Charales are the closest relatives to the land plants

Typical liverwort growth pattern-- note the dichotomous branching pattern.

CSUBIOWEB - IMAGES BY STEVEN J. WOLF Marchantia - Archegoniophores- these umbrella-shaped structures have archegonia (vessels) containing eggs on the underside of the “cap”.

CSUBIOWEB - IMAGES BY STEVEN J. WOLF

Marchantia antheridiophores - these mushroom shaped structures have antheridia (sperm producing vessels) on their upper surface.

Hymenophyton flabellatum

Symphyogyna hymenophyllum

Bazzania adnexa

Liverworts are non-vascular plants

Marchantia berteroana

Marchantia foliacea

Gemmae Cups

www2.una.edu/pdavis/bryophytes.htm

Marchantia sp.

www.ksu.edu/organismic/bryophytes.htm

Pores on the upper surface allow for gas exchange.

acstaff.bloomu.edu/chamuris/222/images.html

www.botany.hawaii.edu/faculty/webb/Bot201/Marchantia

Qiu, Y, Y. Cho, J.C. Cox and J.D. Palmer. 1998. The gain of three mitochondrial introns identifies liverworts as the earliest land plants. Nature 394: 671-674.

3 introns - in liverworts and

green algae

3 introns + for mosses,hornworts,ferns & seed plants

Two Hypotheses: Some evidence (e.g. Qiu et al. 1998 and no stomates) points to the liverworts as the earliest land plants (A); other evidence (e.g., sperm structure) points to the hornworts as the earliest land plants (B).

A

B

From Kendrick & Crane 1997, Nature

2. Land plants are monophyletic.

1. Green plants are monophyletic.

3. Land plants came from freshwater algae.

4. Liverworts are the first land plants.

5. Tracheophytes shared ancestors with a number of other non-vascular plant groups.

All Green Plants

All Land Plants

All Vascular Plants

Gametophyte (1n)

2 types of gametes

Sperm

Egg

Fertiliztion, Zygote (2n) formation, and meiosis makes 4 spores (1n)

Spore inside oogonium germinates to form new gametophyte

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Fern Life Cycle

Mature GametophyteSporophyte

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Sporophyte

Gametophyte

Spores

Gametes

Fern Life Cycle

There is a clear trend from a dominant gametophyte to a dominant sporophyte. Why?

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Coleochaete Chara Liverwort Hornwort Moss

Lycopod Fern Psilotum Horsetail Cycad

From Kendrick & Crane 1997, Nature