Bryophytes and Seedless Vascular Plants

Ploidy

The number of sets of chromosomes in an organism.

Diploid

Two sets of chromosomes, represented as 2n.

Haploid

One set of chromosomes, represented as n.

Gametophyte

The haploid form of an organism that produces male and female gametes.

Sporophyte

The diploid form of an organism that produces haploid spores.

Alternation of Generations

The life cycle process involving the alternation between sporophyte and gametophyte stages.

Meiosis

The process by which the sporophyte forms haploid spores.

Mitosis

The process by which haploid spores develop into gametophytes and then into gametes.

Fertilization

The process where gametes combine to form a diploid zygote.

Bryophytes

Non-vascular plants that include liverworts, mosses, and hornworts.

Hepatophyta

The phylum of liverworts.

Bryophyta

The phylum of true mosses.

Anthocerophyta

The phylum of hornworts.

Nonvascular Plants

Plants that lack specialized tissues for transporting water and nutrients.

Thallus

The body of a liverwort.

Rhizoids

Hairlike structures that anchor the thallus of liverworts.

Thalloid Liverworts

Liverworts with flat, leaflike lobed bodies.

Leafy Liverworts

Liverworts that resemble mosses.

Operculum

A lid-like structure on the tip of the moss capsule.

Peristome

Teeth-like structures that secure the operculum to the capsule in mosses.

Protonema

The immature stage of moss that develops into the leafy gametophyte.

Vascular Plants

Plants with tissues for conducting water and nutrients.

Xylem

Tissue that conducts water and dissolved minerals.

Phloem

Tissue that conducts nutrients and hormones.

Phylum Lycophyta

The phylum that includes club mosses, quillworts, and spike mosses.

Homosporous

Producing only one type of spore.

Rhizome

A structure that produces aerial stems and underground roots.

Strobilus

A cone-shaped structure that contains spores.

Phylum Psilotophyta

The phylum known as whisk ferns.

Phylum Sphenophyta

The phylum known as horsetails.

Microphylls

Small, scalelike leaves arranged in whorls at the nodes of horsetails.

Pith

The hollow center of the stem in horsetails.

Sporangiophores

Structures that make up the strobili and contain sporangia in horsetails.

Phylum Pterophyta

The phylum that includes ferns.

Fronds

The leaves of ferns that arise from rhizomes.

Fiddlehead

The immature, tightly rolled structure of fern fronds.

Pinnae

The leaflets of compound frond ferns.

Petiole

The stalk that attaches pinnae to the rhizome.

Sori

The sporangia of ferns, appearing as brown spots on fronds.

Indusium

A protective flap covering the sori in ferns.

Annulus

The fuzzy region of the sorus that helps release mature spores.