Grimmia maritima to salty sea spray. Among facultative relations, Racomitrium sudeticurn grew on ore containing 30 percent copper, Cephalonia bicuspidata tolerated ore with 13 percent lead and 34 per-cent zinc, and many other species seemed unaffected by relatively high concentration of elements including nickel, mercury, antimony, arsenic, chromium, and iron. Ashed bryophytes showed significant differences from higher plants in mineral content with only bryophytes showing niobium and scandium. Some 27 elements are ac-cumulated by bryophytes, especially Ba, Cu, Ph, Sr, and Zn, to concentrations normally toxic to other groups of plants. The presence of these relatively toxic minor elements in quantity may limit the palatibility for animals and susceptibility to fungal attack.

A few bryophytes are known to require exotic substrates as guano, dung, or animal carcasses. Some are facultative coprophiles, but Splachnaceae, especially Splachnum, require such media. Whitmire (1965) has suggested that the dung contains some principle which is required for sporophyte production and that the decline of the plants on old dung results from a lowering of the pH. Until Gressitt, et al. (1968) discovered bryophytes growing on the backs of large moss-forest weevils in New Guinea, no epizoic bryophytes were known. This epizoic flora seems to be comprised of species which are normally pioneers on young woody branches.

Although we know of no truly marine bryophytes, two genera of hepatics (Ric/la and Campos) are incredibly tolerant of alkali. Riella has a remarkably disjunct distribution which correlates with desert or near-desert ephemeral ponds. Apparently the spores germinate when the water is sufficiently fresh to indicate that the pond will last long enough for completion of the life cycle and the plants thrive even as the pond dries out and becomes quite brackish. Cai'ipo.s was discovered in 1955 encrusted with alkali along the salt pans of southeastern Australia and has since been discovered in a similar habitat in South Africa.

Light:—Radiant energy required for photosynthesis varies for bryophytes but the usual optimim range is 500 to 1000 foot candles for woodland species. Few data are available for optimum ranges for species which occur normally under light conditions different from those of tem-

perate woodlands. Light is known to be necessary for development of gernmae and protonemata of some mosses and for development of gametangia in several liverworts. A time/intensity relationship exists whereby a doubled in-tensity reduces development time by about half within the critical ranges. Seta elongation in Pellia is enhanced as light increases to about 20 foot candles. Water absorption in moss spores seems to be biphasic with the first phase being mechanical imbibition and the second a blue light regulated phase associated with protonemal development. Red light, by itself, has produced protonemal anomalies. A cumulative "light dose" effect which is independent of photoperiod is apparent in bud production on protonemata of Phvscomitriurn turbinatom (Nebel & Naylor, 1968). Other effects of light quality and intensity include modification of protoplasmic viscosity and plastid duplication,shape, size, and orientation. Beyond effects of red and blue wavelengths on a few species, we know little of the influence of other wavelengths or of the extent to which the responses are uniform through the bryophytes. Photoperiod effects have been established for both liver-worts and mosses in several developmental stages, and phytochrome has been isolated from two species of Mnium suggesting that bryophytes may also have a red/far red system.

Radiation:—Responses of bryophytes to ionizing radiation and X-ray emissions have shown sensitivity levels somewhat lower than those for higher plants. Some variation has been observed among bryophytes but generally mosses are most resistant and small leafy hepatics are the least resistant. Growing points with larger nuclei associated with meristematic activity are first to show radiation damage but, as all living cells in bryophytes are capable of dedifferentiation, destruction of actively meristematic sites only is not lethal. Somatic. cells of bryophytes have a very small nuclear volume which reduces the probability of a damaging or lethal impact. Seven distinct chromosomal races with five different chromosome numbers were developed by exposure of Brach ythecium rutabulum to high energy radiation (Moutschen, 1955) indicating that radiation damage is not always fatal. Even so, aberrant populations of bryophytes exposed to radiation sources in natural settings seem to be very rare, although damaged plants are evident for a time after exposure. Steere (1970) has noted that desiccated plants are more sensitive to irradiation than fully hydrated ones.

As might be expected from the tendency of many bryophytes to accumulate heavy metals, the elements associated with radioactive fallout also tend to be ac-cumulated. Cesium-137 has been found to be concentrated in mosses of a Cascades mountain bog; Strontium-90 has been found to be concentrated by bryophytes and lichens to the extent that it has been suggested that these plants may be used as indicators of radionuclide contamination; and other radioactive elements are concentrated over time with the result that bryophyte radioactivity continues to increase following fallout long after

37

radioactivity of higher plants has diminished toward normal.

Air Pollutants:—Although the initial report of the impact of air pollution on cryptogamic epiphytes was based on Nylander's observation on lichens in 1866, bryophytes are similarly affected and seem to hold as much promise as indicators of the presence and degree of pollution as lichens. Epiphytic bryophytes are sufficiently sensitive that bryovegetational differences have been observed between the windward and leeward sides of roads in the Netherlands. In central Florida, epiphytes in hardwood forests show damage, or species are absent, near highways cut through the woods with the roadside pollution effect extending a hundred yards or more from the edge of the right-of-way. Mosses and liverworts are less abundant and less diverse in cities than in distant countryside with the influence of major metropolitan areas extending far beyond the city limits in a pattern which reflects wind vectors. De Sloover and Le Blanc (1968) have proposed an Index of Atmospheric Pollution (IAP) based upon sensitivity of lichens to pollutants but it is clear that bryophytes, either independently or together with lichens, can be used in development of IAP. Bryophytes potentially can be used to determine isopolls indicating limits of comparable pollution around a source and to evaluate overall impact of continued pollution. Such information combined with transplant experiments (Broth), 1966) can be of value in enforcement of air pollution control laws where potential sources can be identified. Bryophytes and lichens are sensitive indicators of intermittent and long term pollution which might not be easily detected by instruments or human sensory organs.

Sulphur dioxide, a major component of pollution, caused observable damage under controlled conditions in about ten minutes in an atmospheric concentration of 120 parts per million. Lower concentrations over longer periods of time were also lethal with Radala and Orthatrichum being most sensitive. Mnium hornum, with a lower internal osmotic pressure than other species tested, is more resistant to SO., . All species were somewhat more tolerant of S02 when partially plasmolyzed. The initial, and apparently irreversible, reaction converts chlorophyll a into phaeophytin a followed by plasmolysis and death.

Man is clearly responsible for concentrated pockets of air pollution which produce haze or smog but there is natural pollution as well. Rasmussen et al. (1968) describe biological sources of air pollution involving light hydrocarbons and monoterpenes which could be photochemically sensitized in the laboratory to produce a blue haze as that often observed over closed tropical vegetation. Epiphyte covered palm leaves were field tested in Panama for organic volatiles. The epiphytes with a "gluey to anise-like aroma" were left on the living fronds for the first profile of volatiles by gas chromatography. Volatiles were as much as ten times those of other leaves previously tested. After removal of surface epiphylls by water washing with mechanical assistance, the volatiles produced were reduced significantly. The aroma described prior to cleaning suggest strongly that hepatics in the genera Drepanolejeunea and possibly Leptolejeunea were responsible for the odor and the terpenes. Rasmussen has indicated informally that vouchers were not kept (regretably!) but acknowledged that herbarium specimens of these genera looked similar to their material. Are some, or all, bryophytes producing the light-convertible, highly volatile, terpenes which haze the atmosphere? For now, that ecological question and uncounted hundreds of others remain unanswered.

The preceding paragraphs summarize something of bryophyte ecology and environmental physiology but the coverage is far from complete. We have attempted to demonstrate that inclusion of mosses and liverworts in environmental studies may yield unexpected insights into ecosystem dynamics. If this review stimulates further idterest, or suggests an approach for possible resolution of a difficult problem, then its purpose will be well served.

Literature Cited

Brodo, I. 1966. Lichen growth and cities: a study on Long Island, New York. Bryologist 69: 427-449.

Clausen, Eva. 1964. The tolerance of hepatics to desiccation and temperature. Bryologist 67: 411-417.

De Sloover, J. and F. LeBlanc. 1968. Mapping of atmospheric pollution on the basis of lichen sensitivity. In Misra, R. and B. Gopal (eds.) Proc. Symp. Recent Adv. Trop. Ecol. pp. 42-56. Banaras Hindu Univ. Varanasi, India.

Gams, H. 1932. Bryo-cenology (moss-societies). In Verdoorn, F. (ed.) Manual of Bryology. pp. 323-366. Nijhoff. The Hague.

Gimingham, C. H. and E. J. Robertson. 1950. Preliminary investigations on the structure of bryophytic communities. Trans. British Bryol. Soc. 1: 330-344.

Gressitt, J. L., G. A. Samuelson, and D. H. Vitt. 1968. Moss growing on living Papuan moss-forest weevils. Nature 217: 765-767.

Hosokawa, T., N. Odami, and H. Tagawa. 1964. Causality of the distribution of corticolous species in forests with special reference to the physio-ecological approach. Bryologist 67: 396-411.

Iwatsuki, Z. 1960. The epiphytic bryophytic communities in Japan. Journ. Hattori Bot. Lab. 22: 159-350.
   , and S. Hattori. 1968. Studies on the
epiphytic moss flora of Japan, 18. The epiphytic bryophyte communities in the broad-leaved evergreen forests of Hanaze, southern Kyushu. Journ. Hattori Hot. Lab. 31: 189-197.

Moutschen, J. 1955. L'obtention d'une serie de mutants aneuploides chez la mousse Brachythecium rutabulum Schpr. Soc. Belg. Biol. 1955: 591-593.

Nebel, B. J. and A. W. Naylor. 1968. Light, temperature and carbohydrate requirements for shoot-bud initiation from protonemata in the moss Physcomitrium turbinatum. Amer. Journ. Bot. 55: 38-44.

Rasmussen, R. A., R. S. Hutton, and R. J. Garner. 1968. Factors in establishing microbial populations on biologically inert surfaces. Pp. 79-98. Proc. 1st Internat. Biodeterioration symp., Southampton, 1968. Else-vier Publ. Co.

Schacklette, H. T. 1965. Bryophytes associated with mineral deposits and solutions in Alaska. U. S. Geol. Surv. Bull. 1198-C: 1-18.

   , 1967. Element content of bryophytes.
U. S. Geol. Surv. Bull. 1198-D: 1-21.

Steere, W. C. 1970. Bryophyte studies on the irradiated and control sites in the rainforest at El Verde. Chpt. D-11, 213-225. In Odum, H. T. (ed.) A tropical rainforest . U. S. Atomic Energy Commission, TID-24270

(PRNC-138), Oak Ridge.

Streeter, D. T. 1965. Seasonal variations in the nutrient content of Acrocladium cuspidatum (Hedw.) Lindb. Trans. British Bryol. Soc. 4: 818-827.

Whitmire, R. S. 1965.. Ecological observations on Splachnum ampullaceum. Bryologist 68: 342-343.

Willis, A. J. 1964. Investigations on the physiological ecology of Tortula ruraliformis. Trans. British Bryol. Soc. 4:668-683.

38

THE CONFERENCE
DEVOTED TO THE 50th
ANNIVERSARY OF PLANT
PHOTOPERIODISM

P. . Aksenota

The K. A. Tintirvazcr' Institute of
Plant Physiology of the

Academy of Sciences of the USSR
(Moscow')

The discovery of photoperiodism was announced in 1920 when the work of Garner and Allard was published. Some evidence on the effect of a daylength on flowering can be found earlier, e.g. in the works of Tournoi ( 1921) and Klebs ( 1918); however, a systematic and profound study on the effect of photoperiods on flowering, growth and ntorphogenesis of various plants was first undertaken by Garner and Allard who defined the response of plants to the relative length of day and night by the term "photoperiodism" and delineated the main photoperiodic groups of short-day, long-day and day-neutral plants.

'1'lre Conference, devoted to the 50th annivers;try of the discovery of plant photoperiodism and organized on the initiative of K. A. Timirvazev Institute of Plant Physiology of the USSR Academy of Sciences, was held on the 17th of November, 1970. About :300 representatives from 19 biological institutions and organizations of' Moscow, Leningrad, Novosibirsk, L•kutsk, Ufa, Saratov, Stavropol, Rostov, etc. participated in the conference.

In the opening speech, Academician A. L. Kursanov pointed out that the discovery of photoperiodism was an important event in biology initiating a very large number of investigations in many countries and being very significant for plant science. Then he briefly described the main trends in the research of photoperiodism represented in the titles and theses of the four speakers. In conclusion, Academician Kursanov emphasized that the main discoveries of molecular genetics and general molecular biology, applied for the investigation of regularities governing plant. ontogenesis, open broad prospects for future understanding of primary phenomena determining the transition of plant organisms from vegetative growth to reproduction.

In his report "Photoperiodism and Environmental Factors", Corresponding Member of' the Academy of Agricultural Sciences ( VASKHNIL) V. I. Razunury interpreted the role of the photoperiodic response for the geographic distribution of wild and cultivated plants as well as for the establishment of a culturing time for various species and varieties of agricultural plants. In particular, he analysed the behaviour of :37 wheat cultures from Australia and 16 cultures from Mexico grown under conditions of the daylength and temperature of Leningrad. A particular emphasis in the report was laid on the regularities governing the interaction of' temperature and photoperiodic factors in the regulation of' plant growth. It was concluded that temperature conditions produce a considerable effect on the plant photoperiodic response.

Corresponding Member of the Academy of Agricultural Sciences (VASKHNIL) B. S. Moshkov regarded photoperiodism as a biological phenomenon of a very general nature related to the inherent rhythmicity of physiological processes interacting with the daily rhythms of radiant energy. In this connection, the photoperiodic response of' flowering is one of the special cases of photoperiodism. The role of' photoperiodism for the plant life and for agricultural practice was demonstrated on the

examples of photoperiodic response of growth and dormancy, vegetative growth, accumulation of organic mat-ter, resistance to unfavorable environmental factors, immunity to diseases, etc

The speaker paid much attention to the comparison of the flowering photoperiodic response and the photoperiodic response of vegetative growth in Kalcar. throe. He discussed in great. detail the processes in plant leaves as organ-receptors of the photoperiodic effect and mentioned the relation of the primary processes of photoperiodism to the presence of carbon dioxide in surrounding atmosphere.

Academician M. Kh. Chailakhyan discussed plant photoperiodism with respect to the hormonal conception of flowering and its two-phase character. The transition to flowering is supposed to consist of two phases: stem formation and flower formation. Stem formation in long-day species is the phase limiting flowering under conditions of unfavorable photoperiod, and this critical phase is overcome by gibberellins which are intensively produced under long-day conditions. The critical phase in short-day species is the formation of' flowers, and this phase is overcome lry anthesins which are actively synthetized under short-day conditions. The speaker presented new data obtained by grafting long-short-day species of Brvophyllum which demonstrated the participation of different hormones in the regulation of flowering in this plant.

The interaction of extraneous factors and intracellular factors of dflowering was also analysed. Genetic information on flowering in neutral plants is realized irrespective of' the day length (the autonomous regulation of flowering), while its direct realization in species adapted to the day length is controlled by environmentphotoperiod of a certain duration tthe photoperiodic regulation of flowering). The correlation between the autonomous and photoperiodic regulation of two flowering phases is considered in plants belonging to different photoperiodic groups.

Changes of Address: Notify the Treasurer of the Botanical Society of America, Inc., Dr. Theodore Delevoryas, Department of Biology, Yale University, New Haven, Connecticut.

Subscriptions for libraries and persons not members of the Botanical Society of America are obtainable at the rate of $4.00 a year. Send orders with checks payable to "Botanical Society of America, Inc." to the Treasurer.

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39

Professor V. V. Skripchinsky discussed the laws of evolution of photoperiodism. Since the pattern of evolution can be based on the knowledge of present processes, the speaker analyzed the data of geography, ecology, physiology and genetics of plants, and their taxonomy and evolution.

Photoperiodism is shown to be a useful adaptive reaction of plants which helps them survive unfavorable times of the year; therefore, evolution of angiospermous plants is closely connected to photoperiodism. Geographical distribution of plant photoperiodical types depends on the latitude, temperature and the altitude above sea level, hence, short-day species are mainly distributed in the tropical zone at low altitudes and long-day species at high altitudes.

There was a discussion of the variability of photoperiodic response among angiospermous plants belonging to different families, genera and species. Evolution of photoperiodism was shown to be due not to changes taking place at the level of large taxons, but rather to the processes of variability and selection within the same species and population. No essential obstacles were found to evolutionary changes of the type of photoperiodic response, for the transition between the short-day, long-day, and neutral types of response, and for their realization in the course of evolution. Elementary processes of hereditary change of photoperiodic response depend on various mutations, and further evolution of photoperiodism is due to selection related to specific conditions of the medium.

The data of paleogeography, as well as the data on photoperiodism in algae, mosses, ferns and gymnosperms suggest that ancient lepidophytes and psilophytes belonged to the non-photoperiodic type (plants primarily neutral to the day length), while Devonian plants were typical short-day and then long-day species.

Editor's Notes

Many academic botanists today want to show that plant science and especially their own research are important to modern society. Our lead article in this issue is an example of this interest. Perhaps it is necessary since our problem-oriented society appears to demand material justification for everything not connected with its own leisure-time pursuits. A few years ago it would have been difficult to imagine a more esoteric branch of botany than bryology, even though mosses have been known to be sensitive phytometers of air pollution for a long time. The bryologist has become relevant, just as the rest of us must!

Another article, appearing earlier in the pages of PSB, unfairly suggested that many botanists were themselves asleep to the importance of plant science in the modern world. My own observations tell me very much the opposite. It is not necessary here to point out in detail the leadership assumed by plant scientists in adapting new learning techniques and curricula in the presentation of the botanical sciences; or the important role botanists have taken in the actions of national biological commit-tees including those studying social issues; or the many who are noted for their imaginative and productive careers in research and in academic administration. There is an increasing proliferation of botany courses especially for non-majors in response to the growing interest in plants by ecology-minded undergraduates. To borrow a phrase, botanists have been involved in a green revolution for the past several years. The relative importance of plant science in biological curricula or in research programs is not an issue in any modern institution of higher learning.

News & Announcements

Professional Opportunities

The University of Idaho, Department of Biological Sciences, announces that applications are now being received for plant ecologist, at the rank of Assistant Professor, with salary of $9,750-$10,750, beginning September 1, 1972. The candidate must have the Ph.D. and post-doctoral experience is desirable. Application should be made to Doyle E. Anderegg, Department of Biological Sciences, University of Idaho, Moscow, Idaho, 83843.

Winthrop College, Department of Biology, is soliciting applications for a bacteriologist at the rank of Instructor, beginning August 1972. The candidate must have the master's degree, and preference will be given to a person who plans to return to graduate school in about two years. Application should be made to Dr. John A. Freeman, Chairman, Biology Department, Winthrop College, Rock Hill, South Carolina, 29730.

Applications are now being solicited from candidates for the position of Head of the Department of Forestry and Wildlife Management, University of Massachusetts. The position is that of senior departmental executive officer, reporting to the Dean of the College of Agriculture. Salary will be commensurate with the responsibilities and the applicant's qualifications, and will be based upon a 12-month appointment. Interested persons are urged to forward a personal resume, list of publications, and names of at least three references to Dr. Charles F. Cole, Chairman, Search Committee, Department of Forestry and Wildlife Management, Holdsworth Natural Resources Center, University of Massachusetts, Amherst, Massachusetts, 01002.

Pteridology Section, B.S.A.

The newly formed Pteridology Section of the Botanical Society of America was organized at the joint Canadian Botanical Society-Botanical Society of America meetings at Edmonton in June. The By-laws have been approved by interested members and the following officers were elected: Chairman: David Bierhorst; Secretary-Treasurer: Edward Klekowski; Representative to Editorial Board, American Journal of Botany: Rolla M. Tryon.

The concentration of leadership in Massachusetts is a fortuitous circumstance and all people interested in Pteridology from all parts of the country are urged to indicate their interest by joining the Pteridology Section of the BSA. Membership in the latter organization is, of course, necessary.

Send name and address to the Secretary-Treasurer (E. Klekowski) along with one dollar in annual dues, care of the Department of Botany, University of Massachusetts, Amherst, Mass.

International Organization
of Chemosystematics

As has been discussed in Chemical Plant Taxonomy Newsletters, the rapid expansion of the chemical approach to systematic problems in biology has brought about a number of specialized problems unique to

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chemosystematics which could be greatly aided through international cooperation. As a result, a joint Inter-national Union of Pure and Applied Chemistry (IUPAC)—International Association of Plant Taxonomy (IAPT) ad hoc Committee on Chemotaxonomy has been formed to look into all aspects of the organization of international collaboration in chemosystematics. The Committee consists of Dr W. F. Grant (IAPT)—Chairman, Dr T. Swain (IUPAC)—Secretary, Dr J. B. Harborne (IUPAC), Dr. A. Love (IAPT), Dr. T. J Mabry (IUPAC) and Dr B. L. Turner (IAPT).

The Committee solicits comments from interested per-sons in all fields of biological sciences as well as those in biochemistry, chemistry, and the pharmaceutical sciences. These may be sent to the Chairman or the Secretary: Dr. W. F. Grant, Chairman, Joint IUPAC—IAPT Committee on Chemotaxonomy, Genetics Laboratory, MacDonald Campus of McGill University, Ste. Anne de Bellevue 800, Quebec, Canada; Dr. T. Swain, Secretary, Joint IUPAC—IAPT Committee on Chemotaxonomy, Royal Botanic Gardens, Kew, Richmond, Surrey, England.

Arnold Arboretum Centennial Program

A Centennial Celebration for the Arnold Arboretum of Harvard University has been set for May 21-May 28, 1972. The event will feature lectures by distinguished visitors and scientific symposium on botanical and horticultural themes. A formal banquet, the opening of an exhibit of rare books at the Houghton Library, and an evening concert of the Boston Pops Orchestra will highlight events of a more social nature. An afternoon lecture series is designed especially for Friends of the Arnold Arboretum. For representatives of botanical gardens and arboreta there will be bus tours to areas of exceptional botanical and horticultural interest in Massachusetts. Further information can be obtained by writing to Dr. Richard A. Howard, Director, Arnold Arboretum, The Arborway, Jamaica Plain, Mass. 02130.

Announcement of Darbaker Prize In Phycology For 1972

The committee on the Darbaker Prize of the Botanical Society of America will accept nominations for an award to be announced at the annual meeting of the Society at the University of Minnesota, Minneapolis, Minnesota, in 1972. Under the terms of the bequest, the award is to be made for meritorious work in the study of microscopical algae. The Committee will base its judgment primarily on the papers published by the nominee during the last two full calendar years previous to the closing date for nominations. At present, the award will be limited to residents of North America. Only papers published in the English language will be considered. The value of the Prize for 1972 will depend on the income from the trust fund but is expected to be about $325. Nominations for the 1972 award accompanied by a statement of the merits of the case and by reprints of the publications supporting the candidacy must he received by March 1, 1972, by the Chairman of the Committee, Dr. Isabella A. Abbott, Hopkins Marine Station, Stanford University, Pacific Grove, California 93950.

Organization For

Tropical Studies Announces Graduate Course

Schedules for 1972

During its tenth consecutive year of conducting research and training programs in the American tropics, OTS in 1972 will offer four graduate courses. Three of the courses will be scheduled in Ecology and Advanced Biology, while the fourth will be offered in Geography.

In the winter semester, January :31 to March 25, the ecology course will consist of Tropical Biology: An Ecological Approach. This will be open to 20 participants and will be conducted at the regular field sites in Costa Rica which demonstrates the whole range of tropical environmental conditions existing from sea-level to the highest altitudes in the central mountain ranges.

In the spring semester, April 17 to May 27, OTS will offer a new course in advanced biology entitled The Pine Forests of Central America. The extensive pine forests of Western North America extend south into the highlands of Central America to northern Nicaragua. The course will be coordinated by Dr Gordon H. Orions, Professor of Zoology, University of Washington, assisted by a staff of full-term and visiting scientists. The training will be con-ducted entirely in Guatemala and Honduras.

In the summer semester from July 3 to August 26, two courses will be offered in Costa Rica. One of the courses will be a repeat of Tropical Biology,- An Ecological Approach, while the second will be a course in Geography, a study of Man's Impact on Tropical Ecosystems in Costa Rica, Past and Present. This course is designed to give the student field experience in problems associated with man's interaction with tropical ecosystems. The course will be co-coordinated by Dr. Robert C. West of Louisiana Slate University and Dr Jonathan D. Sauer of the University of California at Los Angeles. They will be assisted by a staff of two visiting scientists.

Application forms may be obtained from the North American Office of the OTS at 5900 S.W. 73rd Street, South Miami, Florida, 33143. The deadlines for filing applications for each semester are as follows; Spring: January 15, 1972; Summer: April 1, 1972.

Awards and Honors For Botanists, 1971

During the Annual Dinner for All Botanists held on the campus of the University of Alberta, Edmonton, June 23, 1971, President Starr announced the Merit Awards for 1971, the winners of the Darbarker Prize and the Cooley Prize, and the new corresponding members of the Botanical Society of America. The annual Merit Awards were presented to four distinguished recipients, as follows:

To Murray F. Buell of Rutgers University

"eminent ecologist, teacher, and editor; his research on ecological processes in eastern North America has led to an understanding and public awareness of man's role in changing natural ecosystems."

To Verne Grant of the University of Texas

"evolutionist and student of the biology of flowers, especially of the phlox family. His works on speciation and adaptation in the higher plants are models of clarity and erudition."

To Ruth Patrick of the Academy of Natural Sciences in Philadelphia

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"a gifted teacher and scholar with a consuming curiosity, she brings out the best in both scholars and students by her unique ability to generate excitement over intellectual ideas. Best known for her work on the systematics of' diatoms, she has also been deeply concerned with the pollution of streams, rivers and bays, and has used her knowledge of diatom taxonomy and ecology — and her eloquence — to convince industries and cities of their responsibility in this area."

To A, Erling Porsild of the National Museum of Canada

"famous for his share in the Great Reindeer Trek; intrepid arctic explorer and distinguished student of the flora of Canada; and a Canadian diplomat as well."

The Darbaker Prize in Phycology was presented to: Richard W. Eppley of the Institute of Marine Resources in LaJolla,

"for his original and new approaches to the understanding of phytoplankton ecology."

and,

To Michael J Wynne of the University of Texas,

"for outstanding contributions in the taxonomy and morphology of marine algae, particularly the Rhodophyta and Phaeophyta,"

The George R. Cooley Prize for the best paper presented at the annual meeting of the American Society of Plant Taxonomists, was awarded to Dr. Beryl Simpson Vuilleumier, Harvard University, for her paper entitled "Multiple modes of speciation in the Pereziae of southern South America."

The New Corresponding Members are as follows: Gee Arbo Hoeg, professor emeritus of botany and retired director of the Botanical Museum and Garden at the University of Oslo, is the dean of Scandinavian paleobotany and one of the foremost authorities in the world on early Paleozoic floras. His major works include a classic study of the Downtonian and Devonian flora of Spitsbergen, a detailed consideration of the Glossopteris flora of the Belgian Congo, and, most recently, a world-wide treatment of the perplexing Psilophyta. His breadth of interest and knowledge has been demonstrated by activities in the fields of ethnobotany, particularly folk medicine, and dendrochronology. His sterling character, most kindly personality, and genuinely helpful attitude have endeared him to his colleagues and to countless students.

Rudolfo Pichi-Senn ulli, presently Professor of Botany and Director of the Botanical Institute at the University of Genoa (Genova), is a well known authority on the classification and relationships of the ferns. Additionally, he has made invaluable contributions to pteridophyte systematics as a bibliographer and as a member of numerous international nomenclature committees. As director and editor of the "Adumbratio Florae Aethiopicae" he has devoted part of his energies to floristic and ecological studies on the plants of eastern Africa, especially Ethiopia. His versatility and scientific accomplishments, together with great personal charm, have gained him renown and the respect and affection of' the botanical community.

Armen Leonouich Takhtajan, chairman of the Department of' Higher Plants of the Komarov Botanical Institute, is a leading Soviet plant taxonomist and morphologist and an internationally pre-eminent authority on the classification, origin, and historical phytogeography of flowering plants. Fortunate, indeed, are English-speaking scientists now to have at hand his book Flowering Plants: Origin and Dispersal, an extensively revised translation of his earlier Russian work Origins of Angiospermous Plants to which much new material has been added. His outstanding accomplishments, extensive international travels, and warm personality have won him admiration and affection throughout the botanical world.

Personalia

Two new faculty members joining the Department of Botany of The University of Tennessee, Knoxville in September 1971 were Drs. Otto J. Schwarz and Mark W. Bierner. Dr. Schwarz has completed a postdoctoral traineeship in the Biology Division of Oak Ridge National Laboratory after receiving his Ph.D. in Plant Physiology from North Carolina State University. Dr. Schwarz will teach plant physiology and continue his research in the biochemical and developmental aspects of enzyme regulation in plants. Dr. Bierner received his Ph.D. from The University of Texas and will teach in the plant taxonomy program and carry on his biochemical and morphological systematic studies on several genera in the Compositae.

The Society of the Sigma Xi announced today through the chairman of its grants-in-aid of research committee an award to Di: H. Lloyd Mogensen of Northern Arizona University.

This award has been made to Dr. Mogensen to assist him in his study of "The ultrastructure of fertilization in Quercu.s gambelii: Normal vs. abortive zygotes."

Dr. Richard S. Furr has been named assistant professor of biological sciences at Lake Superior State College. Dr. Furr received his bachelor of arts degree in biology from Pfeiffer College, Misenheimer, N. C., his master from North Carolina State U. and his doctorate in botany from the University of Tennessee.

Book Reviews

PETERSEN, RONALD H. (Editor), Evolution in the Higher Basidiomycetes, an International Symposium. The University of Tennessee Press, Knoxville, Tennessee. 1971. i-x, 562 pp. 13 black & white plates.

$20.00.

If I may quote from the preface of Evolution in the higher Basidiomycetes: "Perhaps no higher praise can be given a scholar and his work than for him to be honored by eminent specialists of his own discipline. Such a tribute was paid to Lexemuel Ray Hesler in August, 1968, when, on the occasion of his eightieth birth year, mycologists from Holland, Great Britain, France, Mexico, Canada, Czechoslovakia, and from many areas of the United States assembled on The University of Tennessee campus in Knoxville to participate in the symposium on which this volume is based. The meeting honoring Dr. Hesler proved to be highly appropriate, for the papers presented—and indeed the discussions— reflected a liveliness of intellect and enthusiasm for learning that have characterized the honoree throughout his long career".

Ron Petersen is to be congratulated for a splendid job of organizing this symposium, and for the excellent editorial work that went into assembling, organizing, and preparing for publication the papers and discussions that make up this book. Biologists will find some, or perhaps most, of the papers of great interest. Mycologists will be impressed not only with the titles of papers, but more so

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with the list of participants in the symposium.

The book is divided into three sections. Part I, the Introductory Address, is provided by M. A. Donk, the eminent mycologist from the Rijksherbarium in Leiden, Holland. He discusses progress in the study of the classification of higher Basidiomycetes. He attempts to show the process of transmutation of the Friesian classification, founded mainly on hymenial configuration, into a more natural system based upon cultural, cytological, developmental, as well as morphological features. Although he draws heavily on his years of research on the Aphyllophorales, his numerous comments on other groups reveals his keen interest in and vast knowledge of many phases of mycology.

Part II contains a series of papers on "Supportive Characters in Systematics". Varro E. Tyler, Jr., (School of Pharmacy, Purdue University) stimulates much interest in his review of "Chemotaxonomy in the Basidiomycetes". His discussion l of biosynthesis of various chemicals within plants is helpful in understancling the utility and limitations of chemotaxonomy in fleshy fungi. He summarizes the data obtained thusfar on several genera of Agaricacales, Aphyllophorales, and Gasteromycetes. In their paper on "The Pigments of Basidiomycetes: Their Chemotaxonomic Interest", Noel Arpin and Jean-Louis Fiasson, University of Lyon, after a lengthy discussion of pigment systems and their evolution in fungi, imply that perhaps pigment. pathways will enable us to tell which way the arrow is pointing in many groups. Paul L. Lentz (Plant Industry Station in Beltsville, Md.), analyzes the use of modified byphae as a tool in taxonomy research in the higher basidiomycetes. He concludes that the term "modified hyphae" is hardly definitive, and that comparisons are needed between such hyphae in the heterobasidiomycetes and monobasidiomycetes before we can consider their use as taxonomic tools. In his paper on "Nuclear Behavior in the Mycelium and the Evolution of the Basidiomycetes", Jacques Boidin, (Universite de Lyon, France), discusses the correlations of nuclear behavior, clamp connections, and spore nuclei, how they may be applied to various taxa and their significance in evolution and phylogeny.He interestingly concludes with the belief that primitive Basidiomycetes were binucleate, clamped, and heterothallic. Nuclear behavior is approached in greater depths by John R. Raper and A. S. Flexer in their presentation of "Mating iystems and Evolution of Basidiomycetes". They nota that such features as various forms of basidia, the dolipore septum, the dikaryon, the clamp connection, and several mating systems which occur in these taxa, if correctly read, should indicate the course of evolution with some degree of accuracy. Their text deals mainly with mating systems, expecially the control of sexual morphogenesis in Schizophyllum commune. Dr. Mildred Nobles, (Plant Research Institute, Ottawa, Canada), convincingly attempts to show that a knowledge of extracellular enzymes, such as oxidise, correlated with other cultural and morphological features, can aid greatly in showing relationships among wood inhabiting basidiomycetes. Her paper, entitled "Cultural Characters as a Guide to the Taxonomy of the Polyporaceae" provides a unique, but useful, key to numerous species of these fungi. A somewhat similar approach to the Agaricaceae is made in Orson K. Miller's (U. S. Forest Service, Beltsville, Md.) paper on "The Relationship of Cultural Characters of the Agarics". He refers mainly to his studies of several genera of Tricholomataceae, emphasizing the types of asexual spores, cell types, microchemical reactions in vegetative cells, and other features that might provide phylogenetic information. A rather novel approach to a study of evolution was suggested in Edward Hacskaylo's (USDA, Forest Physiology Lab., Beltsville, Md.) paper on "The Role of Mycorrhizal Association in the Evolution of Higher Basidiomycetes" in which he suggests that mycorrhizal associations may have evolved much earlier within primitive higher plants, and in effect may indicate that these fungi are mor primitive than those that have developed a similar association with more advanced plant groups.

Part III consists of a series of papers on "Systematic Studies of Fungus Groups". The first of these is Donald P. Rogers' (Univ. of Illinois, Urbana) "Patterns of Evolution of the Homobasidium". He stressed that some characters are of greater, even enormously greater, importance that others; this being the basidium of the basidiomycetes. The question of whether the heterobasidium or the holobasidium is primitive, and the possible evolutionary pathways between the two are discussed. Variation in the resupinate homobasidiomycetes is dealt with by M. P. Christiansen (Copenhagen, Denmark) in his paper by that title. He describes and illustrates the types of spores, basidia, and sterile elements found within the resupinates. Robert L.

Gilbertson (Univ. of Arizona, Tuscon) presents a somewhat similar account in another group in his "Phylogenetic Relationships of Hymenomycetes with Resupinate, Hydnaceous Basidiocarps". Along with a discussion of cultural, developmental, and morphological characteristics, a key to genera of Aphyllophorales containing species with resupinate, hydnaceous basidiocarps is provided. The "Diversity and Phylogenetic Position of the Thelephoraceae" is presented by Albert Pilat (Narodni Museum, Prague, Czech.). we find the beginnings of the evolutionary branches of almost all eubasidiomycetes as well as the meeting point of various branches of the Auriculariales and Tremellales. He discusses the evolution of basidiomycetes in general, the influence of hyphal systems, and characters used in grouping species. Evolutionary lines away from the Thelephoraceae are suggested in Derek Reid's (Kew, England) "Intermediate Generic Complexes Between the Thelephoraceae and other Families". Problems of classification at the family level are stressed in light of the sharp contrast of this family in the traditional versus modern restricted circumcription. Ronald Petersen (Univ. of Tennessee, Knoxville) in his "Interfamilial Relation-ships in the Clavarioid and Cantharelloid Fungi" pictures them as intermediate groups in which the direction of evolution is difficult to establish. Yet, evolutionary path-ways are suggested for several groups. In "The Evolutionary Lines in the Fungi With Spines Supporting the Hymenium", Kenneth Harrison (Univ. of Michigan, Ann Arbor) concludes that spined taxa are present in a number of genera that are not even closely related and that spines can best be regarded as primitive. Several directions of evolution seem to be exemplified in various genera of hydnums. "Multiple Convergence in the Polyporaceous Fungi" was the subject of a second paper by M. A. Donk (Rijksherbarium). Along with a general discussion of family delimitation and the "peculiarities" of liberal and conservative taxonomists, he evaluates all of the features of the growth and development of polypores as to their use in taxonomy. Harry Theirs (San Francisco State College) discusses "Some Ideas Concerning the Phylogeny and Evolution of the Boletes". In this group one is confronted with the major difficulty of deter-mining characters which might be potentially significant in indicating phylogenetic relationships. Of those, hymenial configuration and perhaps spores provide the

43

most useful information. The possible affinities of other agarics and gasteromycetes to the boletes are also discussed. "A Revision of the Genus Melanomphalia as a Basis of the Phylogeny of the Crepidotaceae" is the subject of a paper by Rolf Singer (Field Museum of Natural History, Chicago). He also provides keys and descriptions for 17 species of the genus, along with a discussion of family relationships. Some overall aspects of evolution of fungi are discussed by Alexander Smith (Univ. of Michigan) in his "Origin and Evolution of the Agaricales". He feels that perhaps the basidiomycetes is one of the latest groups of plants to undergo an extremely rapid evolution. To climax a series of excellent papers, one would be pressed to find a more capable individual than Roger Heim (Museum of Natural History, Paris). Broad phylogenetic pathways for the series Asterosporae, the Boletaceae, the Agaricales, and a general phylogenetic scheme for all of the basidiomycetes are presented in his paper on the "Interrelationships Between the Agaricales and Gasteromycetes".

Lively discussions follow almost all of the above papers. Very often there is not a consensus, and frequently much useful information is received through these discussions.

I have little or no adverse criticism of the book. After reading a number of the papers, one is impressed with a repetition of the same ideas, theories, or references. However, this often signifies the enormous contributions that certain individuals have made to the field. It is unfortunate that some of these individuals were not able to participate in the symposium. Notable was the absence of E. J. H. Corner whose developmental studies have been widely followed by both ascomycete and basidiomycete specialist.

The prominence of the authors, the nature of their subjects, and the vast amount of bibliographic informations on fungal evolution will make this book one of the most widely sought after. It certain to become a standard reference for most mycologists. The authors, the editor, and the publisher should be congratulated for a very useful and attractive hook.

James W. Kimbrough

KEN-ICHI, KOJIMA. (Editor) Vol. 1 Biomathernatics. Mathematical Topics in Population Genetics. Springer Verlag, New York, Inc. 1971. 400 pp., 55 figs. $17.70.

The field of biomathematics has always been rather fragmented and there are very few textbooks in the area which attempt, let alone succeed in giving an overview of the applications and uses of mathematics in biology. In the past the student of the discipline has had to rely on chapters in various biology or mathematics textbooks giving specialized knowledge about one particular aspect of the field, and on review articles in the literature. The appearance of a series of monographs of biomathematics has the possibility of filling a void in the scientific literature and is therefore particularly welcome.

The first volume is devoted to mathematical topics in population genetics (the second volume to be devoted to stochastic processes and applications in biology and medicine), and each of the authors in this book are well-known for their development of a particular aspect of genetics. The title and the price may scare away the casual biologist-reader, which is perhaps unfortunate since several of the articles in this volume are not unduly mathematical in nature and are of considerable significance to the understanding of principles of population biology.

There are several articles of value in this volume; the first article by Professor Sewall Wright is a clear ex-position of his "shifting balance" theory of evolution, long regarded as a cornerstone of population genetics. His paper includes recent development of the theory and a particularly valuable section is devoted to answering criticisms and misinterpretations by other authors. A crucial feature of Wright's theory is the random differentiation of gene frequencies in small populations. Wright was the first to work out the expected distribution of gene frequencies in small populations, and his work was extensively developed by Kimura. The article in this volume by Kimura analyses the effects of small population size under certain conditions of mutation, selection, etc. Diffusion equations, which employ continuous approximations to gene- frequency change are used exclusively to derive the results in this paper.

J. R. G. Truner takes considerable pains to produce a comprehensive review of work relating to Fisher's fundamental theorem of natural selection. Many workers have pointed out that Fisher's theorem is not as general as it was first thought, and Turner's review is an excellent summary of all the work on the subject. The paper will be invaluable for a research worker investigating extensions or limitations of the theorem, but probably not for many others. Fisher's fundamental theorem has in the past attracted considerable interest probably only due to Fisher's rather optimistic use of the adjective "fundamental".

Detailed analysis of two locus polymorphisms was initiated by Lewontin and Kojima in 1960. In this volume these authors review the dynamics of two locus systems and present some recent analytic results due to Karlin and Bodmer. The nature of and importance of interallelic interactions is discussed both in terms of experimental situations and in terms of multi-locus models.

Levins' article deals with an old and important concept in population genetics, the relationship between fitness and optimization. This paper and others by Levins at-tempt to insert ecological concepts into population genetics models. The results he obtains are very important to an understanding of the population genetics of natural populations. However, this article tends to be rather terse and highly mathematical in nature and one fears it well be overlooked by many biologists who should be acquainted with the ideas in this paper.

Population genetics has always been closely allied to the applied fields of plant and animal breeding and three papers in this volume reflect this close relationship. All three deal with a central problem in selection experiments, namely which strategy should be employed to maximise the genetical potential of a population. W. G. Hill compares specific selection regimes with a relatively simple model (genetically speaking) whereas Robertson's article takes a more general approach to the problem with a multilocus model. Selection schemes inevitably involve a considerable amount of inbreeding which can lead to the fixation of loci for alleles which are not necessarily advantageous. The paper by Cockerham takes a probabilistic approach to ask the question, which type of mating pattern allows the minimum amount of fixation.

The articles of Schaffer and Li have a somewhat different orientation to the rest of the papers in this collection. They each consider a specific aspect of probability theory and illustrate how it may be used to answer questions in population genetics. Schaffer's paper deals with branching processes, and demonstrates how the theory can be applied to determining the ultimate survival probability of mutant genes. The paper of Li's is

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probably more interesting insofar that it points out a common statistical complication which is usually ignored or overlooked in many studies. In many cases experimental data conforms to a binomial distribution, but often the frequency of one or more classes is impossible to ascertain. The analysis of this type of situation is illustrated in terms of examples from human genetics (segregation analysis). This paper should be very illuminating for the biologist concerned with the correct analysis of his data.

Julian Adams

DICKSON, DIANE AND CAROL DOSSOR. World Catalog of Theses on the Pacific Islands. Pacific Monograph Series No. 1, University of Hawaii Press, Honolulu, Hawaii. 1970. 135 pp. $4.25.

This ambitious undertaking is presented as an expansion of an Index of Social Science Theses on the South Pacific published in 1957. From the title, one would expect that it would be a rich source for tracing botanical and biological studies as cited;, the selection is heavily oriented to the social sciences. The basis for selection of botanical titles is obscure — A. R. H. Lamberton's study of The anatomy of some woods utilized by the ancient Hawaiians (1955) is included but numerous floristic, taxonomic, anatomical, physiological, and microbiological theses from the same period were overlooked, even though of broader botanical interest than Lamberton's study. Further, although both the compilers and general editor are apparently aware of the publication of Dissertation Abstracts, it is clear that a thorough check of titles from every U. S. institution was not made. Thus, Glassman's Ph.D. dissertation on the flora of Ponape (published in 1952) submitted to a university not specializing in Pacific island studies was overlooked just as many similarly produced American dissertations have been. Let us hope that the next edition provides better coverage for botanical science. Until then, a library copy should suffice for any botanist except the most dedicated Pacificophile.

Harvey A. Miller

WILLAMAN, J. J., AND HUI-LIN LI. Alkaloid-bearing Plants and Their Contained Alkaloids, 1957-1968. Lloydia, Supplement Vol. 33, no. 3A, Cincinnati, Sept. 1970. 286 pp. paperbound. $5.00.

This work consists of two lists, the names of plants arranged in taxonomic groups, giving their contained alkaloids, with literature references; and secondly, a list of the names of alkaloids and their empirical formulas with references to where they are to be found in the first list. It represents a continuation of a previous compilation through 1957 that was issued as a U. S. D. A. Technical Bulletin no. 1234.

The amount of data published on alkaloids in plants (luring the 1957-1968 period is quite enormous, and ac-cording to the authors, exceeds that of all records ac-cumulated in the past up to 1957. This volume brings together in convenient listings, a great. amount of data on the occurrence of alkaloids in plants from many scattered literature sources. It does not attempt to describe or interpret or to give structural formulas, but it is rather a basic guide to the voluminous literature. It is a valuable and useful reference work.

Sydney S. Greenfield

PLANT SCIENCE BULLETIN LIFE SCIENCE BUILDING UNIVERSITY OF SOUTH FLORIDA TAMPA, FLORIDA 33620