BSC226: Early Vascular Plants,Lycopods, and ferns

Primary growth

The growth that occurs close to the tips of roots and stems, initiated by apical meristems and involved in extending the plant body.

Secondary growth

Additional growth that thickens the stem and root caused by activity in lateral meristems.

Vascular tissue system

Conductive tissues such as xylem and phloem embedded in the ground tissue system.

Tracheary elements

Conducting cells of the xylem with distinctive lignified wall thickenings.

Tracheids

The only type of water conducting cells in most vascular plants, other than angiosperms and gnetophytes.

Vessel elements

Principal water-conducting cells in angiosperms, evolved independently in several groups of vascular plants due to convergent evolution.

Sieve elements

Conducting cells of the phloem with soft walls.

Protostelic

A simple primitive arrangement of conductive tissue in stems and roots, consisting of a solid cylinder of xylem surrounded by phloem.

Microphylls

Leaves with a small vascular bundle, consisting of a single strand of vascular tissues.

Homosporous

Producing only one kind of spore.

Heterosporous

Producing two types of spores and sporangia.

Ligule

A specialized basal cell, a scale-like outgrowth near the base of the upper surface of each microphyll and sporophyll (unknown usage).

Corm

A short compact underground stem.

CAM (Crassulacean Acid Metabolism) photosynthesis

A photosynthetic pathway where plants take up CO2 from substrates and join it with PEP to form acids.

Monopodial branching

A branching pattern where a single major axis is present, not dichotomously branched.

Sporangia

Structures that produce spores.

Strobili

Cones or compact groups of sporangia found on the stems. Found in Lycopodiophyta and Equiseophyta

Fronds

Leaves that consist of a divided blade and petiole.

Pinnae

Little leaflets that make up a compound leaf.

Sori

Compact groups of sporangia found on the underside of leaves.

Indusium

A protective covering of sori.

Prothallus

The gametophyte stage of ferns, containing archegonium and antheridia.

silurian

Period when vascular plants appeared on the fossil record

carboniferous

period that was dominted by land plates, namely lycopods

Tracheids

primitive water conducting cells in most vascular plants

only type in most vascular plants, other than angiosperms and gnetophytes

tracherary elements

conducting cells of the zylyme with distinctive lignigied wall thickenings

vessels elements

• principal water-conducting cells in angiosperms

  • Evolved independently in several groups of vascular plants due to convergent evolution  

Lycopodiophyta

phylum of Club mosses, spike mosses, quill worts

vascular plants with a sporophyte that exhibits dichotomous branching

contains microphylls

a single strand of vascular tissue present

vascular tissue in the center of the stem

sporangia in the axils (on top) of microphylls

biflagellate or multiflagellate

dominated during the late Devonian to carboniferous period

microphylls

leaves witha small vascular bundle

a single strand of vasular tissue

dichotomous branching

the dicision or forking of an axis into two branches