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Charales are the closest relatives to the land plants. Typical liverwort growth pattern-- note the dichotomous branching pattern. CSUBIOWEB - IMAGES BY STEVEN J. WOLF.
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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.
Bazzania adnexa Hymenophyton flabellatum Liverworts are non-vascular plants Symphyogyna hymenophyllum
Marchantia foliacea Marchantia berteroana
Marchantia sp. Gemmae Cups www2.una.edu/pdavis/bryophytes.htm
Pores on the upper surface allow for gas exchange. www.botany.hawaii.edu/faculty/webb/Bot201/Marchantia www.ksu.edu/organismic/bryophytes.htm acstaff.bloomu.edu/chamuris/222/images.html
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 + formosses,hornworts,ferns & seed plants 3 introns-inliverworts and green algae
B A 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).
4. Liverworts are the first land plants. 5. Tracheophytes shared ancestors with a number of other non-vascular plant groups. 3. Land plants came from freshwater algae. 2. Land plants are monophyletic. 1. Green plants are monophyletic. From Kendrick & Crane 1997, Nature
2 types of gametes Sperm Egg Gametophyte (1n) Spore inside oogonium germinates to form new gametophyte Fertiliztion, Zygote (2n) formation, and meiosis makes 4 spores (1n)
Fern Life Cycle Mature Gametophyte Sporophyte
Fern Life Cycle Sporophyte Spores Gametophyte Gametes
There is a clear trend from a dominant gametophyte to a dominant sporophyte. Why?
Coleochaete CharaLiverwort Hornwort Moss Lycopod Fern Psilotum Horsetail Cycad From Kendrick & Crane 1997, Nature