BIOL 112 – Chapter 29

The Non-seed Plants

Defining Kingdom Plantae

•     Multicellular, photosynthetic autotrophs

•     Cell walls of cellulose, starch for storage

•     Terrestrial, obtain nutrients from soil, oxygen and CO₂ from air through stomata

•     Produce lignin and sporopollenin

•     Internal fertilization (embryophytes)

•     Alternation of generations

Bryophytes

•      Represent the most “primitive” embryophytes

•      Male gametophytes Þ antheridia

•      Female gametophytes Þ archegonia

•      Sporophytes Þ sporangia

•      Water required for fertilization

•      No lignin

•      Three Divisions: Bryophyta, Hepatophyta, Anthocerophyta

Bryophyta - Mosses

•      Form mats of tightly packed plants

•      No true stems, leaves or roots

•      Both gametophyte and sporophyte are large

•      Sphagnum ecologically important

Hepatophyta - Liverworts

•      Inconspicuous, lobe-shaped thallus

•      Almost never far from water

•      Reproduce like mosses

•      Asexual reproduction by gemmae in gemmae cups

Anthocerophyta
Hornworts

The Vascular Plants - Tracheophytes

•     True roots, stems and leaves

•     Vascular tissue (xylem & phloem)

•     Lignification (in trees and larger vascular plants)

Seedless Vascular Plants – Ferns & Fern Allies

•      Large, leafy sporophytes; small, inconspicuous gametophytes

•      Flagellated sperm

•      Homosporous species – one spore type, bisexual gametophytes

•      Heterosporous species – Megaspores Þ female gametophytes; microspores Þ male gametophytes.

•      3 divisions – Lycophyta, Sphenophyta, Pterophyta

Lycophyta – Club Mosses

•      Abundant in the fossil record in both woody and non-woody forms.

•      Grow close to ground in temperate regions, as epiphytes in tropics.

•      Small leaves, some specialized as sporophylls.

•      Gametophytes inconspicuous, non-photosynthetic, nurtured by symbiotic fungi.

•      Homosporous or heterosporous

•      Two prominent genera: Lycopodium & Selaginella.

Sphenophyta - Horsetails

•      Abundant in fossil record, some up to 15 m tall!

•      Ribbed stems with silica, reduced leaves in whorls.

•      Sporangia borne in strobili at tip of stems.

•      Prefer moist locations in most cases

•      Homosporous, gametophytes minute, photosynthetic.

•      A single extant genus, Equisetum

Pterophyta - Ferns

•     Well represented in the tropics, many extant, greatest diversity in tropics.

•     Ferns often with very large leaves (fronds) often highly divided.

•     Small to as large as small trees (tree ferns).

•     Sporangia on underside of fronds, arranged in sori, covered in various ways or naked.

The Non-seed Plants

•     Nonvascular Plants

–   Division Bryophyta

–   Division Hepatophyta

–   Division Anthocerophyta

•     Seedless Vascular Plants

–   Division Lycophyta

–   Division Sphenophyta

–   Division Pterophyta