Ch 17: Seedless Vascular Plants

Oldest known vascular plant

cooksonia

What time period did ferns show up?

290-354 mya, carbinferous era

Dominant generation for seedless vascular plants?

Sporophyte

Different types of steles

Protostele

Siphonostele

Eustele

Protostele

simplest most ancient

solid cylinder

in most roots

Siphonostele

central pith surrounded by vascular tissue

stems of seedless vascular plants

Eustele (seed plant stems(

Evolved from protostele

Types of Leaf Evolution and associations

Microphylls - small leaves w/ single vascular strand (protostele)

Megaphylls - large leaves w/ branching vascular strands (siphonostele and eustele)

Reproduction of Seedless Vascular Plants

Homospory - produce 1 kind of spore

Heterospory - produce 2 kinds of spores

Hetereospore types

Microspore - develops into male gametophyte (sperm-producing)

Megaspore - develops into a female gametophyte (egg-producing)

Extinct seedless vascular plant characteristics

Branching stems and rhizomers, no roots or leaves

Phylum Lycopodiophyta Characteristics

Protostelic stems and leaves

Has microphylls

3 Major Genra of Lycopodiophyta

Lycopodium (club moss)

Selaginella (spike moss)

Isoetes (quillworts)

Life Cycle of Lycopodium (type of spore, gametophyte, and mechanism of fertilization)

Homosporous (1 spore type)

Give rise to bisexual gametophytes (bear both antheridia and archegonia)

Water is needed for fertilization

Life Cycle of Selaginella

Heterosporous (2 spore types)

Microspores and Megaspores, usual heterosporous production

Phylum Monilophyta: 3 Groups

Order Psilotales (Whisk fern)

Order Equisetopsida (Horsetails)

Class Polypodiopsida (Ferns)

Order Pstiotales (Whisk Ferns) Characteristics

Simple, primitive

No root or leaf

Homosporous

Protostelic

Order Equisetopsida (Horsetails) characteristics

Accumulate silica in stems

Microphylls

Homosporous

Sporangia on sporangiophores

Horsetail gametophytes are

Free-Living

Class Polypodiopsida (Fern) Characteristics

Homosporous

Have megaphyll (frownd)

Sporangia in clusters called sori, covered by indusia

Gametophytes of ferns have

both archegonia and antheridia