10/30/2011 Pteridophyte reproduction Modified 17-13 (19-9) Embryophytes Pteridophyta “Bryophytes” To be cont. To Liverworts Hornworts Mosses Rhynia (Fossil) Rhynia Lycopodiophyta microphylls megaphylls Transition to land Microphylls • One vascular trace – No branching vasculature in leaf – Forms from protostele http://28.media.tumblr.com/tumblr_lgpco8M9Ie1 qa2aauo1_500.jpg 1 10/30/2011 Megaphylls – Branching vascular traces (veins) in leaves – Typically large http://intro.bio.umb.edu/111- 112/OLLM/112s99/phyla/plants/pterophyta.jpg Are not always large. Highly reduced megaphylls in Equisetales. http://www.missouriplants.com/Ferns/E quisetum_hymenale_stems.jpg Remember the STELES Pteridophyta 2 10/30/2011 Stele modification in Pteridophyta (a few with eustele) eustele siphonostele ancestor had protostele, like Lycopodiophyta. Protosteles Lycopodiophyta Siphonosteles Most ferns, though, have siphonosteles with leaf gaps 3 10/30/2011 Eusteles Equisetales—eusteles; convergent with seed plants. Modification of life cycle and reproduction in Pteridophyta Heterosporous ferns Filicales endosporic gametophyte heterospory Eusporangiate ferns Equisetales leptosporangia above-ground photosynthetic above-ground photosynthetic gametophyte gametophyte ancestor had dominant homosporous sporophyte with underground non-photosynthetic gametophyte, like Lycopodiaceae Life cycles: above-ground photosynthetic gametophyte 4 10/30/2011 Modification of life cycle and reproduction in Pteridophyta 2. Leptosporangia Heterosporous ferns Filicales endosporic gametophyte heterospory Equisetales Eusporangiate ferns leptosporangia above-ground photosynthetic gametophyte ancestor had dominant homosporous sporophyte with underground non-photosynthetic gametophyte, like Lycopodiaceae Life cycles: eusporangia vs. leptosporangia Eusporangia: large 1 to 1000’s of spores the basal (primitive) condition walls several cells thick found in most land plants Leptosporangia: small 64 spores walls one cell thick have annulus (thickened ring) grouped into sori (sing. sorus) only in Filicales and heterosporous ferns Life cycles: eusporangia 5 10/30/2011 Life cycles: eusporangia in a eusporangiate fern (Botrychium) Life cycles: leptosporangia Life cycles: leptosporangia in Filicales http://www.google.com/imgres?q=leptosporangia+in+filicales&hl=en&clie http://t0.gstatic.com/images?q=tbn:ANd9GcQ5dCnB8I61yQSkLGFZHRNK9s nt=firefox-a&hs=HLb&sa=X&rls=org.mozilla:en- zAhC4CieR19Yvgi78YQTs01RUurg US:official&biw=748&bih=393&tbm=isch&prmd=imvns&tbnid=cDA5fNilc 4DjaM:&imgrefurl=http://www.increasemyvocabulary.com/definition/of/le ptosporangium/&docid=UL- NACsnDhf5jM&imgurl=http://farm3.static.flickr.com/2127/2263445746_6 1832fff71.jpg&w=500&h=375&ei=-2OsTtbwC62rsALHi8WADw&zoom=1 6 10/30/2011 Life cycles: leptosporangia grouped into sori in Filicales (Thelypteris) http://t2.gstatic.com/images?q=tbn:ANd9GcR67ZaOrG_IZnVCT JlKNnzNb9xRzv2WRyzTn65QY9_qNAtdmw-d Life cycles: leptosporangia grouped into sori in Filicales (Asplenium) http://t2.gstatic.com/images?q=tbn:ANd9GcRa-R- awiaCHFAk1U2wWgyE4uwVRf-2z5DuiTDyJ5trjRpP7kMP Modification of life cycle and reproduction in Pteridophyta 3. Heterospory and endosporic gametophytes Heterosporous ferns Filicales endosporic gametophyte heterospory Equisetales Eusporangiate ferns leptosporangia above-ground photosynthetic gametophyte ancestor had dominant homosporous sporophyte with underground non-photosynthetic gametophyte, like Lycopodiaceae 7 10/30/2011 Life cycles: heterospory The life cycle of Selaginella is the same as that found in the heterosporous ferns and in the seed plants. Embryophytes Pteridophytes “Bryophytes” To be cont. To Liverworts Hornworts Mosses Rhynia (Fossil) Rhynia Lycopodiophyta megaphylls Transition to land Equisetales: brief overview --highly reduced megaphylls --eusteles --homosporous --eusporangia --above-ground photosynthetic gametophyte --strobili --hollow, jointed stems embedded with silica --one genus, Equisetum, about 15 species; 8 10/30/2011 Equisetales: Equisetum Equisetales is the only fern group with strobili. Strobili are stems with modified leaves– spppyorophylls—clustered on them. These sporophylls are often called sporangiophores on Equisetum. http://www.sbs.utexas.edu/bio406d/images/pics/ equ/Equisetum%20hyemale%20strob1.jpg Equisetum: strobili 9 10/30/2011 Embryophytes Pteridophytes “Bryophytes” To be cont. To Liverworts Hornworts Mosses Rhynia (Fossil) Rhynia Lycopodiophyta megaphylls Transition to land Eusporangiate ferns: brief overview --megaphylls --protosteles --homosporous --eusporangia --underground, non-photosynthetic gametophyte --includes Psilotales and Ophioglossales --7 genera, about 70 species Eusporangiate ferns: Ophioglossales: Botrychium What you’re seeing here is one leaf http://www.rook.org/earl/bwca/nature/ferns/botrychium- multifidum-1sm.jpg 10 10/30/2011 Eusporangiate ferns: Ophioglossales: Ophioglossum http://hengduan.huh.harvard.e du/fieldnotes/photos/show_ima ge?image_id=1140 Eusporangiate ferns: Psilotales: Psilotum http://t0.gstatic.com/images?q=tbn:ANd9GcRN0J vXD52gT892P9oJD7fNeMmehdMwcUyqLf8yF_A TVFbdvvh0 Embryophytes Pteridophytes “Bryophytes” To be cont. To Liverworts Hornworts Mosses Rhynia (Fossil) Rhynia Lycopodiophyta megaphylls Transition to land 11 10/30/2011 Heterosporous ferns: brief overview --all aquatic --megaphylls --siphonosteles --heterosporous --leptosporangia --endosporic gametophyte --includes Marsileales and Salviniales --5 genera, about 70 species Heterosporous ferns: Salviniales: Azolla http://nas.er.usgs.gov/XIMAGESERVERX/2007/20071004180006.jpg Heterosporous ferns: Salviniales: Salvinia 12 10/30/2011 Heterosporous ferns: Marsileales: Marsilea Embryophytes Pteridophytes “Bryophytes” To be cont. To Liverworts Hornworts Mosses Rhynia (Fossil) Rhynia Lycopodiophyta megaphylls Transition to land Filicales: brief overview --megaphylls --siphonosteles (mostly) – few with eusteles --homosporous --leptosporangia --above-ground, photosynthetic gametophyte --about 320 genera, 10,500 species 13 10/30/2011 Filicales: Dennstaedtia Filicales: Pteridium http://t2.gstatic.com/images?q=tbn:ANd9GcQSnzinzDmcXng7WDPh3- KaypqI3JJUDSxUWSbyCjSa91eTqQOzcg 14.