Evolutionary Relationships
Learning about the relationship of plants involves the Protista. The protista kingdom is made up of dino• study of plant fossils (paleobotany), physical character• flagellates (Pyrrophyta); golden algae, yellow-green istics (anatomy), form (morphology), inheritance algae, and diatoms (Chrysophyta); and other organ• (genetics), chemical characteristics (physiology and isms. The Protista organisms are eukaryotic and usually plant biochemistry), and plant communities (ecology). one-celled. They often exhibit characteristics of both Carolus Linnaeus (1707-1778) organized a system, plants and animals. Nourishment is obtained by inges• which has since been expanded, for the classification tion, absorption, or by photosynthesis in plastids (see of plants on the basis of their evolutionary relation• 3). ships. Some groups of organisms studied by botanists are now not recognized as plants, for example, bacte• Plantae. Members of the plantae kingdom (plants) are ria, blue-green algae, fungi, and lichens. They are stud• red algae (Rhodophyta); green algae (Chlorophyta); ied by specialists on bacteria and blue-green algae brown algae (Phaeophyta); stone worts (Charophyta); (microbiologists), fungi (mycologists), and lichens liverworts, horn worts and mosses (Bryophyta); (lichenologists). horsetails and scouring rushes (Equisetophyta); ferns (Polypodiophyta); and plants bearing seeds. Seed-bear• Whittaker System of Kingdoms ing plants include the gymnosperms (= naked seeds) and the angiosperms (= enclosed seeds). Living gym• Monera. The monera kingdom consists of bacteria, nosperm groups are cycads (Cycadophyta), Ginkgo blue-greens (Cyanobacteria), and other microorga• (Ginkgophyta), conifers (Pinophyta) and gnetes (Gne• nisms such as viruses. In the past, blue-greens were tophyta). The angiosperm group consists of flowering grouped with algae. Now it is known that they are plants (Magnoliophyta). Plant nourishment is obtained more like bacteria. The cells of bacteria and blue• mainly by photosynthesis. greens do not have organelles; instead, the cell mem• branes carryon many biological functions. There is no Evolutionary Relationships membrane-bound nucleus; instead, hereditary material (DNA) is contained in fibrils in the central area (see 43). Dashed lines on the chart separate the kingdoms, while This type of cell is called prokaryotic, as opposed to a solid lines show probable evolutionary lines. The living true or eukaryotic cell (see 2). groups shown are those discussed in this book. Living groups that are not discussed are omitted from the Fungi. The fungi kingdom includes slime molds (Myxo• chart. Shaded groups are extinct. The origin of flow• my cot a); water molds, downy mildews and white rusts ering plants is not yet known. (For a modified classifi• (Oomycota); and true fungi. True fungi include chytrids cation system of all living organisms see the Whittaker and allies (Chytridiomycota), black bread mold and and Margulis reference and for an explanation of evo• allies (Zygomycota), sac fungi (Ascomycota) and club lutionary relationships see the Stebbins reference in the fungi (Basidiomycota). bibliography.)
COLOR CODE blue: monera groups tan: fungal groups yellow: protista groups gray: extinct groups (shaded) green: living (extant) plant groups
41
J. Glimm-Lacy et al., Botany Illustrated © Janice Glimm-Lacy and Peter B. Kaufman 1984 Plantae
Protista
Monera
Evolutionary Relationships Geologic Time Scale
Time Units and blue-green algae are found. The earliest eukaryotic cells are from rocks about 1,000 million years old. Eras. The largest units of geologic time are known as These fossils are rare, and the early evolutionary his• eras; each encompasses millions of years. They are tory of non-vascular plants is obscure. In the late Silu• basically defined by biological events - the appearance rian period, the first vascular plants appear. or disappearance of major groups of organisms. These changes in biology are related to major geologic The groups indicated on the chart are vascular plants, events, but only the biologic changes are seen world• meaning they had specialized conducting tissues of wide in the fossil record. xylem and phloem. The size of the plant groups reflects their relative abundance in time. Two groups are Periods. Each era is subdivided into periods, and the extinct and are known only from their fossil record. periods are broken down into epochs; again their sep• arations are most commonly based on fossils. Land plants became abundant during the Devonian period. During the Carboniferous (Mississippian and Fossil Record and Appearance of Vascular Plants Pennsylvanian periods), there were vast forests of trees and swamps preserved now as coal. The Jurassic About 85% of earth's geologic time is within the Pre• period of the Mesozoic era was the "age of cycads" cambrian era. The division that marks the end of Pre• and was a time when conifers were distributed world• cambrian time and the beginning of the Paleozoic era, wide. Primitive flowering plants evolved during the about 600 million years ago, is recognized by the Cretaceous, and by the Tertiary period of the Ceno• worldwide appearance of fossils of invertebrate zoic they dominated the land. Later, grasslands were marine animals. In the Precambrian, in rocks over 3,000 apparent and the landscape has been dominated by million years old, the first fossil organisms of bacteria herbaceous flowering plants ever since.
COLOR CODE
gray: extinct plant groups green: living (extant) plant groups
42 Flowering Plants
,.----L..-- Seed Ferns ~ I------V Cycads i'- -- Seed Plant Gnetes I Ancestors-- ...... 1 -I --- Conifers r-- --- ...... Ginkgophytes
...- Ferns r--
.- Horsetails - ...... Scouring Rushes_"'-
.... ---. Clubmosses, Spike mosses, Quillworts r-- _r---
0 c 00 c c 'c'" :l '" C C 'a' '" ~ '0 '" > 0 '" a. '" c u
Geologic Time Scale Bacteria
Bacteria have existed for billions of years, and with a that derive their energy from the sun are called pho• wide range of species that have become adapted to all totrophs (= light nourishment). In contrast, those that kinds of environments, they can live almost every• derive their energy from the chemical environments where on earth. are called chemotrophs (= chemical nourishment). Phototrophs and chemotrophs are further subdivided Bacterial Cell according to whether the electrons they donate for respiration or fermentation come from organic com• A bacterium is an aquatic micro-organism (1 to 10 pounds or inorganic compounds; thus, the photo• micrometers in size; 1 micrometer = 0.000039 inch). trophs are classified as either photoorganotrophs or Its prokaryotic cell consists of a protoplast of cyto• photolithotrophs. Likewise, chemotrophs are classified plasm (a) within a plasma membrane (b). Irregular as either chemoorganotrophs or chemolithotrophs. infoldings of the plasma membrane are called meso• somes (c), which are involved in many cell functions, Of interest .,. ecosystem: bacteria are the major such as division, nuclear segregation, respiration, and decomposers, breaking down organic materials into secretion. In the cytoplasm are ribosomes (ribonucleo• simpler substances; nitrogen-fixing: Spirillum lipoferum, protein particles, d), a nucleoid (DNA-bearing struc• Rhizobium radicicola, and Bacillus radicicola, which ture, e), and some have photosynthetic pigments. Sur• occur in root nodules of higher plants, convert atmo• rounding the protoplast of most bacteria is a rigid cell spheric nitrogen into ammonia and amino acids (see wall (g). Some bacteria also have an outer slime layer 12); health: a microflora of bacteria maintains health in or capsule (h). No flagella or up to 30 flagella may be all organisms; industry: manufacture of cheese, vine• present. Each flagellum (i) is made up of fibers of pro• gar, butyl alcohol, acetone, antibiotics (streptomycin, tein. The flagella are involved in cell movement. Some aureomycin, chloramphenicol); retting of plant fibers; bacterial types form a resistant endospore (D. The most sewage disposal; research: most biochemistry research common bacterial forms are spherical (coccus), rod• systems use bacteria; bacteria are used in modern shape (bacillus), and helical (spirillum and vibrio). With genetic engineering; some photosynthetic bacteria can a crystal violet staining procedure (Gram stain), all bac• convert carbon dioxide to chains of hydrocarbons teria can be divided into two large groups: Gram pos• (crude oil); human diseases: a very small percentage of itive and Gram negative. the bacteria of the world cause diseases such as scarlet fever, typhoid, diptheria, tuberculosis, botulism, chol• Cell Wall era, syphilis, gonorrhea, tetanus, anthrax, bubonic plague, leprosy, gangrene, meningitis, tularemia, and The rigid cell wall is characteristic of plant cells (animal some forms of dysentery and pneumonia; plant dis• cells are bound by a thin membrane). Materials must be eases: wilt disease of potato, cucumber, tomato; citrus dissolved in water in order to pass through the cell canker; fire blight of pear and apple trees, crown rot wall. The bacterial cell wall makes up 20 to 40% of the of cabbage and carrots. cell weight and contains chemical substances found only in bacteria and blue-greens.
Classification
Bacteria are most conveniently classified according to how they obtain their energy for metabolism. Those
COLOR CODE red: nucleoid area (e) black: ribosomes (d) yellow: cytoplasm (a) blue: peri plasmic space (f) tan: cell wall (g), bacterial forms white: capsule (h)
43 a h b .+-+--g
d e
"Typical" Prokaryotic Cell diagram
o
coccus diplococcus streptococci (sphere-shape) (2 spheres) (chain of cocci)
staphylococci sarcinae bacillus (cluster of cocci) (4 cocci) (rod-shape)
.; ~ C)) bacillus spirillus vibrio (with flagella) (spiral-shape) (comma-shape)
Common Bacterial Forms Blue-greens: Cyanobacteria
Fossil history of the blue-greens extends back in the onizers on bare soil and rock; by forming mats that Precambrian era. They are found in water, in and on bind to the soil surface, they reduce soil erosion. As soil, on rocks, and in the atmosphere. Habitat temper• nitrogen-fixers, they contribute to soil fertility (growing atures range from 0° to 85°C. Some species occur in in rice paddies, Anabaena, in association with the float• lichens, liverworts, water ferns, cycads, and flowering ing water fern, Azalia, 70, increases rice production). plants as symbionts. Blue-greens contribute to the water plankton food chain; toxins: "blooms" of dense concentrations in the Characteristics. The microscopic blue-greens have no sea kill marine fish, and in reservoirs, they may cause membrane-bounded nucleus (prokaryotic). The cell has gastrointestinal diseases in cattle and humans. a mucilaginous sheath that surrounds the cell wall. Cell contents (protoplasm) include nuclear material with Synechococcus DNA fibrils, chlorophyll a, and accessory pigments of blue (phycocyanins), red (phycoerythrin), and orange Structures of this unicellular blue-green include a muci• (carotenes) colors. The pigments are involved in cap• laginous sheath (a), cell wall (b), plasma membrane (c), ture of light and subsequent formation of carbohy• and protoplasm (d). drates (photosynthesis). Blue-green forms may be one cell (unicellular), colonial (cells held together by a gelat• Cylindrospermum inous sheath), or filamentous (chains of cells called tri• chomes). They have no thread-like structures (flagella) This filamentous blue-green has an akinete (e) and a for movement. heterocyst (f) at the end of the trichome.
Reproduction. Blue-greens have no known sexual Anabaena reproduction. Reproduction of unicellular forms is by cell division in which the cell wall folds in and "pinches" This genus is a frequent part of water "blooms." A het• the cell into two cells. Colonial and filamentous forms erocyst (g) is located near the center of the trichome. fragment into separate pieces. Filamentous forms have various specialized cells: an akinete is a resistant cell Gloeotrichia filled with food reserves, which can germinate to form a new filament; a transparent heterocyst functions in Colonies of trichomes are formed. The trichome has a nitrogen-fixation, and is located where the filament heterocyst (h) and an adjacent akinete (i). breaks. Some genera have exospores, cells that pinch off the filament. Hapalosiphon
Of interest ... ecosystem: blue-greens are primary col- The trichome is branched, with a heterocyst (j) present.
COLOR CODE
white: sheath (a), heterocyst (f, g, h, j) tan: wall (b) blue-green: protoplasm (d) dark blue-green: akinete (e, i)
44 Blue-green Forms
'>----..+-- b
,:·!\.-l~--.\---c
'-'--'-~---l--d Cylindrospermum filamentous X 450
Synechococcus unicellular diagram of structures Anabaena filamentous X 450
d
d h
Cloeotrichia Cloeotrichia colonial diagram of colony X 450 Hapalosiphon filamentous X 450 Slime Molds: Myxomycota
Even in the days when organisms were grouped as ber of nuclei, which divide simultaneously; engulfing either plants or animals, no one knew what to do with food; and eventually, converting into fruiting bodies the slime molds. The creeping acellular phase is animal• called fructifications. The three types of fructifications like, while the reproductive structures that produce formed by various species are sporangia, aethalia, and spores are plant-like. Now, true slime molds are rec• plasmodiocarps. A sporangium may have a stalk (h) or ognized as a separate group, but are studied by fungal not, with a base called a hypothallus (i), and a wall of specialists, the mycologists. Slime molds probably orig• varying lime content, the peridium (g), to enclose the inated from protozoan-like ancestors. spores. Inside the peridium may be a non-living net• work of hairs, capillitium (f), to aid in spore distribution. Characteristics. There are about 450 species of slime An aethalium is cushion-shaped with a peridium (0) molds, distributed worldwide. Most live in shady moist enclosing the spores. The third type of fructification is woods on decaying wood, leaves, or moss. Some a plasmodiocarp, which retains the net-shape of the occur in open, but moist areas, such as lawn grass. plasmodium. By reduction division (meiosis), 1n spores Their diet is bacteria, protozoa, fungal spores, and are produced. With favorable conditions, the spore other minute organisms. The body of the slime mold is germinates into a myxamoeba without flagella, or a called a plasmodium (a), consisting of a membrane cov• swarm cell with flagella. These cells function as sex cells ering, without cell walls, and containing many nuclei. (gametes). Two cells fuse to form a 2n zygote nucleus, Some plasmodia move in an amoeba-like fashion, flow• which divides mitotically to develop into a ing over surfaces, engulfing nutrients. When tempera• plasmodium. ture or moisture conditions are unfavorable, the plas• modium converts to a hardened mass in a resting Of interest ... blue lawn infestation: Physarum ciner• dormant condition called a sclerotium (b). eum; research material: slime molds provide pure, cell• less protoplasm for genetic, developmental, and can• Reproduction. The life cycle consists of the plasmo• cer studies; ecosystem: primary decomposers in the dium fusing with other plasmodia, increasing the num- forest food chain.
COLOR CODE
yellow: plasmodium (a), sclerotia (b) yellow-brown: dried plasmodium (c), capillitium (f) gray: stalk (d), peridium (e) tan: peridium (g), wood (y) dark brown: stalk (h), hypothallus (i) brown: spores (j) black: stalk (k) white: lime dots on peridium (I), hypothallus (v), stalk (w) dark brown: peridium (z, p), stalk (m, q) green: moss (n) pink: peridium (0) orange-brown: hypothallus (r), stalk (s), peridium (t), capillitium (u) iridescent (dots of green, red, yellow): peridium (x) orange: plasmodiocarp
45 Slime Molds
e b
Physarum Physarum Physarum sporangium sclerotia plasmodium toplasmic flow arrows indicate pro X 10 X 10 magnified
z
Hemitrichia Stemonitis Didymium sporangia sporan-gia sporangia X 10 X 3 X 10
o x
Lycoga/a Diachea aethelia sporangia X2 X 10
u s
Dictydium sporangia X 20 Arcyria Hemitrichia sporangia plasmodiocarp X 10 X 10 Fungi: Oomycota, Chytridiomycota
Fungi Aphanomyces (root disease of sugar beets, peas), Phy• tophthora infestans (potato blight), Plasmopara viticola Characteristics. Fungi are organisms without chloro• (downy mildew of grapes), Pythium debaryanum phyll and, therefore, are dependent on other organ• (damp-off of seedlings), Saprolegnia (disease of fish isms for nutrition. A saprophytic fungus obtains food eggs and fish). from dead organic matter. A parasitic fungus feeds upon a living organism, the host. Symbiotic fungi live in Achlya a mutually beneficial relationship with a host. A fungus associated with roots of a higher plant, called a mycor• The water mold illustrated here has male and female rhizal association, may be parasitic or symbiotic (see individuals. Eggs (a) are produced in an egg chamber 12). Fungi range in size from one-celled, microscopic (oogonium, b) on the hypha (c). From a male, individual organisms to masses of cells strung together in long fila• antheridia (d) branch from a hypha (e). After fertiliza• mentous strands. Each strand is called a hypha (pI. tion by a male gamete from the antheridium, an egg hyphae). The mass of hyphae that make up a fungal develops into a 2n oospore (f). The oospore germi• body is called mycelium. nates and forms a new fungal body of hyphal strands (g), which produces biflagellated zoospores (h). Reproduction. All fungi bear spores. The microscopic lower fungi mainly live within a host and reproduce Chytridiomycota (Chytrids and Allies) mostly by asexual spores. Higher fungi have elaborate fruiting bodies, composed of hyphae, in which spores These simple, microscopic fungi live in water and soil. are borne. Sexual reproduction, the basis of fungal clas• They may be one cell living within a cell of a host alga sification, is commonly once a year. Those fungi in or higher plant or have true mycelium and live on the which a sexual stage has not been found are classified surface of a host. The motile cells have one whiplash as Fungi Imperfecti (Deuteromycota). flagellum.
Oomycota (Water Molds, Downy Mildews, White Of interest ... Some fungal parasites destroy algae, Rusts) some are parasitic on economic plants such as Physo• derma (brown spot of corn), Synchytrium (black wart In this division, fungi are microscopic and found in disease of potato tubers), Urophlyctis (crown wart of water and soil. The most advanced forms live entirely alfalfa). within a plant or animal host. The fungal body may range from one cell to copious amounts of mycelium. Allomyces Reproduction is by oospore, a sexually produced, non• motile cell; and, asexually, by zoospores with two The 2n mycelium of this fungus produces thin-walled, unlike flagella for motility. This group is generally spore-bearing structures called sporangia on hyphal regarded as more plant-like than other fungi since the strands (i). From a sporangium (j), 2n spores (k) emerge. cell wall contains cellulose but lacks chitin. The cell Other, thick-walled sporangia (I) produce 1n spores (m) walls of all other fungi contain chitin. by meiosis. A 1n spore germinates into a 1n hypha (n), which produces 1n sex cells (gametes, 0, p) in gam• Of interest ... Albugo spp. (white rust of horse-radish, etangia (q). Fusion of unlike gametes into a zygote (r) cabbage, sweet potato, morning glory, spinach), results in the germination of spore-bearing hyphae (i).
COLOR CODE
pink: egg (a), gamete (0) gray: oogonium (br, hypha (c, e, g, i, n) blue: antheridia (d), gamete (p) purple: oospore (f), zygote (r) yellow: zoospores (h, k, m) colorless: sporangium (j, I), gametangia (q)
46 lower Fungi Achyla Water Mold reproduction c
hypha with antheridia
hypha with oogonia
oospore
Allomyces 6 Chytrid -- reproduction 1 n spores hypha with gametangia
o
p
. j
gametes
hypha with sporangia zygote Fungi: Zygomycota; Sac Fungi: Ascomycota
Zygomycota (Black Bread Mold and Allies) Hemiascomycetidae. Members of this group have little or no mycelia and the asci are not produced in a spore• Fungi in this division are defined by their sexual resting bearing structure or fruiting body. Yeasts have evolved spores (zygospores). Another characteristic is the asex• from several evolutionary lines, but are grouped ual, non-motile, reproductive spore. together for convenience. They are found in sugary substances such as flower nectar and on the surface of Of interest ... Rhizopus stolonifer (black bread mold, fruits, in soil, in animal wastes, in milk, and in other sub• strawberry leak, sweet rot of potatoes), Choanephora stances. They have the ability to ferment carbohy• cucurbitarium (squash flower and fruit mold); Absidia drates, producing alcohol and carbon dioxide. The leaf• sp., Mucor spp., Rhizopus sp. (fatal to human nervous curl fungi are classified with the yeasts, as both may system). form buds on the ascospores. Of interest ... Saccharomyces cerevisiae (baker's and Mucor brewer's yeast), Taphrina spp. (leaf curl of peach, chokecherry, oak; witch's broom of cherries). Hyphae (a) of compatible mating types develop side branches (b) that meet. A swelling or progametangium Saccharomyces cerevisiae Yeast (c) is produced at each side. The walls (d) between the two break down. The nuclei from each progametan• Yeasts are microscopic, unicellular organisms (i). Asex• gium fuse together and form a zygospore (e) held by ual reproduction is by cell division and budding (j). Sex• suspensors (f). ual reproduction, while rare, is by fusion of two cells to form an ascus (k) of 4 ascospores (I). Ascomycota Taphrina deformans Peach leaf Curl Fungi in this division sexually produce usually 4 or 8 ascospores (g) within a sac sporangium called an ascus Budding spores infect the peach leaf (m) producing (h). Asexual reproduction is by breaking off (fragmen• more buds or mycelium, which penetrates the leaf tis• tation) of mycelium, by splitting of one cell into two sue. The host tissue reacts to this infection by forming cells (fission), by the budding of cells, and by formation swollen, tumor-like masses (n) and by tortuous curling of conidia. of the leaves.
COLOR CODE
gray: hypha (a), tips (b), progametangium (c), zygospore (e), suspensors (f) yellow: ascospore (g, I) beige: cell (i, j) colorless: ascus (h, k) brown: masses (n) green: leaf (m)
47 Lower Fungi Sac Fungi
Ascus sac sporangium with 8 ascospores
h
c
Saccharomyces cerevisae Yeast
d
e m
Typhrina deformans Peach Leaf Curl Mucor on peach leaf zygospore formation X 1 Molds, Mildews, Morels: Ascomycota
Euascomycetidae. Usually, members of this group Morchella Morel have asci enclosed in a fruiting body called an asco• carp. A cleistothecium, a perithecium, and an apothe• Easily recognized, this edible mushroom is prized for its cium are types of ascocarps. A cleistothecium (c) is an distinctive flavor. Apothecia with asci line the cavities enclosed ascocarp composed of loose masses of (k) of the spongy-looking fruiting body (I). Colors of hyphae with asci irregularly arranged within. A peri the• species range from white to beige to dark brown. cium (h) is a vase-shaped ascocarp with a pore (ostiole, i) at the top. It may be embedded in a compacted C/aviceps purpurea Ergot of Rye mycelial structure (stroma, j). An apothecium is a cup• shaped ascocarp with asci lining the open surface (see An ascospore germinates into a mat of mycelium on a 54). rye flower (see 123). Instead of a rye grain (m) devel• oping, the fungal mycelium forms an overwintering, Of interest ... molds: Aspergillus spp. (mold on bread, asexual mass - a dark, hardened sclerotium (n). This leather; causes human skin and respiratory disease), sclerotium contains alkaloids that poison cattle when C1aviceps purpurea (ergot of rye), Neurospora (pink grazing and humans when eating contaminated rye bread mold), Penicillium spp. (green mold on citrus flour products. fruits and preserves, blue mold for cheese production of Roquefort, Blue, Camembert, Gorgonzola; anti• Xylaria Dead Man's Finger biotic); wilts: Ceratocystis spp. (oak wilt, Dutch elm dis• ease); blight: Endothia parasitica (chestnut blight); pow• Perithecia are embedded in the outer wall of the dery mildews: Chaetomium (of clothes), Podosphaera stroma (0) or "finger," which develops on rotten, leucotricha (of apple), Sphaerotheca pannosa (of burned wood. Mycelial filaments (p) are shown. roses); rot: Monilinia fructicola (brown rot of stone fruits); wild: Helvella and Cyromitra (false morels), Daldinia concentrica Morchella (morel), Tuber (truffle), Verpa (bell morel). A vertical section reveals perithecia (q) lining the outer stromatic surface (r) of this cushion-shaped fruiting Penicillium body. Asexual reproduction is by microscopic spores called conidia (a) formed on the side of a hyphal strand (b). Geoglossum difforme, Microglossum rufum Earth Tongues Microsphaera alni Powdery Mildew of Lilac Apothecia of asci form on the surface of the club• The microscopic fruiting body is a cleistothecium. The shaped fruiting bodies (s, t). wall (c) has been broken to reveal 2 asci (d) with asco• spores (e). Appendages (f) aid in spore dispersal.
Diatrypella COLOR CODE
In this fruiting body, asci (g) line perithecia (h) with ter• yellow: conidia (a), ascospore (e), ascus (g) minal pores (i). They are embedded in a stroma (j). colorless: ascus (d), pores (i), filaments (p), perithecium (q) gray: hypha (b), perithecium (h), stroma (0) black: wall (c), stroma (j), fruiting body (5) white: appendages (f) beige: fruiting body (k, I) gold: grain (m) dark brown: sclerotium (n), stalk (u) purple: stroma (r) orange-red: fruiting body (t) green: moss (v)
48 Microsphaera alni Sac Fungi Powdery Mildew c1eistothecium X 320
k
Penicillium .. "brush" of cOnidia
Diatrypella fruiting bod~ g vertical section Morchella X 90 Morel fruiting body X 1
iii .\: , ~ \:~ ''''. &-d?.
. ncentrica Daldima co I"ical section fruiting body, ver. X 1
Ceoglossum dlf
Xylaria Dead Man's Finger fruiting bodies X 1
C1aviceps p urpurea Ergot Fungus sclerotia on rye X 1 Microglossumrufum Earth T ong~e fruiting bodies X 1 Rusts, Smuts, Jelly Fungi: Basidiomycota
Basidiomycota Of interest ... Usti/ago spp. (smut of corn, oats), Uro• cystis cepu/ae (onion smut), Tilletia foetia (bunt or stink• For fungi in this division, sexual reproduction results in ing smut of corn). usually 4 basidiospores (a) produced on the outside of a club-shaped sporangium called a basidium (b). When Urocystis cepulae Onion Smut basidia are borne in a fruiting body, it is called a ba• sidiocarp. Familiar forms are mushrooms, shelf fungi, Black teleutospores (f) form an infestation on onions and puffballs. There are many edible species; however, (g). there are no rules, only myths, for distinguishing poi• sonous from edible fungi. Auriculariales (Jelly Fungi). Fruiting bodies of gelati• nous material are produced; when wet, basidia are Uredinales (Rusts). Fungi in this order are obligate par• formed. Most genera are saprobic, living on dead asites (require living hosts). No fruiting bodies are pro• organic matter. A few genera are parasitic on mosses duced. Classification is by teleutospore, representing and flowering plants. the overwintering, resting stage. Many rusts attack only specific plants; some require two hosts to complete Of interest . .. Herpobasidium deformans (blight of their life cycles. For example, wheat rust alternates honeysuckle). between wheat and barberry. Auricularia auricula Of interest ... Puccinia spp. (rust of wheat, barley, Ear Fungus oats, rye, hollyhock), Cronartium nbico/a (white pine The gelatinous fruiting body (h) resembles an ear. blister rust), Cymnosporangium spp. (rusts of juniper, apple, hawthorn, pear). Tremellales (Jelly Fungi). Fruiting bodies are gelatinous, leaf-like folds and vary in color with species from Gymnosporangium juniperi-virginianae white, pink, yellow, and orange to red.
The life cycle of this fungus is completed by alternation Tremella mesenterica between apple and red cedar plants. The cedar apple gall (c) is a mass of mycelium on cedars (d). During This jelly fungus (i) is found on hardwood bark (j). Some spring, gelatinous structures, telia (e), expand with species are edible. water and protrude from the surface. Inside a telium are hundreds of teleutospores, basidial structures, Dacrymycetales (Jelly Fungi). Waxy, bright-colored, which produce basidiospores after germination on gelatinous fruiting bodies are produced. apple trees.
Ustilaginales (Smuts). Smuts form masses of black, Dacryopinax spathularia sooty-looking teleutospores. Smuts are similar to rusts This jelly fungus (k) is found on rotting wood (I). but do not need living host material and can be grown in the laboratory.
COLOR CODE
yellow: basidiospore (a), onion (g) tan: basidium (b), fruiting body (h) orange: telium (e), fruiting body (k) brown: gall (c), wood (I) green: cedar (d) pale yellow: fruiting body (i) gray: bark (j) 49 Club Fungi
Basidia with basidiospores X 450 Basidiocarp gill section
Cymnosporangium gall on cedar X 1
d
Tremella mesenterica Jelly Fungus fruiting body Xl
Urocystis cepulae Oacryopinax spathularia Onion Smut Jelly Fungus on onion fruiting body X 1 X 1 Gill Fungi: Basidiomycota
Agaricales (Gill, Pore, Coral, and Toothed Fungi). In this order, a basidium usually produces 4 basidio• spores, which are forcibly discharged from the fruiting body. Fruiting bodies may be in forms commonly known as mushrooms, toadstools, shelves, corals, and toothed fungi. A "spore print" (basidiospore collec• tion) can be made by placing a fruiting body cap with gills or pores half on white paper, half on black paper. Spore color, useful for identification, is white, pink, yel• low, brown, purple, or black.
Of interest ... food: Agaricus campestris (commercial mushroom); wild: Amanita verna (destroying angel), Armillaria mellea (honey mushroom, causes root rot of trees, exhibits bioluminescence or "fox-fire" in myce• lia-penetrated organic matter), Canoderma applana• tum (artist's fungus), Marasmius oreades (fairy ring mushroom), Pleurotus ostreatus (oyster mushroom), Polyporus sulphureus (sulfur mushroom, causes wood rot of trees), P. squamosus (heart rot of trees), Psilo• cybe spp. (hallucinogenic mushrooms).
Amanita muscaria Fly Amanita, Fly Agaric
The fruiting body of a gill mushroom begins as a mass of hyphal cells and enlarges into a "button." At this stage, the fruiting body is surrounded by a universal veil (d). As expansion of the gills (lamellae) takes place, the veil is broken. The veil may remain as patches or scales (b) on the cap (pileus) and as veil remnants (c) or as a cup (volva) at the base of the stalk (stipe). Some species of agarics also have an inner or partial veil (d) between the developing stalk (e) and gills (f). When the partial veil is broken at expansion of the gills, it may remain attached to the stalk as a ring (annulus, g) or remain attached to the margin of the cap, hanging down as a curtain as in Cortinarius. The microscopic basidia are borne on the inner surface of the gill. Indi• vidual cap (h) color in this species varies from white, yellow, and orange to red. This is a poisonous mush• room, found mostly in mycorrhizal association (see 12) with roots of aspen and conifer trees.
Cortinarius COLOR CODE
Remains of the partial veil, which hung down from the white: scales (b), veil remnants (c), partial veil (d), stalk (e), gills (f), annulus (g) cap as a curtain (cortina), form web-like lines (i) on the orange-red: cap (h) stalk (j). As the cap expands, gills (k) are exposed. This light tan: stalk (j), gills (k) fruiting body was found in a beech-maple forest. yellow: cap margin (I) yellow-brown: cap center (m) 50 m Club Fungi
1I1~"--- k b
h
Cortinarius fruiting body e X 1
c
e Fruiting Body X 1
a Fruiting Body cap, vertical section X 1
Fruiting Body button stage Amanita muscaria vertical section Fly Amanita X 1 Gill and Pore Fungi: Basidiomycota
Agaricales (continued).
Coprinus comatus Shaggy Mane
As the white fruiting body matures, the gills undergo self-digestion with black basidiospores released in an inky black fluid. This mushroom is found in lawns and fields.
Chantharellus cinnabarinus Cinnabar Chanterelle
Basidiospores are produced on blunt gills (b). With age, the cap (c) becomes funnel-shaped on the fruiting body stalk (d).
Russula emetica Emetic Russula
The fruiting body has a stout stalk (e) supporting a bright red cap (f) with white, brittle gills (g).
Sui/lus amet:lcanus
Instead of gills, this bolete has fleshy pores (h). Basidia line the inner surfaces of layers of tubes wLth pore openings. The fruiting body is fleshy and decays quickly. Brown scales (i) dot the cap (j).
COLOR CODE
light tan: veil remnant (a) dark orange: gills (b), cap (c), stalk (d) pale pink: stalk (e) red: cap (f) white: gills (g) yellow: pores (h), cap (j), stalk (k) brown: scales (i) green: moss (I)
51 Club Fungi
g e
Chantharellus cinnabarinus Cinnabar Chanterelle Russula emetica fruiting bodies Emetic Russula X 1 fruiting body X 1
_<----- c
/W-'------b c
d
Suillus americanus Coprinus comatus Bolete Fungus Shaggy Mane fruiting body fruiting bodies X 1 X 1 Pore, Coral, and Toothed Fungi: Basidiomycota
Agaricales (continued).
Coriolus versicolor Turkey-tail Fungus
In polypore (= many pores) fungi, basidia are formed on the inner surface of leathery pores (a) on the lower portion of the fruiting body (b).
Fomes formentarius Rusty-hoof Fornes
This perennial polypore adds new growth (c) yearly to the shelf-type fruiting body (d) found on birch and beech (e) trees.
Irpex lacteus Crust Polypore
A crust-like fruiting body (f) of this polypore grows on the lower surface of dead tree limbs (g).
Ciavulinopsis fusiformis Coral Fungus
The fruiting body (h) in this coral fungus is simple and unbranched.
Ramaria stricta Straight Coral Fungus
This coral fungus has a more complexly branched fruit• ing body (i).
Hericium Toothed Fungus
Basidia are produced on downward-pointed, tooth-like projections on the fruiting body (j).
COLOR CODE
tan-brawn-white bands: fruiting body (a, b) rust (yellow-brown-red): new growth (c) dark and light gray bands: fruiting body (d) brown: bark (e) yellow-tan: fruiting body (f, i) gray: bark (g) orange: fruiting body (h) white: fruiting body (j) 52 Club Fungi
d b
c
r",...... -e I I Coriolus versicolor Turkey-tail Fungus Fomes fomentarius fruiting body Rusty-hoof Fungus X 1 fruiting body XJ2
/rpex lacteus Crust Polypore fruiting body X 1 h
Ramaria stricta Straight Coral Fungus fruiting body X 1 Clavulinopsis fusiformis Coral Fungus fruiting body X 1
Hericium Toothed Fungus fruiting body X 1 Puffballs, Stinkhorns, and Bird's-nest Fungi: Basidiomycota
Lycoperdales (Puffball Fungi). Spores are dispersed by rus (net stinkhorn), Mutinus (dog stinkhorn), Phallus wind from puffball fruiting bodies. An inner fertile por• (common stinkhorn). tion, called the gleba, is composed of basidiospores and sterile thread-like structures (capillitia). Spores are Dictyophora duplicata Collared Stinkhorn exposed when the puffball wall (peridium) disinte• grates, or emerge in a cloud from an opening (ostiole) At the egg stage, the peridium (g) encloses the gleba when the flexible peridium is disturbed. (h) where basidia and basidiospores are formed. The receptacle (i) and stalk (j) will enlarge and emerge from Of interest ... Calvatia gigantea (giant puffball), Ceas• the peridium, which remains at the base. trum and Astraeus (earthstars), Lycoperdon (stalked puffball). Mutinus caninus Dog Stinkhorn
Geastrum Earthstar From the broken peridium (k), a pink stalk (I) emerges. The dark pink receptacle (m) at the top of the fruiting A rigid outer wall or peridium (a) splits to expose an body is covered in a green, slimy gleba (n) of spores. inner flexible peridium (b) with an ostiole (c) for spore dispersal. Nidulariales (Bird's-nest Fungi). The fruiting body appears as a hollow nest filled with egg-like peridioles, Lycoperdon Stalked Puffball which contain basidiospores. The nest acts as a splash• cup. Raindrops cause the peridioles to bounce out of At maturity, a powdery gleba of spores (d) puffs out of the fruiting body. The peridiole's sticky covering an ostiole (e) in the peridium (f) due to rain drops or adheres to nearby surfaces where the spores are then other disturbance. released.
Phallales (Stinkhorn Fungi). Basidiospores are formed Of interest ... Nidularia (white bird's-nest), Crucibulum within a gleba. A receptacle, bearing the gleba, (common bird's nest), Cyathus (striate bird's-nest). emerges from a protective enclosure, the peridium. As the gleba breaks down, the basidiospores are exposed Crucibulum vulgare Common Bird's-nest Fungus in a gelatinous mass at the top of the stinkhorn. The foul smell of the mass attracts flies, which disperse the This genus is often found on wood chip (0) paths and spores. on the forest "floor." Small peridioles (p) are formed in Of interest ... Dictyophora (collared stinkhorn), Clath- the nest-like fruiting body (q).
COLOR CODE
tan: peridium (a, b, f, g, q) green-brown: gleba (h, n) white: receptacle (i), stalk 0), peridium (k), peridiole (p) light pink: stalk (I) dark pink: receptacle (m) brown: wood chips (0) 53 c Club Fungi
d a
Ceastrum Earthstar fruiting body X 1
Lycoperdon Stalked Puffball ""---m fruiting body X 1
~Hl'll---m
\ 1 I Dictyophora duplicata I I Collared Stinkhorn I I fruiting body, egg stage vertical section Xl "'------
p o
k
Mutinus caninus Crudbulum vulgare Dog Stinkhorn Common Bird's-nest fungus fruiting body fruiting body Xl X 1 Lichens: Mycophycophyta
A lichen is an association of a fungus (mycobiont) and Of interest ... arctic animal food: Cetrarias, Cladonia an alga (phycobiont). The fungus is an ascomycete or a spp. (reindeer mosses), Usneas; human skin rash: Ever• basidiomycete; the algal partner is either a blue-green nias, Usneas; dye: Letharia, Ochrolechia, Parmelia, Roc• or green alga. The association can be parasitic, in which cella; ecosystem succession role: lichens are often the the fungus eventually kills the algal cells; or it can be first colonizers of bare substrata, breaking up rocks, mutualistic, in which both fungus and algal cells benefit. due to their secretions of lichen acids; thalli form an Mutual benefits include algal nutrition to the fungus and anchor base for later colonizing plants. fungal protection for the alga. Lichens can tolerate harsh conditions such as dryness, arctic cold, and bare Ascomycota: Euascomycetidae (Lecanorales) rock habitats, and possibly live thousands of years. Graphis scripta Script Lichen Characteristics. The upper cortex (a) is the outer pro• tective layer with fungal hyphae gelatinized and Found on hardwood trees, this crustose lichen thallus cemented together. Next is the algal layer (b). Most (f) has dark eruptions of apothecia (g). lichens are associated with the unicellular green alga, Trebouxia. So far, over 30 genera of algae have been Xanthoria found associated with lichens. Most of the lichen body (thallus) is made up of medulla (c) with hyphae loosely Found on rotten wood, the thallus (h) of this foliose interwoven. The medulla retains moisture and stores lichen has apothecia of grey-green receptacles (i) with food. The thallus may take different forms. Crustose brightly colored ascospore layers (hymenia, j). lichens are extremely flat and only ascocarps (see 49) may be visible. They are found on rocks and trees. The Physcia aipolia Blister Lichen medulla may be embedded in rock surfaces. Foliose lichens have a leafy thallus and may have a compacted This foliose lichen has a white-spotted thallus (k) with lower cortex (d) and root-like anchoring devices called apothecia emerging from the surface cortex. The fertile rhizines (e). Fruticose lichens with three-dimensional layer of asci (hymenium, I) is gray with a gray-green projections, called podetia, arise from a scale-like, receptacle (m). loosely-attached (squamulose) base. Cladonia cristatella British Soldiers Reproduction. Various vegetative structures may be found on lichens, such as soredia and isidia. 50redia The fruticose podetium (n) arises from a squamulose originate in the algal layer as masses of algae cells with thallus (0). Red apothecia (p) dot the top of the a few gelatinized hyphae erupting through cracks in podetia. the surface cortex. Breaking off, new lichen thalli are formed. An isidium is a projection on a foliose or fru• Cladonia pyxidata Pyxie Cup ticose lichen that serves as a vegetative propagule when broken off. Depending on the type of fungus, The fruticose podetia (q) resemble pyxie cups arising fruiting bodies with ascospores or basidiospores are from a squamulose thallus (r). Brown apothecia (s) dot produced. Lichens also have asexual reproductive the cup rims. structures called pycnidia, flask-shaped structures that. produce microconidia. The fungal spore or microconi• COLOR CODE dium must form an association with an appropriate alga to live. gray: cortex (a, d), thallus (f), hymenium (I) green: algae (b) white: medulla (c) black: rhizines (e), apothecia (g) gray-green: thallus (h, k, 0, r), receptacle (i, m), podetium (n, q) yellow-orange: hymenium (j) red: apothecium (p) brown: apothecium (s) 54 Lichens
a
b
c
Crustose, Squamulose
Lichen Structure diagrams
h--b ,;!\
g
Xanthoria foliose X7
crustose XS
Physcia aipolia Blister Lichen foliose X7
q n Cladonia cristatella Cladonia pyxidata British Soldiers Pyxie Cup Lichen fruticose "soldiers" fruticose "cups" squamulose base squamulose base xs X 1 Dinoflagellates: Pyrrophyta
Fossils of dinoflagellates extend back to the Ordovician killing mainly invertebrates, or not killing but concen• period of the Paleozoic era. Their relationship to other trating toxin in bivalve mollusks. The toxins produced algae is not known. Most are marine. by species of Gonyaulax are thousands of times more potent than cocaine, and may cause human death Characteristics. These microscopic organisms are uni• within 12 hours after consumption of affected bivalves, cellular and usually motile by means of a pair of but in low concentrations usually produce severe unequal flagella. There are diverse forms. Nutrition var• digestive upsets. ies from self-feeding (autotrophic) to mutually benefi• cial (mutualistic) to dependency upon a host (parasitic). Dinophyceae. This class of dinoflagellates is made up Pigments are chlorophylls a and c, carotene, and the of biflagellated motile cells. One flagellum is coiled xanthophyll, peridinin, which gives a gold-brown color around the transverse girdle groove (cingulum), pro• to the organisms. Starch is the stored food. The nucleus viding a rotating movement, and the other flagellum is is large and the chromosomes remain visible in all in a longitudinal groove (sulcus), functioning as a pro• stages (see 6), while the nuclear membrane remains pellant from the posterior end. intact. Some dinoflagellates have light-sensitive eye• spots. Some marine species are bioluminescent: when Gymnodinium cells are vigorously agitated, they give off flashes of light. The name means "naked whorl," as it is without armored plates. Structures shown are the girdle groove Reproduction. Asexually, reproduction is by cell divi• (a) with flagellum (b) and the sulcus groove (c) with fla• sion and cyst formation. Sexual reproduction is by sex gellum (d). Many chloroplasts (e) are visible. cells (gametes) that look alike (isogamy) or unlike (anisogamy). Ceralium
Of interest ... "blooms" or "red tides:" under optimal The name means "horned." Armored plates (f) orna• conditions fast reproduction produces heavy concen• mented with pits cover the organism. Structures are trations of dinoflagellates that color the ocean red, red• the girdle groove (g) with flagellum (h) and the sulcus brown, or yellow; toxins: these "blooms" can be toxic groove (i) with flagellum (j). to other organisms in different ways: killing only fish,
COLOR CODE
gold-brown: chloroplasts (e), plates (f)
55 Dinoflagellates
I~d \ Gymnodinium X 450
g
Ceratium X 450 Golden Algae, Yellow-green Algae, Diatoms: Chrysophyta
This diverse group of algae has common features, such into an oospore (m), which remains in the oogonium as as a sugar food reserve called chrysolaminaran (Ieu• a resting spore until germination. cosin); more carotene pigments than chlorophylls, thus the gold and yellow-green colors; and chlorophylls a Bacillariophyceae (Diatoms). Two hundred living gen• and c. The pigment, fucoxanthin, occurs in some of the era of unicellular diatoms are known. Diatom walls classes. Forms range from amoeboid cells, flagellated (frustules) have the structure of a narrow box with a cells, filaments, to parenchymatous thalloid types. lid. The lid, called the epivalve, fits over the box or hypovalve. The overlapping area is the girdle region. Chrysophyceae (Golden Algae). Members of this class Reproduction by cell division involves separation of the live mainly in fresh water. There are a few marine epivalve and hypovalve, with new, smaller container forms. Some have cell coverings which may contain sil• walls formed. When an ultimate, minimum size reduc• ica. Two-part resting spores (statospores) are formed tion is reached, new cells are formed by the fusion of when unfavorable conditions occur. Asexual reproduc• the protoplasm of two cells. Diatoms also have sexual tion is by fragmentation and an asexual reproductive reproduction. cell (zoospore). Sexual reproduction is not well-known. Of interest ... ecosystem: diatoms, the major com• Dinobryon ponent of plankton - base of aquatic food chains, are the single most important group of algae. In relation to This fresh water alga forms free-swimming colonies of other families, diatoms also supply the major percent• biflagellated cells. The protoplast (a) is connected by a age of the world's oxygen supply. They are affected by thin strand to its protective covering: a transparent, temperature, pollution, and light. Some characteristic open-ended, vase-shaped lorica (b). The protoplast has species of diatoms and other algae are indicators of 2 flagella (c) of unequal length, an eyes pot (d) and a polluted water, while other species are indicative of chloroplast (e). clean, non-polluted water. Fossils: diatomaceous earth is the silica remains of diatoms; it is used for filters, Xanthophyceae (Yellow-green Algae). Fresh water abrasives, insulation, in pavement paints, and as an habitats are typical for this class of algae. They form a indicator of oil- and gas-bearing formations. scum in standing water, and some occur on the surface of moist mud and on tree trunks. Pinnularia
Vaucheria The epivalve (n) portion fits over the hypovalve (0) in this diatom diagram. This alga is a branching filament (f) containing many chloroplasts (g). It may form mats under moist, green• Asterionella house, clay pots. The filament has no cross-walls except where reproductive chambers are formed. This diatom forms a star-shaped colony of cells (p). Reproduction is by asexual zoospores and by the sex• ual union of a small motile sperm with a large non• Coscinodiscus motile egg (oogamy). An antheridial branch (h) contain• ing sperm cells (i) forms laterally on a filament. A bifla• Surface striations (q) of puncture holes mark the wall gellated sperm cell swims to a pore (j) in the oogonium (r). (k) to fertilize the egg (I). The fertilized egg develops
COLOR CODE
red: eyespot (d) yellow: protoplast (a), diatoms (n, 0, p, q, r) yellow-brown: chloroplast (e) yellow-green: filament (f), oospore (m) tan: sperm cells (i), egg (I)
56 Dinobryon colony of cells X 450
j Golden Algae \
Sexual Structures X 450 Vaucheria
Yellow-green Algae
Filament X 40
a n
Diatoms
Asterionella Pinnularia colony of cells Coscinodiscus diagram X450 X 150 Red Algae: Rhodophyta
Red algae, with about 400 genera, are mostly marine ing in water-base paints and as a flexible starch in laun• plants with only a few known freshwater genera. Most dering); agar: Celidium (agar, used as a culture medium are found in tropical areas where they occur at great in microbiology, as non-irritant bulk in human intestinal depths or along intertidal regions. disorders and to make pill capsules); coral reefs: Cor• al/ina, Lithothamnium, and Calaxaura accumulate cal• Characteristics. Color varies greatly depending on the cium carbonate, which contributes to reef building; amount of pigments and can range from shades of ecosystem: red algae provide food for marine animals; green, red-brown, bright red, blue, and purple-blue to food: Chrondrus crispus (Irish moss), Porphyra (nori), black. Usually, the green pigments, chlorophylls a and Palmaria (dulse). d, are masked by the phycobilin pigments (red phy• coerythrin and blue phycocyanin). Other pigments are Porphyra Nori carotenes and xanthophylls (see 4). Red algae are rel• atively simple vegetative plants with complex repro• This genus, in the subclass Bangiophycidae, has a leafy ductive systems. The primary food reserve is floridean thallus (a) with rhizoidal cells at the base for attachment starch (a polysaccharide = carbohydrate made up of to rocks. many glucose units). There are a few microscopic uni• cellular forms, but most are branched filaments or flat Polysiphonia leaf-like forms. Placed in the subclass Florideophycidae, this genus has Reproduction. Asexual reproduction is by fragmenta• a filamentous thallus (b) constructed of many (poly) tion and vegetative spores. Red algae are divided into tubes (siphons, c); hence its name. Male gametophyte two subclasses. In the more primitive Bangiophycidae, plants produce special branchlets, trichoblasts (d), sexual reproduction is mostly absent. In the more bearing spermatia (e). Female gametophyte plants pro• advanced Florideophycidae, sexual reproduction is duce urn-shaped structures, cystocarps (f), which con• oogamous: non-flagellated male gametes (spermatia) tain egg cases (carpogonia). After fertilization and mat• are carried by water to a stationary female gamete• uration, carpospores (g) are released. Carpospores bearing structure called the carpogonium. develop into a tetrasporophyte generation, producing tetras pores which germinate into male or female game• Of interest ... colloids: Chondrus crispus (carra• tophytes (gamete-bearing plants). Both the tetraspo• geenan, used as a stabilizing agent in milk products, jel• rophyte and gametophyte generations have the same lied foods, cosmetics, insect sprays, and water-base external filamentous appearance. paints), Cloiopeltis (funori, used as a water-soluble siz-
COLOR CODE
red-purple: thallus (a) red: thallus (b), tubes (c), trichoblast (d, e), cystocarp (f), carpospores (g)
57 Red Algae
a
Porphyra habit X¥"
Habit X 1
Polysiphonia
g
c
Trichoblast vertical section Cystocarp on male gametophyte on female gametophyte X 450 X 200 Green Algae: Chlorophyta
Green algae constitute a very ancient group of plants fixed number of cells). A gelatinous sheath (f) surrounds with fossils occurring back to early periods of the the flagellated (g) cells. The chloroplast (h) contains an Paleozoic era. They are mainly freshwater plants, but eyespot (i). also occur in saltwater, in soil, on tree bark, and on snow. Cladophora
Characteristics. Green algae forms are unicellular, This alga has a branched filament whose cells contain colonial, filamentous, membranous (resembling leaves), pyrenoids (j) in reticulate chloroplasts (k). and tubular. The cells have many of the organelles found in cells of higher plants, such as a rigid cell wall; Acetabularia a nucleus with one or more nucleoli; a large vacuole; well-organized chloroplasts; pigments of chlorophylls a This marine alga, known as "mermaid's wineglass," is and b, carotenes, and xanthophylls; self-feeding nutri• one immense cell with a giant nucleus (I) in the basal tion (autotrophic); and pyrenoids associated with rhizoid (m). The nucleus migrates to the cap (n) where starch formation. Motile forms usually have two whip• reproductive cysts are formed. lash flagella of equal length. There are many varying types of asexual and sexual reproduction. Scenedesmus
Of interest ... phylogeny: green algae are considered This is a coenobium of four cells joined laterally. The to be on the direct evolutionary line to higher vascular laminate chloroplast (0) contains a pyrenoid (p). There plants; ecosystem: they contribute to the freshwater is one nucleus (q) per cell. plankton of the food chain. Micrasterias Note: Of 450 genera, the few illustrated here are microscopic, with the exception of Acetabularia. The cell wall, enclosed by a gelatinous sheath (r), is divided into two halves. Each half has a chloroplast (s) Chlamydomonas with pyrenoids (t). The nucleus is located at the con• traction (isthmus, u) between the cell halves. This unicellular alga is motile by means of two flagella (a). The cup-shape chloroplast (b) containing a red Spirogyra eyespot (c) and a pyrenoid (d) surrounds the nucleus (e). One cell of this filamentous alga is shown. It has two spiral chloroplasts (v) with numerous pyrenoids (w). Eudorina The nucleus (x) is suspended in the center by threads of cytoplasm. Sixteen cells make up this coenobium (a colony of a
COLOR CODE
colorless: flagellum (a, g), sheath (f, r), rhizoid (m) white: pyrenoid (d, j, p, t, w) gray: nucleus (e, \, q, u, x) red: eyespot (c, e, i) green: chloroplast (b, h, k, 0, s, v), cap (n) 58 Green Algae
Eudorina (colonial)
Chlamydomonas (unicellular)
n
Scenedesmus (colonial) Cladophora (filamentous)
Acetabularia (unicellular) X 1M?
v
s
Micrasterias Spirogyra (unicellular) (filamentous) Brown Algae: Phaeophyta
The algae in this division are mainly marine. They live Ectocarpales. Of the 13 orders, the most primitive along cooler coastal, intertidal areas. Common features brown algae are found in this order. The plant body among the different genera are the pigments of chlo• (thallus) consists of erect filaments of a single row of rophylls a and c, i3-carotene, violaxanthin and fuco• cells (uniseriate) with basal branching systems (hetero• xanthin; a sugar food reserve; laminarin; and cell walls trichy). Their size ranges from microscopic to forms up made up of an inner cellulose layer and an outer muci• to 25 cm long. laginous layer. Diverse size ranges from microscopic to enormous kelps up to 60 meters in length. Asexual fctocarpus reproduction is by fragmentation and sporangia with zoospores. Sexual reproduction is by sex cells This alga is found on most seashores growing upon (gametes) that look alike (isogamy) or are unlike other plants (epiphytic). The filaments (a, b) of this plant (anisogamy), or a motile sperm with a stationary egg have a filmy appearance. The cells have net-like (re• (oogamy). ticulate) chloroplasts (c). Alternate generations are spo• rophyte plants and male and female gametophyte Of interest . . . ecosystem: dense beds of kelp along plants. The sporophyte produces two types of repro• sea coasts provide a substrate for small animals, pro• ductive structures. A multicellular (plurilocular) sporan• tection and food for swimming animals and fish, and gium (d) produces 2n zoospores, which germinate into contribute to phytoplankton communities; industry: another sporophyte plant. A unicellular (unilocular) algin (a cell wall constituent) contains sodium, ammo• sporangium (e) produces 1n zoospores which germi• nium, and potassium salts (these salt compounds are nate into gametophyte plants. Gametophyte plants used in fireproofing fabrics, as laundry starch substi• develop plurilocular gametangia (f) producing motile tutes, as ice cream stabilizers, as binders in printer's ink, gametes of the sex of the parent plant. Fusion of male in soaps and shampoos, in photographic film coatings, and female gametes results in a 2n (diploid) sporophyte in paints and varnishes, and in leather finishes, insecti• plant. If a gamete does not fuse with another gamete, cides, toothpaste, shaving cream, and lipstick); fertil• it may by parthenogenic germination produce a 1n izer: brown algal plants contain more potassium, less (haploid) sporophyte. There are also other more com• phosphorus, and about the same proportion of nitro• plicated variations in the life cycle of Ectocarpu5. gen as animal manure; food: species of kelps are used as food (lombu) in Japan.
COLOR CODE
tan-green: sporophyte (a), filament (b), chloroplasts (c) tan: sporangium (d, e), gametangium (f)
59 Brown Algae
a
d
Sporophyte b habit X 1
onPleuilocular sp Sporangium orophyte X 450
Ectocarpus e
Unilocular Sporang" Pleurilocular G on sporo h lum on gameto h ametangium X 450 P yte X 450 P yte Brown Algae (continued)
Laminariales (Kelps). This order consists of the kelps, the largest of all algal plants. The microscopic gameto• phytes have male and female gametes on separate plants (dioecious). The characteristic tissue of the spo• rophyte is composed of randomly arranged cells (parenchyma), for photosynthesis and storage, rather than a continuous filament of cells. Well-developed meristems generate new cells which contribute to growth in length and width. The macroscopic sporo• phyte structure consists of a blade, stalk (stipe), and holdfast part that is attached to the rocky substrate.
Laminaria
Most species in this genus have perennial basal struc• tures consisting of a stipe (a) and a root-like holdfast (b). There is a loss, but replacement of the sporophyte blade (c) by the stipe's meristematic region. The repro• ductive structures of the sporophyte are asexual uni• locular sporangia (d) containing zoospores (e). Between the sporangia are paraphyses (f) with distended tips which provide protection for the zoospores.
Nereocystis leutkeana Ribbon Kelp
This annual plant has blades that develop in the same manner as in Laminaria. Due to progressive splitting, the blades (g) appear ribbon-like. The top of the stipe (h) bloats into a gas-filled pneumatocyst (i), which serves as a float to maintain the blades at the water's surface as the stipe elongates. Sexual reproduction is oogamous as follows: the microscopic male gameto• phyte produces clusters of antheridia (k) containing biflagellated sperm at filament tips. The microscopic female gametophyte produces a non-motile egg in the oogonium (I). After fertilization, a zygote is formed which emerges from the oogonium and begins sporo• phyte development (m).
COLOR CODE
tan-green: stipe (a), blade (c) tan: holdfast (b), sporangium (d), zoospores (e), antheridium (k) white: paraphysis (f) yellow-brown: blade (g), stipe (h), pneumatocyst (i), sporophyte (m) brown: hold fast (j) transparent: empty oogonium (I)
60 Brown Algae
Sporophytes XJ5
g e
d
Sporangia X 450 h
Laminaria
Sporophyte Female Gametophyte X~ X 450
Male Gametophyte Nerocystis luetkeana X 450 Ribbon Kelp Brown Algae (continued)
Fucales. The algae in this order are unique in that the gametophyte generation has been suppressed. Thus, there is only a 2n (diploid) plant. It has oogamous sexual reproduction by 1n (haploid) gametes (see below), which arise by meiosis (see 30).
Fucus vesiculosus
The thallus consists of a holdfast, stipe (a), and flat, bilaterally branched blades (b) with midrib (c) and paired air bladders (pneumatocysts, d). The separate male and female plants have swollen fertile areas on the blade tips called receptacles (e). They produce either male or female conceptacles (f). A conceptacle has a pore (g) that opens from the surface of the recep• tacle to surrounding water. Also present in the concep• tacle are sterile, hair-like threads called paraphyses (h), and either oogonia (i) that produce eggs or antheridia (j) that produce biflagellated sperm. When eggs are released from an oogonium into the water, they pro• duce fucoserraten, a sex attractant, which causes the sperm to swarm around them. Fertilized eggs develop into 2n (diploid) plants.
COLOR CODE
brown-red: stipe (a), blade (b, c) tan: air bladders (d) brown: receptacle (e), oogonium (i), antheridium (j) colorless: conceptacle wall (f), paraphysis (h)
61 Brown Algae
c
e
(:\-----+-c
t\\: Receptacle b with conceptacles !;: X2 ______Jh ____ _
Fucus vesiculosus Rock Weed Kelp h Habit XM>
Conceptacle Conceptacle e vertical section vertical section female male X 120 X 120 Stoneworts: Charophyta
According to the fossil record, this ancient group of 6 living genera is developmentally between the green algae and the bryophytes. Stone worts grow sub• merged in fresh water with rhizoidal attachment to the substrata of either soil or rock. Encrustrations of cal• cium carbonate account for the "stonewort" name. An obnoxious odor is characteristic. Their pigments are chlorophylls a and b, carotenes, and xanthophylls. Sex• ual reproduction is oogamous, which means a motile sperm unites with a larger stationary egg.
Chara Stonewort
The base of the plant, the protonema (a) has rhizoids (b) while the upper portion has whorls of branchlets (d) at the nodes. The reproductive structures, male glob• ules and female nucules (e), arise at nodes on the branchlets.
The male globule (antheridium) has an outer layer of sterile shield cells (f). Small cells (g) arise on the inner surface which produce antheridial filaments (h). Each cell in the filament produces a single sperm with 2 strands (flagella) for motility. The shield cells break open, permitting sperm cells to swim free. The female nucule (oogonium) is attached by a short stalk-like cell (i). Sterile sheath cells (j) spiral around the single egg (k). At the top are small coronal cells (I). At maturity, slits that form under the coronal cells allow the sperm to enter the oogonium. After fertilization, the sheath cells thicken around the zygote (oospore), which overwin• ters. At germination in the spring, the zygote wall splits and the primary protonema (m) emerges.
COLOR CODE
gray-green: protonema (a, m), stem internode (c), branchlets (d) white: rhizoid (b) tan: nucules (e), sheath cells (j), egg (k), coronal cells (I) colorless: shield cells (f), filaments (h) red-brown: cells (g) green: stalk cell (i) 62 crushed to show antheridial filaments X 116 Chara Stonewort
c Germinating Embryo Nucule X 54 X 54 Liverworts, Hornworts, Mosses: Bryophyta
This most primitive group of green land plants consists a thread-like structure with rhizoids, then into a leafy mainly of perennials. The plants are small in size due to gametophyte. The young sporophyte is green and an inefficient conductive system, lacking vascular tis• photosynthetic. Its firm tissue eventually turns brown sue. Humid habitats provide a water medium for the and may persist on the gametophyte for years. Unlike motile (flagellated) sperm to reach the egg. Bryophytes the liverworts and hornworts, mosses show a great cannot tolerate salt water or excessive heat, dryness, deal of variation in gametophytes and sporophytes. freezing, or pollution. Mosses form large colonies by fragmentation and gemmae. Bryophytes have two generations. The dominant plant, Sphagnum centrale the gametophyte generation, develops from a 1n (hap• loid) spore and produces sperms and eggs. A fertilized The peat mosses (Sphagnum, i) grow in acid bogs. They egg forms a 2n zygote, which develops into the spo• secrete hydrogen ions, contributing to the acidity. This rophyte. By meiosis, the sporophyte produces 1n acid environment delays the vegetation decay process. spores that are dispersed and develop into gameto• Thus, sphagnum mosses contribute to mat formation at phyte plants. In some bryophytes, asexual structures the open water margin of the bog. This provides a hab• called gemmae cups (a) contain gemmae (b) that itat for other types of plants. Undisturbed, a bog can develop into gametophytes. eventually develop into a forest through the process of succession. Due to its great water-holding capacity, Hepaticae (Liverworts). The liverworts- are primitive Sphagnum peat derived from old bogs is added to gar• bryophytes. The gametophyte is flat and strap-shaped den soil to acidify it and hold moisture. as in Marchantia or leafy as in Bazzania. The gameto• phyte body (thallus, c) branches equally Andreaea rupestris (dichotomously). This plant is found mainly on rocky outcroppings. The leafy gametophyte (j) is branched. The sporophyte is Marchantia polymorpha raised on a stalk (pseudopodium, k). When the capsule (I) dries the inner walls contract into 4 slits, releasing the This species has unisexual thalli (dioecious). The male spores. gametophyte develops antheridia-bearing stalks (antheridophores, d), which produce motile sperm in Tetraphis pellucida its disc-shaped top. The female gametophyte develops an archegoniphore (e), which produces archegonia, Moist rotting logs in coniferous forests provide the flask-shaped structures containing eggs, under its main habitat for this plant. Leafy gametophytes (m), umbrella-shaped top. After fertilization, a 2n zygote attached by rhizoids (n), produce gemmae cups (0). develops into a sporophyte, which, in turn, produces The sporophyte is borne on a long stalk (seta, p), which spores that develop into gametophytes. twists near the capsule (q). A pleated covering (calyp• tra, r) protects the capsule; it falls off at maturity. A lid Anthocerotae (Hornworts). (operculum) opens to expose 4 teeth (peristome, s). Spores are released by wind or animals shaking the Anthoceros punctata capsule.
The gametophyte thallus (f) forms a flat rosette. Male C:OLOR CODE and female structures occur in the upper layers of the green: gemma cup (a, 0), gemmae (b), thallus (c, f, j, thallus. The union of sperm and egg produces the spo• m) rophyte. A foot (g) secures the sporophyte (h), to the tan: antheridiophore (d), archegoniophore (e), foot gametophyte thallus. The sporophyte splits at the top (g), pseudopodium (k), capsule (I, q), seta (p), into 2 valves to expose the spores. calyptra (r), teeth (s) black: sporophyte (h) Musci (Mosses). All moss gametophytes have 3 to 5 gray-green: thallus (i) ranked leaves. Most mosses develop from a spore into white: rhizoids (n) 63 Liverworts, Hornworts & Mosses
c d
Gametophyte with gemmae e X 2l!!
Marchantia polymorpha Common liverwort
Male Gametophyte X 2l!!
o Female Gametophyte X 2l!! s
m q
Anthoceros punctata Common Hornwort n p gametophyte at base sporophytes above X3 Gametophyte with gemmae X6 Sphagnum centrale Peat Moss gametophyte X 1J1J
Gametophyte with stalked sporophytes X6
Andreaea rupestris Moss Tetraphis pellucida gametophyte Four-tooth Moss sporophytes at top xn \Vhisk Ferns: Psilophyta
The whisk ferns are believed to be among the most ancient of living vascular plants. There is no known fos• sil record to determine relationships with extinct forms. There are two genera: Psi/a tum and Tmesipteris.
Characteristics. These are rootless, simple plants with rhizoids as anchoring structures and hairless (glabrous) upright stems with simple sterile appendages (ena• tions). The large spare cases (sporangia) are fused into two's or three's.
Reproduction. In whisk ferns an alternation of gener• ations results in a dominant sporophyte plant produc• ing alike spores (homosporous), which germinate into 1n (haploid) gametophytes. The underground game• tophyte, which forms mycorrhizal associations with fungi for nutrition, develops archegonia, each with 1 egg, and antheridia with flagellated sperm. After fertil• ization, a 2n (diploid) zygote forms, which eventually develops into a sporophyte plant. Asexual reproduc• tive bodies (gemmae) may be produced on the sporophyte.
Psilolum nudum Whisk Fern
This plant may be terrestrial or grow upon other plants (epiphytic) in the tropics and subtropics. The shoot is upright with dichotomously branching stems (a). Simple leaf-like appendages (b) emerge from the stem. The three-lobed spore case (c) has a small, forked, leaf-like scale (d) below.
Tmesipleris tannensis var. lanceolala
This plant is found only in the south-western Pacific Ocean area. It has a simple stem (e) with flat, single• veined, leaf-like appendages (f). The sporangium (g) is two-lobed.
COLOR CODE
light green: stem (a), appendages (b), scale (d) yellow: sporangium (c) green: stem (e), appendages (f) tan: sporangium (g) 64 Whisk Ferns
b
a
Psilotum sporangia Psilotum X 10 habit X 1
Tmesipteris sporangia X2 Tmesipteris habit X 1 Clubmosses, Spikemosses, Quillworts: l ycopodiophyta
This distinct group of ancient plants has five living gen• Selaginella rupestris Rock Spikemoss era. Common features are single-veined leafy appen• dages (microphylls), two-part branching which may be The creeping stem has spirally arranged leaves (d), rhi• equal or unequal, axillary sporecases (sporangia), and zophores (e), and 4-sided fertile spikes (f). flagellated sperm. Isoetales (Quillworts). These plants are considered by Lycopodiales (Club mosses). Lycopodium, with 400 some to be the last remnant of the fossil tree lycopods species, is found worldwide, with most species in the due to their peculiar secondary growth, heterospory tropics. Plants are herbaceous, perennial, and usually and presence of ligules. Isoetes, with 60 species, grows evergreen. No leaf outgrowths (Iigules) are present. mostly submerged in lakes, ponds, and streams. Some species bear sporangia in terminal spikes (strobili). Isoetes echinospora Braun's Quillwort
Lycopodium annotinum Stiff Clubmoss The sporophyte has an enlarged perennial under• ground stem, the corm (g). The roots (h) branch dichot• A creeping horizontal stem (rhizome) has upright omously, and annual strap-shaped leaves (i) grow in a shoots with annual constrictions (a). The spirally spiral cluster (rosette). The leaf has a ligule (j), 4 vertical arranged leaves (b) are narrow and spread in different air chambers (k), and an expanded fertile base covered directions. In the alternation of generations, the spore by a flap (velum, I). At the bases heterosporous leaves germinates into a plant (gametophyte) bearing male (mega- and microsporophylls) bear megasporangia (m) and female sex cells (gametes). After fertilization, an containing large spores (megaspores, n) or microspor• embryo develops into a sporophyte, the dominant angia (0) with small spores (microspores). The mega• plant. A "cone" (strobilus, c) of specialized leaves (spo• spore wall is ornamented variously according to rophylls), bearing sporangia in the axils, terminates an species. The megaspores develop into female game• upright shoot. The sporangia contain one type of spore tophytes, while the microspores produce male (homosporous). gametophytes.
Selaginellales (Spike mosses). Selaginella, the single Stylites andicola genus, has about 600 species. Differing from Lycopo• dium, there are ligules, root-like organs (rhizophores) This plant, forming cushions in marshes, was discov• occurring at dichotomies, and sporangia always in a ered in the Andes Mountains of Peru in 1957. The stem "cone," bearing spores of two sizes (heterosporous). (p) branches dichotomously with the leaves (q) atop Reproduction is the same as shown below in Isoetes. each section. The roots (r) develop on the sides of the stem.
COLOR CODE
dark green: leaves (b) green: spike (c), leaves (d, q), ligule (j) white: rhizophores (e), roots (h, r), megasporangium (m), microsporangium (0) tan: velum (I), stem (p) light green: spike (f), leaves (i) brown: corm (g) yellow: megaspore (n)
65 Clubmosses, Spikemosses & Quillworts Stylites andicola Quillwort
SeJaginel/a rupestris Rock Spike moss
lycopodium annotinum "'''M~-d Stiff C1ubmoss
d
Sporophyte X 2~
Sporophyte X 1 o
Microsporophyll side view X3 m
Megasporophyll X3
Isoetes echinospora n Braun's Quillwort Megaspore X 26 Horsetails and Scouring Rushes: Equisetophyta
The single genus, Equisetum, with 15 species, is the fquisetum variegatum Variegated Scouring Rush only present-day member of plants in this division. It is related to the fossil plant Calamites. Species of Equise• Equisetum stems (a) are grooved and possess hollow tum are found worldwide except in Australia and New air channels within. The air channels include a central Zealand. canal (b), carinal canals (c), and vallecular canals (d) at the bottom of each groove. Size and shape of the air Characteristics. These plants are less than 1 m in canals vary with species. height, with the exception of the tropical E. giganteum, which grows to 8 m in height. The plant consists of a fquisetum arvense Field Horsetail jointed underground perennial rhizome and annual upright jointed shoots. Species with branched shoots This species has two forms (dimorphic). In the spring, are commonly called "horsetails" and unbranched spe• an unbranched fertile shoot (e) emerges from the rhi• cies are known as "scouring rushes" because of their zome (f). It is short-lived and dies back when the spores earlier use as pot scrubbers (effective because of the are shed from the strobilus (g). The other form of stem presence of silica in the stem surface). The photosyn• (h) is smooth and branched (i). By summer, the thetic stem is round and grooved on the outside and branches have elongated. The leaf sheaths (j) in this hollow in the center. At the stem node is a sheath of species have dark, lance-shaped teeth (k). greatly reduced leaves of various teeth-like shapes, depending on the species. In branched species, whorls fquisetum /aevigatum Smooth Scouring Rush of branches develop at the base of the leaf sheath. Internodes of the rhizomes and aerial shoots elongate The scouring rush stem (I) is unbranched. The leaf by means of basally localized intercalary meristems (see sheath (m) is flared and has deciduous teeth (n). The 15). strobilus (0) shows the hexagonal surface of the spo• rophylls (p). Reproduction. The plant has an alternation of a spo• rophyte generation with an either male or bisexual fquisetum hyema/e Common Scouring Rush gametophyte generation as follows. The sporophyte produces a terminal "cone" (strobilus) with whorls of A sporophyll removed from the strobilus exposes the hexagonal scales (sporophylls) on stalks. Attached to sporangia (q) containing spores. each scale are 5 to 10 spore-bearing sacs (sporangia) containing alike spores (homosporous). The spores, fquisetum scirpoides Dwarf Scouring Rush which contain chlorophyll, germinate within a few days. They develop into tiny green thalloid gameto• A spore (r) surface splits into 4 strips of water-absorb• phytes which produce antheridia with sperm or both ing (hydroscopic) elators (s). When dry, the elators (t) antheridia and archegonia. Fertilization of the egg in an expand and aid in spore dispersal. archegonium by a sperm results in a zygote which develops into a new sporophyte plant.
COlOR CODE
green: stem (a, h), branches (i), sheath (j), sporangium (q) colorless: canals (b, c, d) tan: shoot (e), strobilus (g) dark brown: rhizome (f) yellow-green: stem (I), sheath (m), surface of sporophylls (p), spores (r), elators (s, t)
66 Horsetails & Scouring Rushes
,.. ""'''''''''''--- p
Equisetum variegatum Variegated Scouring Rush stem cross section X 34
m
Equisetum arvense Field Horsetail
m
Habit Equisetum laevigatum X S Smooth Scouring Rush
p
Equisetum hyemale Common Scouring Rush sporophyll q X 20
h h 5
r~ __
Equisetum scirpoides Dwarf Scouring Rush Spring Habit Summer Habit spores X~ X~ X 107 Adder's-tongue Ferns: Polypodiophyta
Polypodiophyta: Ferns Of interest ... ornamentals: Adiantum (maidenhair fern), Asplenium nidus (bird's-nest fern), Camptosorus Characteristics. Although fern origins are uncertain, (walking fern), Cibotium (tree fern), Cyrtomium (holly fossils have been found dating back to the Devonian fern), Nephrolepis (Boston fern), Onoclea (sensitive period. Most fern species have leafy fronds which fern), Osmunda (royal fern), Platycerium (staghorn unroll as the leaf expands (see 69). Stems lack second• fern); poisonous: Pteridium (bracken fern); horticul• ary growth, have roots, and are usually creeping or ture: Osmunda (dried roots used as medium for grow• below ground and may have protective hairs or scales. ing orchids); fertilizer: Azolla (mosquito fern, see 70). The leaves may be simple, feather-like (pinnate), lobed, with veins arising from one point (palmate), or with Ophioglossales (Adder's-tongue Ferns). Plants in this veins which appear to branch. Plant size ranges from a order are mostly small and succulent with the leaf few mm to 15 m. Ferns are perennials and may take divided into sterile and fertile, sporangial-bearing parts. the form of twining vines, floating plants, trees, epi• There are 3 genera. phytes, or, most commonly, terrestrial herbs. While most species of ferns are found in the moist tropics, Botrychium dissectum Dissected Grape Fern some grow in bare rocky habitats, or temperate swamps, fields and forests. The succulent compound leaf (a) is divided into pinnae (b) and pinnules (c). The fertile stalk (d) is divided into Reproduction. Asexual reproduction is by offshoots many branches where sporangia (e) are borne. The from a rhizome and by spores. The sporophyte gen• roots (f) are coarse. eration is dominant and produces 1n spores in spore cases (sporangia), usually on the lower leaf surface. The Helminthostachys zeylanica spore cases are massive in the primitive orders, Ophioglossales and Marattiales. In the more advanced This fern is found in southeast Asian and Polynesian orders, the spore cases are minute, nearly microscopic, swamps. The compound leaf is divided into 3 leaflets stalked, and in a "fruit dot" cluster called a sorus. The (h). The fertile spike (i) has very short branches bearing sculptured, thick-walled spores, dispersed by wind, sporangia (j). germinate into the sexual gametophyte generation. The tiny, rarely-seen gametophyte produces sperm in Ophioglossum vulgatum Adder's-tongue Fern antheridia and eggs in archegonia. For fertilization to take place, the sperm must swim in water to the arche• The single stalk (k) has one simple blade (I) without a gonium, a vase-shaped structure with one egg. After petiole (sessile), and sunken sporangia (m) borne ter• fertilization, a 2n zygote is formed and develops into a minally in a spike. The roots (n) are smooth and fleshy. sporophyte on the gametophyte. The gametophyte then dries up and dies.
COLOR CODE
green: leaf (a, b, c, h), stalk (d, g), spike (i) orange: sporangia (e, j) brown: roots (f) light green: stalk (k), leaf (I) yellow: sporangia (m) white: roots (n) 67 Adder's-tongue Ferns
m d
g
k
Helminthostachys habit XJIJ n
Botrychium Ophiog/~sum habit habit X 1 X)f Common Ferns: Polypodiophyta
Polypodiales (Common Ferns). Most common ferns are in this order. They are usually of medium size among the ferns and are found on most parts of the earth. Sporangia are single or more often there are many in a cluster called a sorus. In some genera, the sorus has a protective covering (indusium). Some ferns in this or'der produce sporangia on separate, fertile stalks, but most have the sporangia on the back of the frond (leaf) in sari, or on the entire surface, or in rows along the veins, or under the curled edge of the leaf• lets. There are over 8,000 species.
Osmunda regalis Royal Fern
The deciduous leaves arise from a perennial rhizome with black wiry roots. The fern leaf stalk (a) is twice divided into pinnae (b) and bears sporangial branches (c) terminally. The round, single spore cases (sporangia, d) open in halves and are in clusters (e).
Dryopteris spinulosa Spinulose Woodfern
The usually evergreen leaf of this fern is thrice-cut, forming delicate pinnules (f) in the pinna (g). Scales (h) cover the petiole (i). Produced on the leaf underside are sari. The sorus (j) is covered by a kidney-shaped indusium (k) that protects the sporangia (I).
COLOR CODE
red-brown: stalk (a), sporangium (d, I), sporangial clusters (e) green: pinnae (b), pinnules (f) tan: scales (h), petiole (i), indusium (k)
68 Common Ferns
a
Dryopteris k leaf d X~ e
Osmunda Osmunda Dryopteris leaf cluster of sporangia pinnule X~ X 10 X 10 Fern Leaf Development: Polypodiophyta
Polypodiales (continued).
Rumohra adiantiformis Leather Fern
Sturdy fronds of this tropical fern are frequently used by florists. The young leaf meristem is protected by scales (a, b). As in other common ferns, the fiddlehead (crozier, c, d) expands by unrolling (circinate develop• ment). As the stalk (petiole) elongates, the blade midrib develops leaflets (pinnae, e). In this genus, the leaflets are further divided into smaller leaflet sections (pin• nules, f, g).
COLOR CODE
brown: scales (a, b) green: crozier (c, d) dark green: leaf (e, f, g) 69 Fern Leaf Development
Rumorha adiantiformis Leather Fern x%
g abc d e Water Ferns: Polypodiophyta
Marsileales (Water Ferns). Water ferns in this order usually have rooted rhizomes. The leaf may have 0, 2, or 4 leaflets on a long petiole. Spore-bearing recepta• cles (sporocarps) are formed along the petiole. A spo• rocarp develops both small microspores and larger megaspores (a heterosporous condition) on one plant (monoecious).
Marsilea quadrifolia Water Clover
This pond plant is rooted (a) in soil with leaves floating on or near the water surface. The creeping rhizome (b) develops new leaves (c), which have 2 pairs of oppo• site leaflets (d).
Salviniales (Floating Ferns). The floating ferns are Sal• vinia and Azolla. The plant consists of a branched stem and leaves. Sporocarps containing two types of spores (heterosporous) are borne on the leaves.
Salvinia Water Spangles
The leaves are in whorls of 3 with 2 keeled, green float• ing leaves (f) and a colorless, finely divided, submerged leaf (g). The upper surface of the floating leaves is cov• ered with rows of 4 rib-topped, transparent hairs (h). The hairs cause water droplets to maintain surface ten• sion and roll off the leaf surface. The submerged leaf filaments are covered with brown hairs, which function as roots for water and nutrient absorption. Sporocarps (i) are borne on the submerged leaf filaments.
Azolla Mosquito Fern
This fern has simple roots (j) that hang down in the water. The leaves are alternate on the stem (k) and two-lobed, having a green, fleshy lobe (I) above the water and a colorless flat lobe (m) on the water sur• face. Some Azalia species have a symbiotic relationship with a blue-green, Anabaena (see 44), which lives in cavities of the fern. Anabaena converts nitrogen from the air into a reduced form (ammonia - NH 3) that can be used by the fern and surrounding water plants such as rice. Because the presence of Azalia with Anabaena increases rice production, this tiny plant is probably the COLOR CODE economically most important fern. brown: roots (a), leaf hairs (g) white: rhizome (b), root 0), stem (k) green: leaf (e), leaflets (d), petioles (e) light green: leaf (f), leaf lobe (I) tan: sporocarps (i) 70 Water Ferns
m
m
Stem Portion side view X 15 Habit from above Azolla X 10 Mosquito Fern
c
Hairs Habit on leaf surface X~ X 10
Mars/Ie" a quadrifolia Leaves Salvinia Water Clover X2 Water Spangles Cycads: Cycadophyta
Fossil history of the cycads extends back 200 millior. years to the Mesozoic era. Cycads are now confined to the tropics and subtropics as living relics of once worldwide distribution. They are the most primitive seed plants living.
Characteristics. Cycads look like sturdy ferns or palm trees. They have thick upright stems with a primary thickening meristem and not much secondary growth. The leaves are large, compound fronds with leaflets. Leaflets are thick and tough, usually with equally branching (dichotomous) veins. Typically, cycads reach a maximum height of 2 to 3 m, but some species grow to 20 m high. Cycad plants are slow-growing and long• lived, some to as old as 1,000 years.
Reproduction. Unisexual cones (strobili) are borne on separate plants (dioecious). The male cone has spirally arranged cone scales (microsporophylls) with spore cases (sporangia) on the lower surface. The spore case contains microspores that develop into pollen grains that are dispersed to the female reproductive cones. There, the pollen grain develops mutiflagellated sperm. The cycads and Ginkgo are the only living seed plants having flagellated sperm. The female cone scales (megasporophylls) produce ovules in which eggs develop. After fertilization, brightly-colored, usually red, seeds are formed. Cycads, Ginkgo, conifers, and gnetes are referred to as gymnosperms, meaning "naked seed," because the seeds are borne in an exposed position on the sporophyll.
ZiJmiiJ iuriufSCeiJ
Leaflets (a) have dichotomous venation but do not have midribs. They leave prominent leaflet scars (b) when they are shed (abscise). The male cone (d) has stalked cone scales (e) with clusters of spore cases (f) on the under surfaces. The female cone scale (g) has a hexagonal surface (h) and below are 2 ovules (j) in which the eggs develop.
COLOR CODE Dioon edule green: leaflets (a, 0) The habit illustration of this cycad shows the prominent tan: leaf stalk (c), spore case (f), cone stalk (k), stem (I) covered with old leaf bases (m). A spiral of cone scale stalk (i) leaves (n) emerges at the apex. Leaflets (0) are arranged brown: cone (d), cone scale stalk, surface (e) in two rows. dark green: cone scale (g, h) white: ovules (j) red-brown: stem, leaf (I, m) 71 Cycads
Zamia furfurscea
Male Cone X%
c
Scale b Male Cone X 2)2 Leaflets Scale Female Cone X% X 2)2
Dio6n habit X r,o Ginkgo: Ginkgophyta
This division has only one living member. Fossil records show it probably originated in the Permian period about 250 million years ago. Members of the division were globally distributed, but became extinct except for a single species in southeastern China. Ginkgo is similar to cycads in reproductive structures and game• tophyte development, but the leaves are distinctively different. The stem, with extensive wood, small pith and cortex, and cell wall pitting, is similar to that of the conifers (see 15).
Ginkgo bi/oba Maidenhair Tree
This plant was cultivated for centuries in temple gar• dens of China and Japan. The Chinese name was mis• transliterated and should be Ginkyo.
Characteristics. A hardy tree growing to 30 m in height and over 1 m in diameter can live up to 1,000 years. After the first 10 to 20 years of vertical growth, laterally spreading branches develop. The common name is derived from a resemblance of the leaves to the leaf• lets of the maidenhair fern (Adiantum).
The leaf blades (a) are fan-shaped, lobed, and have dichotomous venation. The alternate leaves are mainly 2-lobed (biloba, b) on long shoots (c) and wavy-mar• gined on short spur shoots (d) where they appear as in a whorled arrangement. In autumn, the deciduous leaves fade to yellow and all are shed from a tree within a few hours.
Reproduction. Unisexual structures are borne on sep• arate trees (dioecious). The male structures are catkin• like strobili (e) of spore cases that develop in leafaxils. Two male spore cases (f) develop on a stalk (g). The female strobilus has 2 terminal, "naked" ovules (h) on a stalk (i) and, thus, Ginkgo is referred to as a gymno• sperm (= naked seed). In the spring, wind carries pol• len to an opening (micropyle) in the ovule. The seed (j) has a fleshy outer layer with the odor of rancid butter when mature. An embryo with two primary leaves (cotyledons) develops after the seed has been shed. COLOR CODE
yellow: long shoot leaf (b), male strobili (e), spore Of interest ... this "living fossil" may be the oldest sur• cases (f) viving seed plant. It is cultivated as an ornamental green: leaves (a), stalks (g, i) shade tree because of its resistance to pathogens and tan: long shoot (c) pollutants, and its drought and low-temperature brown: spur shoots (d) tolerance. light green: ovules (h) yellow-orange: seed (j)
72 Ginkgo biloba Maidenhair Tree h h
Shoot with seed Female Strobilus X 1 X2
c
Shoot with male strobili X 1
b
g
Male Spore Cases long Shoot leaf 2 views X 1 X8 Conifers: Pinophyta
Conifers have been present since the Carboniferous. "berry" flavoring), Pinus spp. (seeds of pinyon pines); Present-day conifers have fossil records dating back to ornamentals: Araucaria (Norfolk Island pine), Cupres• the Jurassic period of the Mesozoic era. sus (cypress), Juniperus spp. (juniper, red cedar), Larix (larch, tamarack), Picea (spruce), Taxus (yew), Thuja Characteristics. Almost all conifers are woody trees, (arborvitae, white cedar), Tsuga (hemlock); poisonous: having one central trunk from which branches extend. Taxus (yew: wood, bark, leaves, seeds). Most have narrow, evergreen leaves commonly called needles (see 21, 22). Conifers prefer cooler climates Picea glauca White Spruce forming climax forests at high altitudes, as well as in the temperate regions. Conifers are the tallest known As a member of the pine family (Pinaceae), this tree has trees, with giant sequoia (Sequoia dendron giganteum) needle-like, evergreen leaves (a). The male cone is and redwood (Sequoia sempervirens), which may composed of spirally arranged cone scales (b) with pol• reach 100 m and live thousands of years. There are len sacs on the sides. In the spring, after clouds of yel• seven families: Pine (Pinaceae), Araucaria (Araucari• low pollen (c) are dispersed, the cone disintegrates. aceae), Sequoia (Taxodiaceae), Cypress (Cupressa• The young female cone has woody, spirally arranged ceae), Podocarpus (Podocarpaceae), Plum-yew cone scales (d) with outer bracts (e), and on the inner (Cephalotaxaceae) and Yew (Taxaceae). surface of each scale, 2 ovules (f). At maturity, the cone (g) opens and winged seeds (h) are released. Reproduction. Conifers bear pollen sacs and ovules in separate structures (strobili) on the same plant (mon• Taxus Yew oecious). Wind currents carry pollen to female strobili, which are usually cones. This yew family (Taxaceae) shrub has flat, evergreen leaves (i) and bears male and female structures on sep• Of interest ... timber and paper pulp: Abies (fir), Cha• arate plants (dioecious). The female reproductive struc• maecyparis spp. (false-cypress), Picea spp. (spruces), ture has scales (j) at the base, and a band of tissue (k) Pinus spp. (pines), Pseudotsuga (Douglas fir), Sequoia that matures into a fleshy aril (I) that envelops the seed (redwood), Taxodium (bald cypress); naval stores (tur• (m). The red aril attracts birds, which separate it from pentine, wood oil, wood tars, rosin): Picea spp. the seed. (spruces), Pinus spp. (pines); food: Juniperus (juniper
COLOR CODE
green: leaves (a, i) red: cone scales (b), aril (I) yellow: pollen (c), scales (j) tan: cone scale (d), bract (e), ovule (f), seed (h) brown: cone (g) light green: tissue (k) brown-green: seed (m)
73 Conifers
b
Shoot Male Cone Scale cone, seeds X8 X 1
d
Picea g/auca White Spruce
Female Cone Scale X4
Aril, Seed X 1
Taxus Yew
Shoot Female Cone X 1 X 3 Gnetes: Gnetophyta
There are 3 genera in this division, Ephedra, Welwit• schia, and Gnetum. Pollen grains of Ephedra have been found from the Permian period. Origins and relation• ships of these plants with others is not known, although they are termed gymnosperms because they bear exposed ovules.
Ephedra
These plants grow in warm, dry temperate areas. Oppositely-branching stems (a) bear whorls of scale• like leaves (b) and male structures (strobili, c) at the nodes. Sporangia (d) are protected by bracts (e) and bracteoles (f). Stalked female structures (strobili, g) are borne at nodes and protected by bracts (h). Two seeds (i) develop after fertilization. An alkaloid, ephedrine, which occurs in these plants, is used to relieve hay fever and asthma symptoms.
Welwitschia mirabilis
This unusual plant, discovered in 1860, is native to a small area on the dry, southwest coast of Africa. Plants may live for over 2,000 years. Its woody stem (j) pro• trudes slightly out of the soil and has only 2 strap• shaped leaves (k) produced from long-lived strips (intercalary meristems, I). Unisexual cones, borne on stalks that arise from the meristemtic region (see 15), are produced on separate plants (dioecious). The male cone is composed of bracts (cone scales) with brac• teoles (m) covering a smaller strobilus on each. With the bracteoles removed, 6 spore cases (sporangia, n), with 3 lobes each, may be seen. They surround a cen• tral, sterile ovule (0). Pollen is formed in the sporangia. The 4-sided female cone has overlapping scales (p). An integument (q), consisting of an outer layer of cells that covers the ovule, protrudes from each scale.
Gnetum
A plant of the tropics, most species are vines with a few shrubs and trees. Opposite leaves (r) resemble those of dicot flowering plants. Unisexual strobili are COLOR CODE produced on the same plant (monoecious) or on sep• arate plants (dioecious). green: stems (a), leaves (b, r), strobilus (c, g), bracts (e, h), bracteoles (f) yellow: sporangia (d, n) tan: seeds (i), stem (j), bracteoles (m), ovule (0), scales (p) light green: meristem (I) gray-green: leaves (k)
74 Gnetes k
k E. helvetica male c strobilus X4
h
E. procera E. procera female strobilus habit X4 X%
Ephedra
Habit XY:J
Welwitschia n
p
q
m
Cnewm leaves Male Strobilus Male Cone Scale Female Cone X12 X 10 X 412 X% Flowering Plants: Magnoliophyta Classification
The dominant plants of the earth today are the flow• ally separate and the pollen grains possess three pores ering plants. While their fossil record dates from the (see 31). Cretaceous period, when they diversified rapidly, their Commelinidae (16 families). Plants in this subclass are ancestral origin is not known (see 41, 42). Sizes range mostly terrestrial. The flower carpels are usually joined from a 1-mm duckweed (Wolffia) to the 100-m Austra• and the seed usually has a starchy endosperm (see 40). lian gum tree (Eucalyptus). The sepals and petals are separate, or reduced to bris• tles or absent. Flowering plants are called angiosperms, plants that have seeds enclosed in a fruit that develops from an Zingiberidae (9 families). This subclass is separated ovary. The division, Magnoliophyta, is divided into 2 from Commelinidae by the presence of septal nectar• classes: Magnoliopsida, the dicots (embryos with 2 ies, and vessels (see 8) are found only in the roots. seed leaves - cotyledons), and Liliopsida, the mono• Arecidae (5 families). The flowers are usually small and cots (embryos with 1 seed leaf). In the Cronquist clas• numerous in a cluster, subtended by a bract (spathe), sification system, there are 354 families in the two and often aggregated into a fleshy spike (spadix). classes. Liliidae (17 families). Tepals (sepals and petals that look alike) and well-developed nectaries are usually present Dicot (Magnoliopsida) Subclasses in the flower. This subclass includes the most special• Magnoliidae (36 families). These flowering plants are ized monocot flowers. among the most primitive. Their flowers usually have Evolutionary Floral Trends an indefinite number of parts with many petals, many stamens, and many separate carpels. Pollen grains have Evolutionary changes from primitive to more advanced one pore (see 31). forms may include the following. Hamamelidae (23 families). The flowers are small, usu• Reduction, where flower structures are less in size, ally unisexual, and are adapted towards wind number, and kinds of parts. Petals are most frequently pollination. lost; stamens or carpels may be lost (bisexual to unisex• ual flowers, see 28), with, usually, sepals the last to be Caryophyllidae (14 families). This group alone has the lost because they protect the young flower. water-soluble betalain pigments (see 4) of betacyanins There may be fusion of parts, such as petals forming a (beet red-purple) and betaxanthins (yellow, orange, tube instead of being separate. orange-red). The flower ovary usually has free-central Instead of a superior position, the ovary is in an inferior to basal placentation (see 28) and the ovule integu• position (see 28). The lower, less-exposed position ments are twisted and bent. provides more protection of the ovules. The shift from Dilleniidae (69 families). The flower has many stamens, insect to wind pollination is regarded as an advanced which mature in a sequence from inside to the outside. evolutionary change. Parietal placentation of the ovules is common. A change from radial to bilateral symmetry is an adap• Rosidae (108 families). Structurally, this group has no tation for specific insect pollinators. In radial (actino• one common feature, but developmentally, the plants morphic) symmetry, similar parts are regularly arranged are between the primitive Magnoliidae and the around a central axis. With bilateral (zygomorphic) advanced Asteridae. symmetry, flowers can be divided into equal halves in one plane only. Some advanced flowers are irregular Asteridae (43 families). In 70% of these plants, the (asymmetrical), incapable of being divided into equal flower petals are fused, at least at the base, and the stamens arise from the petals. halves in any plane. False flowers (pseudanthia) are composed of a head Monocot (Liliopsida) Subclasses (capitulum) of small flowers that look like one flower. In the center of the head are fertile flowers surrounded Alismatidae (14 families). These pnmltlve monocots on the outside by petaloid structures or large-petalled are mostly aquatic plants. The flower carpels are usu- sterile flowers.
75 Classification of Flowering Plants
Magnoliidae Magnolia Family (Magnoliaceae) Magnolia many, separate parts bisexual superior ovaries insect pollinated radial symmetry woody plant X 1 e Asteridae Aster Family (Asteraceae) Hamamelidae Tagetes Mangold Birch Family (Betulaceae) few, fused parts Betula Birch unisexual, bisexual few, separate parts inferior ovary Arecidae unisexual insect pollinated Arum Family (Araceae) inferior ovary irregular flowers Anthurium Flamingo Flower wind pollinated clustered in false flower few, fused parts irregular flowers herbaceous plant bisexual clustered in catkins X 2 superior ovary v woody plant insect pollinated Xl!> radial symmetry spadix of flowers herbaceous plant Caryophyllidae XJ!:J Pink Family (Caryophyllaceae) Dianthus Pink some fused parts bisexual Liliidae superior ovary insect pollinated radial symmetry herbaceous plant X 1 inferior ovary insect pollinated bilateral symmetry Dilleniidae herbaceous plant Mustard Family (Brassicaceae) X~ Lobularia Alyssum y few, separate parts bisexual x z superior ovary insect pollinated radial symmetry COLOR CODE herbaceous plant X 6J.\, green: bract (a, h, r), leaf (e), female catkin (g), sepals (i, k, 0) white: perianth (b), spadix of flowers (u), male-female Rosidae column (w) Rose Family (Rosaceae) Malus Apple blue: stamens (c, m, q) some fused parts pink: pistils (d, n), petals (p, y), ovary (t), sepals (x) bisexual tan: male catkin (f) inferior ovary red: petals (j), bract (v) insect pollinated o purple: petals (I) radial symmetry orange: petal (s) woody plant dark pink: lip petal (z) X 1 Major Land Plant Communities of the World
Tundra (a). A wet, arctic grassland supports lichens, grasses, sedges, and dwarf woody plants.
Northern Conifer Forests (b). Low temperatures pre• vail for at least half the year. The plants are spruces, firs, and pines.
Temperate Deciduous and Rain Forests (c). In the tem• perate zone, deciduous plants have an even distribu• tion of 30 to 60 in. of rainfall annually and moderate seasonal temperatures. Rain forests of the subtropics with high moisture and even temperatures have broad• leaved evergreens.
Temperate Grassland (d). These areas have a low annual rainfall of 10 to 30 in., which effectively pre• vents forest formation.
Tropical Savanna (e). Warm regions with 40 to 60 in. of rainfall and with a prolonged dry season have drought- and fire-resistant grasses with scattered trees.
Desert (f). With less than 10 in. of annual rainfall in desert regions, plants include rain-season annuals, suc• culents, which store water, and shrubs, which can remain dormant for long periods.
Chaparral (g). A mild climate with abundant winter. rains and dry summers supports a community of trees or shrubs with thick evergreen leaves. Fire is an impor• tant maintenance factor.
Tropical Rain Forest (h). Equatorial lowlands with 80 to 90 in. of annual rainfall have broad-leaved evergreens, including trees, vines, and epiphytes.
Tropical Scrub (i) and Deciduous (j) Forests. These are areas without an even distribution of rainfall. They are COLOR CODE composed of thorn forests of distorted, small hard• wood trees. tan: tundra (a) dark green: northern conifer forests (b) red: Mountains (k). Many irregular bands of different types temperate deciduous and rain forest (c) yellow: grassland (d) of plant communities are present. light green: tropical savanna (e) orange: desert (f) pink: chaparral (g) purple: tropical rain forest (h) brown: tropical scrub forest (i) gray: tropical deciduous forest (j) blue: mountains (k)
76 Major Land Plant C ommunities
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