Seedless Vascular Plants (Pteridophytes) - Key Terms

Vocabulary flashcards covering seedless vascular plants, their major groups, structures, life cycles, and key terms.

Seedless vascular plants

Plants with vascular tissue but without seeds; reproduce by spores rather than seeds.

Pteridophytes

Group of seedless vascular plants including ferns, whisk ferns, and horsetails; vascular tissue present; sporophyte typically dominant.

Pterophyta

Phylum that includes ferns and whisk ferns; seedless vascular plants without seeds.

Lycophyta

Club mosses; seedless vascular plants with microphylls and sporangia on fertile leaves.

Equisetophyta

Horsetails; extant genus Equisetum; branched or unbranched stems; reduced leaves; strobili with sporangia.

Rhyniophyta

Early vascular plants with substantial fossil record and simple morphology; first with effective vascular tissue.

Cooksonia

Best-known genus from Rhyniophyta; early vascular plant fossil.

vascular tissue

Columns of elongated, specialized cells forming a network from roots to leaves for transport.

sporophyte

Diploid, spore-producing generation; in vascular plants, usually the dominant stage.

gametophyte

Haploid generation that produces gametes; often small or subterranean in seedless vascular plants.

dominant sporophyte generation

Sporophyte is larger and more persistent than the gametophyte in vascular plants.

xylem

Vascular tissue that transports water and minerals from roots to the rest of the plant.

phloem

Vascular tissue that transports sugars and hormones from source to sink.

cuticle

Waxy protective layer reducing water loss on the surfaces of plants.

stomata

Pores in leaf surfaces that regulate gas exchange and water loss.

megaphylls

Leaves with highly branched veins; larger and more complex leaves common in many ferns.

microphylls

Leaves with a single unbranched vein; associated with lycophytes; origin from outgrowths of the main stem axis.

planation

Evolutionary orientation of smaller stems into the same plane.

overtopping

Differential growth where some stems grow over others to create a canopy.

webbing

Parenchyma tissue filling gaps between stems, creating a web-like network.

rhizome

Horizontal underground stem from which leaves and roots develop.

frond

Fern leaf; often highly divided and maturing from a rhizome apical bud.

sori

Clusters of sporangia on the abaxial (underside) surface of a fern frond.

indusium

Protective covering over a sorus.

annulus

Ring of thick-walled cells in a sporangium that drives spore release.

sporangium

Capsule in which spores are produced by meiosis.

sorus

Cluster of sporangia on the underside of a leaf, often protected by an indusium.

sporophyll

Leaf bearing sporangia; can be part of a strobilus or fertile shoots.

sporangiophore

Stalk bearing a sporangium or group of sporangia.

synangium

A fused group of sporangia forming a single unit (seen in Psilotum).

heterospory

Production of two distinct spore sizes (microspores and megaspores) leading to separate male and female gametophytes.

homospory

Production of a single type of spore that typically forms a bisexual gametophyte.

microspore

Small spore that develops into a male gametophyte.

megaspore

Large spore that develops into a female gametophyte.

archegonium

Female gametangium that produces eggs.

antheridium

Male gametangium that produces sperm.

zygote

Diploid cell formed by fertilization; develops into the sporophyte.

embryo

Developing sporophyte within the female gametophyte after fertilization.

cone / strobilus

Cone-like reproductive structure bearing sporangia; in some seedless plants as a major reproductive unit.

strobilus

Cone-like arrangement of sporangia on sporophylls or fertile branches, common in Lycophyta and Equisetophyta.

Psilotum

Whisk fern; primitive seedless vascular plant with dichotomously branched stems and synangia; lacks true roots and leaves.

protostele

Stem vascular tissue arrangement where the solid core is a basic, central mass of xylem/phloem.

siphonostele

Stem arrangement with a hollow central canal surrounded by vascular tissue.

eustele

Leafy stem arrangement with discrete vascular bundles arranged in a ring or discrete bundles.

Lycopodium

Genus of Lycophyta (club mosses); microphylls and sporangia on sporophylls, often in strobili.

Selaginella

Genus of Lycophyta; heterosporous with micro- and macrospores; separate male and female gametophytes.