Nonvacular/vascular plants

·       Nonvascular plants

o   Dominant Gametophyte

§  Sporophyte is ephemeral (briefly green, depends on gametophyte for nutrition.

o   Simple Bodies: Small, live in moist environments.

§  Few cells thick. Most are photosynthetic.

§  Lacks seeds.

§  Lacks leaves, stems, roots

§  Lacks vascular tissue.

·       Moss Life Cycle

o   Spores turn into a germinating spore, which turns into a rhizoid.

o   Produces a hermaphroditic gametophyte.

§  Antheridium: produces sperm

§  Archegonium: eggs

o   Fertilizes (autonomously) to produce a sporophyte.

o   The sporophytes only function is to produce spores, so they don't live very long (use a sporangium).

o   Ex: Liverworts, mosses, hornworts.

·       Vascular plants

o   Tracheids: Long, hollow cells that die to make tubes for conducting water over long distances. Allows for great size and for structural support. Plants with these became much larger and more durable.

o   History of Vascular plants: Stem only, made of stem and sporangia. Produces dichotomous branching (fork in the road). No roots, rhizoids and a rhizome produce the underground portion to hold in place. No leaves, stems are photosynthetic.

§  Leaves have 2 origins. Flattened, sterile sporangia turned into leaves called microphylls. Or, side branches fused into a branching leaf called megaphylls (far more efficient).

o   Dominant Sporophyte: No obvious reason why, but only a correlation (most vascular plants have a longer sporophyte generation).

o   Innovations

§  True roots

§  Some reproduce using seeds

§  Seedless vascular plants have very primitive characteristics.

§  Such as dichotomous branching.

§  Lacking leaves (stems are photosynthetic).

·       Lycophytes: Simplest vascular plants. Also called "club mosses" but aren't mosses. Have microphylls with many microsporangium in them.

o   Dichotomous branching

o   No seeds, spores in sporangia.

o   Uncommon.

o   Primary material for peat and coal.

o   Ferns: No seeds.

o   Horsetails: Unbranched stem

o   Whisk Ferns: No leaves no roots, dichotomous branching.

·       Leptosporangiate Ferns (or just Ferns): Most diverse group. Gametophytes are very small, but both are green and photosynthetic.

o   Fern Life Cycle: Mature gametophytes are small, produces the gametes which fuse together to form the sporophyte embryo.

§  Sporophyte produces sporangium, which produces spores through meiosis.

§  The gametophyte has organs to produce the sporophyte (a standard fern). Dominant sporophyte. Ferns don't have flowers, they have leaves. Some leaves are photosynthetic, some produce sori (clusters of sporangia).

·       Seed Plants: Protect and nourish embryo during harsh conditions like winter. More than 80% of all biomass is a seed plant. Most successful thing on earth. Has two groups: gymno- and angiosperm

o   Gymnosperm: Produce seeds from cones

§  Cycads, gnetales, gingkos, conifers

o   Angiosperm: Have flowers, produce seeds in an ovary. Produce much diversity. Most successful, highly evolved. Male gametophyte produces pollen.