Nonvascular Plants: Mosses, Liverworts, and Hornworts

Concepts

3 Major Groups of Plants

Nonvascular Plants

Vascular Cryptograms IMG_1314

Spermatophytes IMG_1313

These plants have neither vascular tissue nor seeds

Nonvascular plants were the first true plants to be discovered

Ex. Mosses, liverworts, and hornworts

Ex. Clubmosses, scouring rushes, and ferns

Ex. Cycads, conifers, angiosperms

These plants have both vascular tissue and seeds

These plants have vascular tissue but not seeds

Characteristics of Nonvascular Plants

Division Bryophyta IMG_1312

Division Hepatophyta

Division Anthocerotophyta

Hornworts IMG_1310

A group of small, inconspicuous thalloid plants that grow on moist soil, hidden by grasses and other herbs

They are found on roadside cuts and stable eroded soil in shade

A unique feature of the hornworts is the presence of a single large chloroplast

Liverworts IMG_1311

Small plants that have an alternation of heteromorphic generations

Sporophyte Generation

2 Basic Groups of Hepatic Gametophytes:

Thallose liverworts

Leafy liverworts

Mosses

Their bodies are composed of true parenchyma

Mostly terrestrial and have a cuticle over much of their bodies

Gametophytes are larger and occur inside pollen grains and ovules

Sporophytes are much smaller and have leaves and roots

Occur in all parts of the world and in almost every environment

Morphology

Gametophores

The leafy stem of many moss plants that grow close together, tightly appressed and forming dense mounds

Water Transport

Hydroids

Conduct water and dissolved materials

Leptoids

Involved in carbohydrate conduction

Rhizoids

Involved in allowing plants to migrate laterally

In both of these groups, the gametophyte phase is initiated when spores germinate and establish a small, temporary protonematal phase

Elaters

Single, elongate cells with spring-shaped walls. When the sporangium opens, the elaters uncoil pushing spores out

All liverworts=homosporous

The gametophyte is parenchymatous. They're always thin on the edges, and the center is more than 5 cells thick

The sporophytes have a foot and basal meristem, which makes them different from other plants

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