Vascular Plants Vascular Plants Tracheata n Nonseedbearing 4
Vascular Plants
Vascular Plants (Tracheata) n Non-seed-bearing (4 phyla) n n Seed-bearing (5 phyla) n n n All reproduce by means of spores rather than seeds “Naked” seeds (Gymnosperms; 4 phyla) Seeds enclosed in the fruits of flowers (Angiosperms) Contain lignified fluid-conducting vessels n Two kinds of vascular cells n n Xylem carries water and minerals from the roots to the rest of the plant Phloem transports photsynthate to other tissues
Seedless Vascular Plants
Differences between seedless vascular plants & bryophytes n Sporophytes are larger than gametophytes and are free-living n n Lignin production* True vascular system (Tracheophytes) Roots present Megaphylls*
Seedless Vascular Plants n n n The earliest seedless vascular plants lacked differentiation of tissues between root and shoot, and between stem and leaf. The evolution of these tissues enabled plants to reach great sizes. In all vascular plants, the sporophyte is the dominant life-cycle phase.
Vascular Plant Terminology #1 n Leaves- photosynthetic, principal lateral appendages of the stem. n n Microphylls- small leaves that contain a single strand of vascular tissue. Megaphylls- large leaves that contain multiple strands of vascular tissue.
Vascular Plant Terminology #2 n n Homosporousproduction of one type of spore from one kind of sporangium. Heterosporousproduction of two types of spores from two different kinds of sporangia.
Vascular Plant Terminology #3 n Sporophyll- a modified leaf that bears sporangia. n Sporangium- a structure that produces spores.
Vascular Plant Terminology #4 n Microsporophyll- a modified leaf that bears microsporangia. n n Microsporangia- a sporangium that produces microspores. Megasporophyll- a modified leaf that bears megasporangia. n Megasporangia- a sporangium that produces megaspores.
Vascular Plant Terminology #5 n Strobilus- a reproductive structure consisting of nonphotosynthetic sporophylls; a cone. n Microstrobilus- a microsporangiate cone. n Megastrobilus- a megasporangiate cone.
Homosporous vs. heterosporous n Majority of pteridophytes are homosporous n n Produce only 1 kind of spore during meiosis A few ferns and all seed plants are heterosporous n Produce micro/megaspores
Seedless Vascular Plants n Four Phyla n n Lycophyta (club mosses) Psilophyta (whisk ferns)
Seedless Vascular Plants continued… n Four Phyla n n Sphenophyta (horsetails) Filicinophyta (ferns).
Pteridophyta- ferns and fern allies n n n n Pteri- gr. wing or feather. Leaves- megaphylls Variable branching patterns. Sporangia in sori, lateral, or on sporangiophores in strobili. Heterosporous & homosporous. Distribution- global, tropics. Examples- Polypodium, Psilotum, Equisetum).
Psilotales- whisk ferns. n n n n n Psilos- gr. bare. Leaves- scale-like Eusporangiate Sporangia lateral Dichotomously branched. Homosporous No roots, stems Distribution- tropical & subtropical. Habitat- epiphytic or on rich soils.
Phylum Lycopodiophyta n Lycopodiaceae –the club mosses n n n Almost all living lycophytes belong to this family Are homosporous Young sporophyte remains attached for awhile, but eventually becomes free-living
Lycopodiophyta- lycophytes n n n n Lykos- gr. wolf, pous- gr. foot Microphylls present Plants + or - dichotomously branched Sporangia on or in the axils of sporophylls on strobili Heterosporous & homosporous Distribution- global Habitat- forest floors, deserts, aquatic Examples- Lycopodium, Selaginella, Isoetes)
m Lycopodiophyta Lycopodium
Lycopodium
Phylum Pteridophyta Equisetum
Equisetales- horsetails n n n n n Equus- L. horse, saeta- L. bristle. Leaves- microphyll-like, scaly. Homosporous. Sporangia on sporangiophores in a strobilus. Whorled leaves, but not dichotomous. Roots and stems (ribbed and jointed). Distribution- global. Habitat- along streams in moist sites. ~15 species. Example- Equisetum.
Equisetum- Equisetales
Phylum Pteridophyta: Equisetum
Phylum Pteridophyta n n Equisetophytes -2 cd major evolutionary line of Pteridophytes Equisetum is the only living representative n n May be oldest surviving genus of plants Widespread in moist or damp places Have small scale-like leaves that are whorled at the nodes The internodes are ribbed n ribs are strengthened with siliceous deposits n n “scouring rushes” Homosporous
Phylum Pteridophyta n The ferns and “fern allies” n n Majority are ferns Equisetum now grouped w/ Pteridophyta 2 cd largest group of plants besides angiosperms Most found in the tropics
Phylum Pteridophyta n Order Filicales –most familiar ferns n n Homosporous ferns A few unique features of ferns are specialized characteristics as they occur no where else among the vascular plants*
Phylum Pteridophyta n n n Have rhizomes Only seedless vascular plants to possess welldeveloped megaphylls* The large fronds perform what function for the fern?
Phylum Pteridophyta Fiddleheads Sori on fronds
Phylum Pteridophyta
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