Plant Evolution and Phylogenetics: Key Terms and Concepts

Embryophytes

Land plants that exhibit alteration between sporophyte (2N) and gametophyte (N), have thick-walled spores, embryonic stage, structures to protect gametes (archegonia and antheridia), and a cuticle.

Tracheophytes

Vascular plants, most of which are angiosperms (flowering plants).

Archaeplastida

Plants in the broad sense characterized by primary endosymbiosis, chloroplast, and chlorophyll A.

Glaucophytes

Microscopic algae.

Rhodophytes

Red algae.

Viridiplantae

vGreen plants characterized by chlorophyll B (and A), storage of carbs in the form of starch, and two anterior flagella at some stage in life cycle.

Chlorophytes

Green algae with synapomorphies including clockwise rotation of flagella.

Haplo-diplontic life cycle

A life cycle involving both haploid and diploid stages.

Streptophytes

Includes Charophytes and land plants with nuclear spindles oriented perpendicular to cell wall.

Charophytes

Synapomorphies include apical growth, flavonoids, precursor to cuticle, and retention of egg or haploid parent plant in gametangia.

Haplontic life cycle

Life cycle where most time is spent in haploid stage.

Bryophytes

Non-vascular plants including liverworts, hornworts, and mosses.

Gametophyte dominant

A life cycle where the gametophyte is the dominant form.

Hornworts

Characterized by thalloid gametophyte, stomata with guard cells, mucilage cells in thallus, and meristem at base of sporophyte.

Liverworts

Characterized by oil bodies, epidermal pores, simple sporophyte, and can be monoecious or dioecious.

Mosses

Characterized by operculate capsules with peristomes, gametophyte leaves with midrib, and can be monoecious or dioecious.

Sister groups

Closest relatives on a phylogenetic tree.

Morphology

Traits of form or structure.

Derived Traits

Traits developed in a lineage that are different from their ancestors.

Monophyletic Group

A group composed of an ancestor and all its descendants, also called a clade.

Synapomorphies

Character states that have arisen in the ancestor of the group and are present in all of its members.

Paraphyletic Group

Branches next to each other on the phylogenetic tree.

Nomenclature

Latin binomial consisting of generic name, specific epithet, and authority.