2006 Conant "Botanical Images" Student Travel Award

The Botanical Society of America, in conjunction with Paul Conant, has reinvented the “Conant Student Travel Award”. As the BSA's presence on the web has developed, we have watched more and more young people coming online to look at and explore the fascinating range of plant images BSA members have shared with each other for years. From the vibrant microscopy images through to those depicting entire ecosystems, pictures are always an enticing way to learn and teach about all things botanical.

Using this concept as an opportunity to support student development and to bring forward more images from the wonderful world of the plant sciences seemed a logical marriage. We trust you will enjoy the results!

Submission #1
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Title: A hover fly collects pollen from a Phacelia (Hydrophyllaceae) flower
Author: Anna Jacobsen
Institution: Michigan State University
Department: Plant Biology
Topic/Discipline: Pollination Ecology
Family: Hydrophyllaceae
Species: Phacelia sp.
Caption: A hover fly uses its vacuum-like mouth to remove pollen from an anther of a Phacelia (Hydrophyllaceae) flower in the Antelope Valley California Poppy Preserve, USA.
Scientific Description/Explanation: The arid habitat of the Antelope Valley California Poppy Preserve, USA, appears dry and lifeless for much of the year, but following the rainy season it bursts with the brilliant colors of the spring wildflower bloom. Many insects can be seen flying about pollinating flowers as they collect nectar and pollen. In this photo, a hover fly can be seen collecting pollen from a Phacelia (Hydrophyllaceae) flower. The fly has a short thick vacuum-like mouth, which it uses to suck up pollen from the flower anther. Although hover flies eat much of the pollen they collect, they also provide a valuable service to flowers by transferring pollen from one flower to another.
Date taken: April 2, 2005
Season/time of year: Spring
Area: Antelope Valley California Poppy Preserve, State Reserve California State Parks
State/Province: California
Country: USA
Key words: Phacelia, Hover fly, pollination, flower, California

Submission #2
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Title: Garrya fremontii Torrey
Author: Dylan O. Burge
Institution: Duke University
Department: Biology
Topic/Discipline: Vascular plant systematics
Family: Garryaceae
Species: Garrya fremontii
Common name: Fremont's silk tassel
Caption: Female inflorescence of Garrya fremontii Torrey, Fremont's silk tassel.
Scientific Description/Explanation: The genus Garrya Dougl. ex Lindl. [See "Terms From Scientific Description," below, for explanations of terms in italics] (Garryaceae) contains 15 species of winter-blooming, wind-pollinated, dioecious evergreen trees and shrubs distributed in North America (including Mexico), Central America, and the Caribbean Islands. The genus Garrya is found only in the New World, but is closely related to the genus Aucuba, which is native to China and Japan. The genus Garrya is thought to represent a relatively recent introduction to the New World, which probably migrated from Asia over a high-latitude land-bridge sometime during the last twenty million years. Garrya fremontii is a widespread species that occurs from central California to Washington State. It is most abundant at middle and high elevations (1000-3000 meters) in parts of the Sierra Nevada Mountains, the Pacific Coast Ranges, and the Cascade Range. It occupies a diversity of habitats, from chaparral and oak woodland to coniferous forests. The plant in the photograph is part of a population of Garrya fremontii growing on Doe Mill Ridge in Butte County, California, about 15 kilometers north-northeast of the town of Chico. These plants are part of a dense chaparral community composed mainly of species of Arctostaphylos (manzanita) and Ceanothus. This community is strongly fire regulated, with fires occurring about every seven to ten years. Garrya fremontii, along with many other members of this chaparral community, survives fire by re-sprouting from a buried root-crown, or lignotuber. It also regenerates from seeds deposited in the soil seed-bank. Garrya fremontii is part of a complex of species from western North America, within which the species are very difficult to differentiate. Garrya fremontii intergrades morphologically with Garrya flavescens in the coast ranges of California, which may indicate that these two taxa are not distinct. In addition, preliminary results using DNA sequence data (see URL below) suggest that there is very little genetic variation among species of Garrya in California. Like all species in the genus, Garrya fremontii flowers during the late winter, long before most plants have begun their growing season. The flowers are born in pendulous inflorescences, as shown in the image, and have a unique, highly reduced structure. In female inflorescences the flowers are arranged in successive groups that are each partially surrounded by a bract. In the photograph, these bracts are obvious as the greenish, triangular flaps that cover the bases of the silky, developing ovaries. Opposite bracts sometimes fuse, forming a cup that surrounds multiple groups of flowers. Individual female flowers lack almost all vestiges of a corolla or calyx, although minute remnants of these structures are sometimes present near the base of the styles. The presence of these perianth remnants is usually taken as evidence that the ovaries of Garrya fremontii are inferior. The ovaries of all Garrya species are composed of two carpels, and thus produce two seeds. The styles of Garrya fremontii are characteristically elongated and thin, often recurving toward the inflorescence axis, which gives the appearance of a "handle-bar mustache." This character is clearly visible in the image, although some of the styles have dried up and broken off, as the inflorescence in the image is several weeks old and past the fertilization stage. Male inflorescences are not shown in the image, but male plants were present in the vicinity of the pictured plant. Male inflorescences are also morphologically reduced, and specialized for wind pollination. These adaptations include a special chamber formed from the distally fused perianth members that is thought to aid in preventing desiccation of the pollen. The male inflorescence is also less rigid than the female inflorescence, which enables it to flex with the wind currents. Most species of Garrya flower well before the time when potential pollinators are active, sometimes while snow is still on the ground, so scientists have inferred that they are wind pollinated. The fruits of Garrya fremontii mature in the fall, and are dark blue in color. It is not certain what the primary dispersal agent of this plant may be, but species of Neotoma (wood rats) are known to collect them. Overall, Garrya fremontii, and the genus Garrya in general, present an intriguing combination of highly derived morphological traits, unusual ecology, and potentially complex genealogical and geographical patterns going back to the Old World. Garrya also takes readily to cultivation, and several species and hybrids are popular landscape plants in the Western United States. TERMS FROM THE EXPLANATION Garrya - The scientific name of any organism should always be underlined or printed in italics. The scientific name of an organism always has two parts, the genus name (Garrya, for instance), and the species name (fremontii, for instance). Because of the parts of speech corresponding to these two words, and convention, the first is always capitalized, while the latter is never capitalized. Dougl. ex Lindl - In plant taxonomic treatments, papers, floras, labels, etc., the name of a plant taxon is often given along with the name of the authority for that taxon (the author of the taxon name). In the case of the genus Garrya, the authority is Lindley, who was the first to validly publish (sanction) the name Garrya, which had been proposed, but not validly published, by Douglas. Dioecious - Most plants have bisexual flowers, with male and female parts combined within the same structure. However, some taxa have the male and female parts separated into different flowers. If both female and male flowers occur on the same plant, then the species is known as monoecious. If the flowers are born on separate plants, analogous to the two-sex system of many animals, then the plant is known as dioecious. DNA sequence - DNA (Deoxyribonucleic acid) is the information-carrying molecule of living things. DNA, which encodes information for building proteins, is the basis for almost all of the characteristics of a given organism, as expressed during development. Scientists use DNA to gain insight into the history of life on earth, and the dynamics of living systems. This is possible because of the unique hereditary role of DNA, which accumulates errors in living organisms, some of which are passed on to subsequent generations. DNA can be extracted from living organisms and its code, or sequence, can be read using specialized techniques. This information may be used in a statistical fashion to infer the genealogy of a group of organisms, such as a genus or species of plant. Inflorescence - The reproductive part of a plant, including all flowers and the stems on which they are born, is called an inflorescence. There is considerable diversity in inflorescence structure among flowering plants. A daisy "flower," for instance, is really an inflorescence containing several hundred individual flowers. Bract, carpel, ovary, corolla, calyx, perianth, style - Most flowers are composed of four "whorls" of parts. (1) The female parts, or carpels, which each have an ovary as well as a stigma (the receptive surface for pollen) that is born on the end of a style. (2) The male parts, or stamens, which are made up of pollen-bearing anthers on the end of filaments. (3) The petals, which together are known as the corolla. (4) The sepals, which are typically green and collectively called the calyx. The calyx and corolla are together known as the perianth. All of these flower parts are attached to a receptacle, which is often born on the end of a stalk called the pedicel. This pedicel is often subtended by (found immediately above) a leaf-like organ called a bract. All of the amazing and beautiful diversity of flower morphology is simply variation on this theme of four whorls and subtending elements. Inferior - When the corolla and calyx become fused to the walls of the carpels so that the stamens, anthers, and stigmas appear anatomically above the ovary, rather than below it, then the ovaries of that flower are termed inferior. Normal ovaries are termed superior. An apple, for example, is derived from a fertilized flower with inferior ovaries. The perianth, stamens, and styles are often visible in the depression on the distal end of the apple (opposite the stem, or pedicel). Distally - In anatomical terms, an organ that is far from a point of reference is distal, while an organ that is near is proximal. Your hand, for instance, is on the distal end of your arm. These terms are used universally in discussions of both animal and plant anatomy. Derived - Genealogies of organisms are also known as phylogenies. Humans, apes, and monkeys, for instance, are all related, and the specific genealogical relationships between them, as inferred from morphological traits or DNA sequence variation, can be expressed as a branching, tree-like phylogeny, in which the earliest-branching lineages (those appearing lowest on the tree) are considered as ancestral, and the most recent, latest branching lineages are considered as derived. REFERENCE MATERIAL Bremer, B., Bremer, K., Heidari, N., Erixon, P., Olmstead, R.G., Anderberg, A.A., Källersjö, M., & Barkhordarian, E. 2002. Phylogenetics of asterids based on 3 coding and 3 non-coding chloroplast DNA markers and the utility of non-coding DNA at higher taxonomic levels. Molecular Phylogenetics and Evolution 24: 274-301. Dahling, G.V. 1978. Systematics and evolution of Garrya. Contributions from the Gray Herbarium of Harvard University 209: 1-104. Eyde, R.H. 1964. Inferior ovary and generic affinities of Garrya. American Journal of Botany 51: 1083-1092. Graham, A. 1999. The tertiary history of the northern temperate element in the northern Latin American biota. American Journal of Botany 86: 32-38. Hileman, L.C., Vasey, M.C., & Parker, V.T. 2001. Phylogeny and biogeography of the Arbutoideae (Ericaceae): implications for the Madrean-Tethyan hypothesis. Systematic Botany 26: 131-143. Liston, A. 2003. A new interpretation of floral morphology in Garrya (Garryaceae). Taxon 52: 271 276. Oxelman, B., Yoshikawa, N., McConaughy, B.L., Luo, J., Denton, A.L., & Hall, B.D. 2004. RPB2 gene phylogeny in flowering plants, with particular emphasis on asterids. Molecular Phylogenetics and Evolution 32: 462-479.
Area: Doe Mill Ridge, Butte County
State/Province: California
Country: USA

Submission #3
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Title: In the indusium of Cyathea cranhamii
Author: Selena Smith
Institution: University of Alberta
Department: Biological Sciences
Topic/Discipline: Paleobotany
Family: Cyatheaceae
Species: Cyathea cranhamii Smith, Rothwell et Stockey 2003
Caption: The globose indusia of the fossil tree fern, Cyathea cranhamii, enclose numerous stalked sporangia with trilete spores.
Scientific Description/Explanation: Tree ferns occur throughout the world in predominantly tropical habitats. The group has a long history and is known since the Jurassic, ca. 160 million years ago. Fossils of this family, Cyatheaceae, are usually carbon imprints (called compression fossils) of leaves. Other fossils, such as the stems of tree ferns, are petrified, with the organic plant material mostly replaced by minerals. This image of the indusium of Cyathea cranhamii Smith, Rothwell et Stockey shows sporangia with spores. Spores are triangular with a trilete mark. The sporangia have areas with thickened cell walls (the annulus), which help in dehiscence (the opening of the sporangium) and spore dispersal. Sporangial stalks are visible as small clusters of four to six cells in cross section. Cyathea cranhamii comes from late Cretaceous (ca. 130 million years ago) sediments of British Columbia, Canada and represents the first known permineralized reproductive tree fern material.
Date taken: July 1, 2002
Additional Image Credits: Gar Rothwell, Ohio University, Environmental and Plant Biology, Athens, Ohio, USA Ruth Stockey, University of Alberta, Biological Sciences, Edmonton, Alberta, Canada
Key words: British Columbia, Cretaceous, Cyathea cranhamii, Cyatheaceae, Filicales

Submission #4
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Title: Ledothamnus sessiliflorus
Author: Erin Tripp
Institution: Duke University
Department: Biological Sciences
Topic/Discipline: Plant Taxonomy, Botanical Exploration
Family: Ericaceae
Species: Ledothamnus sessiliflorus (Ericaceae)
Caption: Ledothamnus sessiliflorus (Ericaceae): an endemic genus of the Guiana Highlands
Scientific Description/Explanation: This is a photograph of Ledothamnus sessiliflorus N.E. Brown (Ericaceae: blueberry family). The genus of seven species (Luteyn 1995) is found only in the Guiana Highlands of northern South America, a region known for its pristine habitat and highly endemic flora. Ledothamnus was thought to be endemic to tepui summits of the Venezuelan Guyana. During the summer of 2004, it was collected in Guyana by Dr. David Clarke (Univ. of North Carolina-Asheville), Stephen Stern (Univ. of Utah), Diana Gittens (Univ. of Guyana), Amerindian collaborators, and myself from the summit of Mt. Maringma. Maringma, slightly east of Mt. Roraima, is the highest tepui wholly within Guyana (2200 m / 7200 ft.) and was previously unexplored biologically. Its tepui summit hosts genuine cloud forests characterized by quaking bogs, rocky outcrops, and dense, tangled vegetation. At 5° N latitude, environmental parameters are extreme and include harsh winds and bouts of intense rainfall then intense sunshine. The photo of Ledothamnus sessiliflorus shows its 8-parted flower with a superior, verrucose ovary. Its morphology and growth form are bizarre in appearance, like so many other tepui plants. On Maringma it occurs as a stunted, ankle-high "terrestrial" shrublet. Luteyn used adjectives such as "wiry" and "gnarled" to help describe it in his taxonomic treatment (1995). Such discoveries of endemic and other plants of the Guyanese tepuis point to the need for further botanical research in the area and better conservation strategies of this truly unique and eccentric ecosystem. The L. sessiliflorus specimen has been deposited in the United States National Herbarium, as part of the Smithsonian's Biodiversity of the Guianas Program. Luteyn, J.L. (ed.). 1995. Ericaceae--Part II. The Superior- Ovaried Genera. Flora Neotropica Monographs. Vol. 66.
Date taken: 15 June, 2004
Area: Mt. Maringma, tepui, western Guyana
Country: Guyana
Additional Image Credits: Dr. David Clarke, University of North Carolina-Asheville

Submission #5
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Title: Root holoparasite Hydnora africana in full bloom.
Author: Jay F. Bolin
Institution: Old Dominion University
Department: Biological Sciences
Topic/Discipline: Plant Parasites
Family: Plant Parasite: Hydnoraceae; Host Plant: Euphorbiaceae
Species: Plant Parasite: Hydnora africana; Host Plant: Euphorbia mauritanica
Caption: Flower of Hydnora africana (foreground) parasitizing its host Euphorbia mauritanica (background).
Scientific Description/Explanation: The bizarre floral appearance of Hydnora africana seems almost extraterrestrial, but in fact it is finely adapted for pollination in its arid habitat. This plant, resident of southern Africa only emerges from the soil to flower. After the fleshy petals open, the flower begins to emit an odor of rotting meat to attract its pollinators, carrion flies and beetles. The unusual underground habit and lack of leaves may be explained by its mode of nutrition. Hydnora africana is a root holoparasite. Thus it has no need for sunlight to generate sugars, it has no chlorophyll and attains all nutrients and water from the roots of its shrubby host plant (in the background) Euphorbia mauritanica.
Date taken: December 10, 2005
Season/time of year: Spring
Area: Richtersveld: Farm Gemsbokvlei
State/Province: Northern Cape Province
Country: South Africa
Additional Image Credits: Dr. David Clarke, University of North Carolina-Asheville

Submission #6
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Title: Woody Flowering Plant Twig from the Eocene of Oregon
Author: Richard W. Tate
Institution: Humboldt State University
Department: Biological Sciences
Topic/Discipline: Paleobotany
Family: Dicotyledones
Species: unidentified
Caption: Cross section of a twig from a woody flowering plant that lived during the Eocene epoch, approximately 40 million years ago. The specimen is anatomically preserved by silica mineralization in rocks known as the Clarno Chert. All tissues are preserved, from the central pith to the outer bark. The plant was part of a subtropical community inhabiting marshlands in what is now central Oregon.
Scientific Description/Explanation: Cross section of a twig from a woody flowering plant that lived during the Eocene epoch, approximately 40 million years ago. The specimen is anatomically preserved by silica mineralization in rocks known as the Clarno Chert. All tissues are preserved, from the central pith to the outer bark. The plant was part of a subtropical community inhabiting marshlands in what is now central Oregon.
Date taken: April 2006
Area: Central Oregon
State/Province: Oregon
Country: USA

Submission #7
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Title: Pellia epiphylla sperm cell
Author: Andrew Blackwell
Institution: Southern Illinois University, Carbondale
Department: Plant Biology
Topic/Discipline: Ultrastructure
Family: Metzgeriidae
Species: Pellia epiphylla
Caption: Three-dimensional picture of Pellia epiphylla sperm cell
Scientific Description/Explanation: This is a three-dimensional image of a sperm cell of the liverwort, Pellia epiphylla, drawn from two-dimensional TEM images. Sperm cells are released from the male antheridia located on the thallus and swim to a receptive female egg. Upon fertilization, a zygote is formed.
Additional Image Credits: Cassandra Rogers, Karen Renzaglia, Southern Illinois University, Carbondale
Key words: Liverwort, Sperm cell

Submission #8
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Title: Circinate Vernation
Author: Ryan McMillen
Institution: Southern Illinois University
Department: Plant Biology
Topic/Discipline: Plant Morphology
Family: Moniliphyte
Species: Thelypteris extensa
Caption: Circinate vernation in Thelypteris extensa
Scientific Description/Explanation: In most ferns the young leaf uncoils during development; these coiled fronds are commonly referred to as "fiddle heads". This photo shows this type of leaf development, known as circinate vernation in Thelypteris extena.
Date taken: March 15, 2006
Season/time of year: Winter
State/Province: Illinois
Country: USA
Key words: Fern, frond, circinate vernation, fiddle head, thelypteris extensa

Submission #9
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Title: Circinate Vernation
Author: Ryan McMillen
Institution: Southern Illinois University
Department: Plant Biology
Topic/Discipline: Plant morphology
Family: Moniliphyte
Species: Thelypteris extensa
Caption: Circinate vernation in Thelypteris extensa
Scientific Description/Explanation: In most ferns the young leaf uncoils during development; these coiled fronds are commonly referred to as "fiddle heads". This photo shows this type of leaf development, known as circinate vernation in Thelypteris extena.
Date taken: March 15, 2006
Season/time of year: Winter
State/Province: Illinois
Country: USA
Key words: Fern, frond, circinate vernation, fiddle head, thelypteris extensa

Submission #10
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Title: Circinate Vernation
Author: Ryan McMillen
Institution: Southern Illinois University
Department: Plant Biology
Topic/Discipline: Plant morphology
Family: Moniliphyte
Species: Thelypteris extensa
Caption: Circinate vernation in Thelypteris extensa
Scientific Description/Explanation: In most ferns the young leaf uncoils during development; these coiled fronds are commonly referred to as "fiddle heads". This photo shows this type of leaf development, known as circinate vernation in Thelypteris extena.
Date taken: March 15, 2006
Season/time of year: Winter
State/Province: Illinois
Country: USA
Key words: Fern, frond, circinate vernation, fiddle head, thelypteris extensa

Submission #11
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Title: Long lived and sharp leaves that would puzzle (or injure) a monkey.
Author: Chad Husby
Institution: Florida International University
Department: Biological Sciences
Topic/Discipline: Plant Morphology
Family: Araucariaceae
Species: Araucaria araucana
Caption: Trunk, leaves and branches of a young Araucaria araucana, Reserva Nacional Malalcahuello, Araucanía Region, Chile.
Scientific Description/Explanation: This photograph shows the remarkably persistent leaves on the trunk of a young pehuén (also called the monkey puzzle tree), Araucaria araucana, in the central Chilean Andes. Even as the main trunk of this slow-growing conifer expands and becomes woody, the trunk leaves remain green and apparently functional. The very stiff and prickly leaves of this species are among the most long-lived of all plants, with a mean leaf lifespan estimated at 24 years (Lusk, 2001). Interestingly, the toughness of Araucaria araucana's leaves accounts for its English common name. Around 1850, an observer of a young tree being grown in Cornwall, England remarked, in reference to the tree's sharp and prickly leaves, "It would puzzle a monkey to climb that". Lusk, C. H. 2001. Leaf lifespans of some conifers of the temperate forests of South America. Revista Chilena de Historia Natural 74:711-718.
Date taken: January 19, 2006
Season/time of year: Summer
Area: Reserva Nacional Malalcahuella, near Volcán Lonquimay. Volcán Lonquimay is an active stratovolcano that last erupted in 1990.
State/Province: Araucanía Region
Country: Chile
Key words: Araucariaceae, Araucaria araucana

Submission #12
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Title: "Biting off more than you can chew"
Author: Theresa (Meis) Chormanski
Institution: Florida International University
Department: Biological Sciences
Topic/Discipline: Carnivorous Plants/Aquatic Botany
Family: Lentibulariaceae
Species: Utricularia gibba
Caption: A Utricularia gibba trap has caught an unsuspecting victim; a bisected insect larva.
Scientific Description/Explanation: Utricularia gibba is an aquatic, carnivorous plant. Utricularia species, commonly called the Bladderworts, are found in aquatic areas throughout the United States living in bodies of water or moist environments, such as bogs. This specimen was collected in a pond in South Florida, but visitors to Everglades National Park would be able to see several Utricularia species. The traps of this plant are very small, only a few millimeters, and are easily missed unless the observer looks closely. Hundreds of traps are found along the plant body, a horizontally growing stem called a stolon. Bladderworts are the only carnivorous plant that catches prey by a suction trap. These traps actively expel water from the inside of the trap, or the trap lumen. While the traps excrete water, the trap sides are sucked in and the trap walls appear concave. Once the trap is set, it is ready to catch prey. Small organisms, such as rotifers, copepods and mosquito larvae, swimming in the water or grazing on Utricularia, may accidentally hit the trigger hairs, appendages at the front of the trap, and cause the trap door to open inward. Once the trap door is open, water and the unsuspecting organism rush in with the trap door closing behind the prey. After the trap has fired, the trap walls are convex and appear more round. Although complex, the trapping process, including resetting, takes only thousands of a second. Digestion of the prey follows capture via four and two-armed hairs inside the trap lumen. Carnivorous plants, including Utricularia species, are usually found in nutrient poor sites and their ability to trap and digest prey allows them to supplement available nutrients and survive in nutrient poor habitats.
Date taken: This photo was taken in July 2005 during the wet season. This picture was taken with the use of a dissecting scope and is at 25x magnification.
Area: Pond located at Florida International University, Miami
State/Province: Florida
Country: USA
Key words: Utricularia gibba, carnivorous plants, aquatic botany

Submission #13
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Title: x.s. of a Cycadeoidea stem
Author: Patricia Elizabeth Ryberg
Institution: University of Kansas
Department: Ecology and Evolutionary Biology
Topic/Discipline: Paleobotany, Plant Anatomy
Family: Bennettitales
Caption: Secondary xylem (bottom), cambial zone, and secondary phloem (top)
Scientific Description/Explanation: Cycadeoidea (Bennettitales) is an extinct genus of seed plants that thrived in the Cretaceous (100 million years ago). This specimen was collected from the Black Hills of South Dakota. At the bottom of the picture is secondary xylem (wood) represented by the dark colored cells. At the top of the image is secondary phloem. Phloem is rarely preserved in the fossil record and the excellent preservation seen here is vital to studies on vascular tissue in fossil plants. (specimen from Yale University Peabody Museum of Natural History)
Area: Collected from the Black Hills of South Dakota
State/Province: South Dakota
Country: USA

Submission #14
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Title: Equisetum Stomata
Author: Ryan McMillen
Institution: Southern Illinois University
Department: Plant Biology
Topic/Discipline: Plant anatomy
Family: Moniliphyte
Species: Equisetum arvense
Caption: Equisetum arvense stem with stomata and silica protrusions.
Scientific Description/Explanation: Stomata regulate gas exchange and are interspersed among flat tightly packed epidermal cells. This colorized scanning electron micrograph shows the sunken stoma of Equisetum arvense with the guard cells nearly hidden by overlying subsidiary cells. Highlighted in grey is the silica found in the epidermis, which gives Equisetum arvense a rough feel and the common name scouring rush.
Date taken: February 6, 2006
Season/time of year: Winter
Key words: Stomata, stoma, silica, guard cells, subsidiary cells, equisetum

Submission #15
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Title: Dioon
Author: Ryan McMillen
Institution: Southern Illinois University
Department: Plant Biology
Topic/Discipline: Plant morphology
Family: Gymnosperm, Cycad
Species: Dioon spinulosum
Caption: Cluster of leaves at the top of a Dioon stem.
Scientific Description/Explanation: Dioon spinulosum is a gymnosperm that links ancient plants to today. With an explosion in the Mesozoic era, in concert with dinosaur diversification, this era is often referred to as the "Age of Cycads and Dinosaurs". The leaves of cycads occur in a cluster at the top of the stem and resemble palms. Unlike palms, cycads exhibit true secondary growth from a vascular cambium.
Date taken: February 25, 2006
Season/time of year: Winter
Area: Green house- Southern Illinois University
State/Province: Illinois
Country: USA
Key words: Dioon, Leaves, Cycad

Submission #16

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Title: S

Submission #17
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Title: The open sporophyte of Dendroceros crispatus
Author: Joel Long
Institution: Southern Illinois University
Department: Plant Biology
Topic/Discipline: Ultrastructure and development
Family: Dendroceraceae
Species: Dendroceros crispatus
Caption: Scanning electron micrograph of the open sporophyte of the hornwort, Dendroceros crispatus. Image was colorized using Adobe Photoshop CS.
Scientific Description/Explanation: This picture is of a hornwort sporophyte, one of the earliest lineages of land plants. The hornworts are interesting because of many unique features. The sporophyte is the result of fertilization. Hornworts have cone or horn shaped sporophytes. The sporophyte produces haploid spores that grow into new plants. In most hornworts, the spores are a single cell. However, in Dendroceros the spores are multicellular. Most hornworts grow on exposed soil in wet areas. Dendroceros is extremely interesting because it is the only hornwort that grow on trees.
Area: Mt. Lewis W of Rumula, SW slope of summit
State/Province: Queensland
Country: Australia
Additional Image Credits: Dr. Karen Renzaglia, Southern Illinois University, Carbondale, Plant was collected by D. Christine Cargill
Key words: Psilotum, stomata, epicuticular wax

tomata in Psilutum nudum

Author: Ryan McMillen

Institution: Southern Illinois University

Department: Plant Biology

Topic/Discipline: Plant morphology

Family: Moniliphyte

Species: Psilotum nudum

Caption: Sunken stomata of Psilotum nudum

Scientific Description/Explanation: Stomata regulate gas exchange and are interspersed among flat tightly packed epidermal cells. This scanning electron micrograph was colorized to emphasize the sunken stoma of Psilotum nudum, commonly known as the whisk fern. Epicuticular wax is formed as webbing over the gaurd cells.

Date taken: November 9, 2005

Season/time of year: Winter

State/Province: Illinois

Country: USA

Key words: Psilotum, stomata, epicuticular wax