The 293,000 . made of eukaryotic cells; all plants are multicellular; most are large with distinct tissues (dermal, vascular & ground tissues) and organs; some of the major organs are roots, stems, , flowers and fruits; they are nonmotile, usually anchored in the ground but some attach to other plants; have fairly thick, rigid walls of cellulose giving most individual cells a square or rectangular shape; almost all are green; contain the pigment chlorophyll inside organelles called that carry out photosynthesis. Plants are classified into 4 major groups.

Mosses & Allies (~23,600 species) most ancient plants and simplest surviving plants, most are small, inconspicuous and live in moist habitats; generally poorly adapted to on land: no vascular tissue, no true organs; distinctive alternation of generations with asexual and sexual producing sperm and egg. ( Bryophyta) 16,000 species generally poorly adapted to land, live in dense beds on moist soil, rocks or bark; each individual has tiny rootlike rhizoids for attachment (not to absorb nutrients for the plant); slender stemlike structure bears leaflike blades; no vascular tissue, therefore no true roots stems or leaves; gametophyte is the dominant : Liverworts (Phylum Hepaticophyta) 9,000 species small inconspicuous plants; grow on moist soil, rocks, stumps and bark; especially common in coniferous forests; gametophyte body is flattened, branching thallus with umbrella shaped clusters of antheridia or archegonia; life cycle is similar to mosses (Phylum Anthocerotophyta) 100 species gametophyte superficially resembles liverwort thallus; found in “disturbed” habitats (eg. fallow fields, roadsides); after fertilization a spikelike “horn” grows out of thallus

Ferns & Allies (11,000 species) mostly terrestrial, a few are aquatic; in temperate regions they typically inhabit swamps and moist areas; have true vascular tissueshave true roots, stems and leaves; still require water for sexual reproduction; sporophyte and gametophyte are completely separate plants

Ferns (Phylum Pterophyta) 10,000 species mostly terrestrial, a few are aquatic; range from tropics to arctic but most are tropical ; spore production occurs on underside of in clusters of sporangia called sori spores germinate into a gametophyte called a prothallium Whisk Ferns (Phylum Psilotophyta) 12 species mainly tropical; simple dichotomously branching stems with underground rhizome; small scalelike leaves; distinctive sporangia producing spores which germinate into prothallium. Horsetails (Phylum Sphenophyta) 40 species today consists of a single ; grow mostly in wet marshy habitats; up to 4 feet tall; on every continent except Australia; hollow jointed stems are impregnated with silica giving stem a gritty texture (=scouring rushes); at each joint is whorl of small nonfunctional leaves (megaphylls) Club Mosses (Phylum Lycophyta) 501 species ancient group that once were the dominant forests on land; today, common in temperate forests; many are epiphytic; distinctive alternation of generations; some with two different kinds of spores

Conifers & Allies (760 species) have much more efficient vascular tissue than ferns can grow larger, taller; most are or shrubs with needle-like leaves; sexual reproduction only by male and female cones; male cone produces that is blown by wind to female cone; fertilized egg becomes a naked borne on the female cone (Phylum Coniferophyta) 590 species conifers group contains one of world’s most massive organisms & world’s tallest organism: Coastal Redwood; nearly all are perennial trees & shrubs; in most conifers, leaves are needle or scale; nearly all conifers are evergreen; many conifers produce ; no asexual reproductive organs; greatly reduced alternation of generationsSexual reproduction becomes the main means of reproduction; sexual reproductive organs are cones; male cones produce pollen; zygote develops into seed; the are exposed usually on a cone (Phylum Cycadophyta) 100 species cone bearing palmlike plants of tropics and subtropics; living from age of dinosaurs; similar to conifers but seed structure is more primitive Ginkgoes (Phylum Ginkgophyta) 1 species consists of a single species that was once thought to be extinct; today is widely cultivated; with distinctive fan shaped leaves; as seed matures on female tree the outer fleshy covering gives off a foul odor Gnetophytes (Phylum ) 70 species group of unusual, highly adapted plants in three genera; most efficient vascular tissue of the group; in some the cone clusters resemble flowers of flowering plants

Flowering Plants (235,000 species, 90% all plants) dominant plants in world today90% of all living plant species; highly adaptable vegetative organs; complex symbioses with fungi, and enhance survival and efficiency; much more efficient transport tissues; no asexual reproductive organs or spores produced; sexual reproductive is the flower; seeds protected within a fruit Monocots ( ) 65,000 species floral parts in 3’s; leaves are long tapered blades with veins; stems with scattered vascular bundles; seeds with 1 cotyledon Dicots (Class Dicotyledons) 165,000 species floral parts in 4’s and 5’s; leaves broad with netted veins; stems with vascular bundles in one large circle; seeds with 2 cotyledons