Vascular Plants

Innovaons of early (non-seed) vascular plants

LYCOPHYTES Extantland charophytes plants 8,500 liverworts 10,000 mosses plants land 100 hornworts 1,200 lycophytes 12,000

ferns 300 plants vascular cycads Slide courtesy Slide of Sarah Mathews, Univ. Harvard 1 Ginkgo 90 Gnetales plants seed 700 conifers 300,000

angiosperms Vascular plant lineages

LAND PLANTS NON-VASCULAR PLANTS Hepaticophyta (liverworts)

Bryophyta (mosses)

Anthocerophyta (hornworts)

VASCULAR PLANTS SEEDLESS PLANTS Lycophyta (lycophytes)

Psilotophyta (whisk ferns)

Equisetophyta (horsetails)

Pteridophyta (ferns)

SEED PLANTS GYMNOSPERMS Cycadophyta (cycads)

Ginkgophyta (ginkgo)

ConifersRedwood group (junipers et al.)

Pinophyta (pines et al.)

Gnetophyta (gnetophytes)

ANGIOSPERMS Anthophyta (angiosperms) Lycophytes were abundant and massive during the Carboniferous (~300mya)

• Sporophyte is dominant, becomes free living and long-lived, and is substanally larger than the gametophyte • Branched sporophyte– more capacity for photosynthesis and reproducon.

• Fluid-conducng (vascular) systems: xylem (water and minerals) and phloem (food transport)

• Ligniﬁed secondary walls; added rigidity to plant organs and ssues • Diﬀerenaon of sporophyte into shoot (true stem and leaves) and roots (with endodermis)

Conducve cells of vascular plants: Xylem and Phloem TREND: Lycophytes have Protosteles

Cronk 2.15 Lycophytes have microphylls

microphyll

leaf trace stem long. section

stem cross section

leaf cross section Lycophyte sporophytes a c

a. Isoetes b. Selaginella

c. Lycopodium d. Huperzia

b d Lycophyte Gametophytes

under ground above ground dependent on symbiotic fungus photosynthetic

hp://www.csupomona.edu/~jcclark/classes/bot125/resource/graphics/lyc_lycopodium_gametophyt.html Sporangia

A B

Angel Maden

hp://www.arthurhaines.com/Florae_Novae_Angliae/Lycopodiaceae/Lycopodium-obscurum-strobilus.jpg Heterospory has evolved within Lycophytes Homosporous = one type of sporangium produces one type of spore, which produces a bisexual gametophyte. - Lycopodiaceae (Huperzia, Lycopodium)

George Shepherd Heterosporous = two types of sporangia (micro- and megasporangium) produce two types of spores (micro- and megaspores), which produce male (micro-) and female (mega-) gametophytes, respecvely. - Isoetes, Selaginella

hp://www.botany.hawaii.edu/faculty/webb/BOT311/BOT311-00/LycoRepro/LycoRepro-1.htm hp://bot.botany.wisc.edu/Resources/Botany/Lycophytes/ TREND: Homospory to Heterospory

Heterospory evolved independently in ______, ______and______Selaginella Selaginella Life Cycle Isoetes

hp://www.plantsystemacs.org/users/robbin/10_6_05/upload98/Isoetes_lithophila.JPG Isoetes Gametophytes

hp://www.plantsystemacs.org/imgs/robbin/r/Isoetaceae_Isoetes_riparia_36071.html

hp://www.plantsystemacs.org/imgs/robbin/r/ Isoetaceae_Isoetes_riparia_36073.html Unique Features of Lycophytes • Sporophytes: – Leaves are microphylls – Dichotomous branching (from apical meristem) in stems and roots – Stem and roots have protosteles – Primary root system is lost; advenous roots originate from inside stem (from the pericycle) – Sporangia are associated with leaves called sporophylls; organized into a strobilus (cone) or concentrated on areas of the stem.

• Gametophyte: – minute, photosynthec or not, oen associated with fungus; may have rhizoids – bisexual with antheridia and archegonia (in homosporous lycophytes) or unisexual and endosporic (heterosporous lycophytes) Vocabulary Tracheids, vessel elements Sieve cell, sieve tube member Stele, protostele Microphyll Sporophyll Strobilus/ strobili Dichotomous branching Endodermis, pericycle Advenous roots Heterospory: microsporangia (microspores, microgametophytes), megasporangia (megaspores, megagametophytes) Endosporic gametophyte