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from article Forensic botany
Surface of a green bean pod, showing its spines using (a) light microscope (courtesy of David O. Norris) and (b) scanning electron microscope (courtesy of Meredith Lane).
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from article Lichens
The ascolichen Teloschistes chrysophthalmus. (Credit: Jason Hollinger)
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from article Lichens
Cuplike lichens of the genus Cladonia. (Credit: Jacinta Lluch Valero)
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from article Ebony
Persimmon (Diospyros virginiana). (Photograph by Dot Paul, National Resources Conservation Service, USDA)
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from article Wheat
A sheaf of wheat (Triticum) surrounded by some small piles of seed (grain). (Credit: Scott Bauer/Agricultural Research Service, U.S. Department of Agriculture)
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from article Wheat
A combined harvester-thresher is used to harvest wheat. (Credit: Scott Bauer/Agricultural Research Service, U.S. Department of Agriculture)
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from article Wheat
Adaptation regions for wheat in the United States. (Credit: U.S. Department of Agriculture)
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from article Wheat
Wheat (Triticum) growing in a field. The wheat inflorescence is a spike bearing sessile spikelets arranged alternately on a zigzag rachis (main axis). (Credit: Tim McCabe/Natural Resources Conservation Service, U.S. Department of Agriculture)
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from article Wheat
Black stem rust of wheat, which produces urediniospores in reddish-brown pustules. The fungus Puccinia graminis f. sp. tritici is responsible for this plant disease. The inset shows a close-up view of an infected stem. (Credit: Agricultural Research…
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from article Wheat
Loose smut of wheat, caused by Ustilago tritici. (Credit: Erik Stromberg/Virginia Polytechnic Institute and State University)
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from article Apical dominance
Model of strigolactone production. Auxin promotes genes (listed below the arrow) required for strigolactone biosynthesis. This can occur in roots and shoots. Strigolactones move into the bud region and are perceived by the F-box response protein,…
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from article Apical dominance
Simplified view of the interaction of three branching hormones. Auxin promotes production of strigolactones (SL), whereas limiting that of cytokinins (CK) at bud nodes. This blocks bud outgrowth in intact plants (left). After decapitation, supply of…
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from article Plant phylogeny
A phylogeny of the major groups of plants, showing the history of diversification from a common ancestor (left). The origin of plants in an endosymbiotic event is not depicted, nor are later secondary endosymbiotic events. Major groups are enclosed…
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from article Plant phylogeny
Primary and secondary endosymbiotic events in the history of plants. Plants originated in a primary endosymbiotic event, when a prokaryotic photosynthetic cyanobacterial cell was engulfed by a eukaryotic cell and maintained as a plastid. This line…
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from article Plant phylogeny
The life cycle of a fern, involving the alternation of sporophyte and gametophyte generations. Reproduction by sporophytes yields gametophytes, and reproduction by gametophytes yields sporophytes. A complete life cycle begins with either a…
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from article Tupelo
Leaves of black tupelo (Nyssa sylvatica). (Photograph courtesy of Larry Allain, USGS National Wetlands Research Center)
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from article Kentucky coffee tree
Seeds of the Kentucky coffee tree (Gymnocladus dioica). (Photo courtesy of Steve Hurst, ARS Systematic Botany and Mycology Laboratory, USDA–NRCS PLANTS Database)
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from article Kentucky coffee tree
Kentucky coffee tree (Gymnocladus dioica). (a) Parts of branch showing leaf scars and winter buds. (b) Branch.
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from article Lepidodendrales
Reconstructions of tree-sized Carboniferous rhizomorphic tree-lycopsids, illustrating architectural variation. (After R. M. Bateman et al., Experimental cladistic analysis of anatomically preserved arborescent lycopsids from the Carboniferous of…
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from article Lepidodendrales
Primitive bisexual cone of the Flemingites type, borne by Paralycopodites, with apically concentrated microsporangia and basally concentrated megasporangia containing several megaspores. (After C. A. Arnold, An Introduction to Paleobotany,…
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from article Sonobuoy
Launch of a sonobuoy from an antisubmarine warfare (ASW) aircraft. (a) In flight. (b) Buoy strikes the water in a nearly vertical attitude. (c) Antenna and hydrophone are positioned automatically.
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from article Fungi
Porcini mushrooms (Boletus edulis) are members of the Basidiomycota division of Fungi. (Credit: Digoarpi/Shutterstock)
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from article Fungi
Spore types (upper illustrations) and structures of parent mycelia (lower illustrations) in fungi.
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from article Fungi
Sporangia of saprophytic Rhizopus. (Credit: Richard Gross; copyright © McGraw-Hill Education)
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from article Fungi
Sexual mechanisms in fungi: (a) gametic copulation; (b) gametangial copulation; (c) gamete-gametangial copulation; and (d) somatic copulation.
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from article Fungi
Colorized scanning electron micrograph of brewer's yeast cells (Saccharomyces cerevisiae). This fungus consists of single vegetative cells, and small daughter cells can be seen budding off from the larger cells. Brewer's yeast is used in the…
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from article Apple
Empire apple (Malus pumila). (Credit: Peggy Greb/Agricultural Research Service, United States Department of Agriculture)
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from article Apple
Apple trees in an orchard in late autumn. (Credit: Sandrine Bouvier/Alamy)
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from article Pericycle
Pericycles. (a) Part of transection of root Actaea alba, including xylem and phloem. Pericycle thin-walled and one cell in radial dimension. (b) Part of transection of root of Smilax herbacea, including phloem. Pericycle thick-walled and four or…
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from article Pericycle
Transection of central part of sugarbeet. (After K. Esau, Hilgardia, 9(8), 1935)
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from article Wood anatomy
Annual tree rings are distinct features of wood anatomy. The combined concentric bands of light and dark areas can help investigators to determine the age of a tree. (Credit: DrimaFilm/Shutterstock)
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from article Wood anatomy
Light micrograph of a section through the stem of a lime tree (genus Tilia). The pith is at the center and is surrounded by a layer of wood (xylem). A thin cambium separates this from the phloem. An outer layer of collenchyma is enclosed by the…
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from article Wood anatomy
Structure of a typical hardwood. (Credit: U.S. Department of Agriculture)
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from article Wood anatomy
Structure of a typical softwood. (Credit: U.S. Department of Agriculture)
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from article Arales
Anthurium andraeanum (flamingo lily). (Photo courtesy of Forest and Kim Starr)
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from article Potato, Irish
Irish potato (Solanum tuberosum). (Photo by Peggy Greb, Agricultural Research Service, U.S. Department of Agriculture)
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from article Potato, Irish
Diagram of a potato plant. [Adapted from R. E. Thornton and J. B. Sieczka (eds.), Commercial Potato Production in North America, Potato Association of America, Orono, ME, 1980]
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from article Potato, Irish
Irish potato tubers infected by late blight (Phytophthora infestans). (Photo by G. D. Franc; Bugwood.org)
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from article Persian melon
Persian melon (Cucumis melo). (Photo by Mehrdad Aref-Adib)
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from article Redwood
Redwood trees (Sequoia sempervirens). (Photo courtesy of Forest and Kim Starr)
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from article Euglenophyceae
Euglena sp., showing overall morphology and intracellular structures.
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from article Hypodermis
Transection from the outer part of a Smilax root, illustrating a thick-walled hypodermis (exodermis) beneath the epidermis. One hypodermal cell is not thickened. (After K. Esau, Plant Anatomy, 2d ed., John Wiley and Sons, 1965)
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from article Plant cell wall
Stylized model of the plant primary cell wall, showing layers of semicrystalline cellulose microfibrils associating with cross-linking hemicellulose polymers, embedded in a pectin matrix. (Copyright © McGraw-Hill Education)
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from article Plant cell wall
Light microscopy image of the outer cell layers and cuticle of a tomato fruit. The cuticle in this organ, shown here with a red stain, forms an exceptionally thick lipid coating on the outer epidermal cell and also permeates into the underlying cell…
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from article Plant cell wall
Model showing the multiple layers that can be observed in some secondary cell walls, which vary in the direction that the constituent cellulose microfibrils are deposited. (Copyright © McGraw-Hill Education)
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from article Plant cell wall
Cell expansion. (a) Two cells (left) of similar size, but different orientations of microfibril deposition show contrasting directions of cell expansion (right). (b) Model of the deposition of cellulose microfibrils by cellulose synthase complexes,…
Image
from article Sycamore
Leaves of the American sycamore (Platanus occidentalis). (Photo courtesy of Larry Allain, USGS National Wetlands Research Center)
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from article Sexual dimorphism
The enormous tail of the peacock (Pavo cristatus) is an obvious sexual dimorphism. Males display their colorful tail feathers to attract a female mate. (Credit: Dennis Jarvis)
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from article Sexual dimorphism
Northern elephant seals (Mirounga angustirostris) exhibit sexual dimorphism, especially large differences in size. The smaller seal is an adult female, whereas the much larger one (with the trunklike nose) is an adult male. (Credit: Jan…
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from article Sexual dimorphism
The male mallard duck (Anas platyrhynchos) has iridescent plumage to woo females, whereas the female's plumage is drab and inconspicuous. (Credit: U.S. Fish and Wildlife Service)
