Ana səhifə

Seedless vascular plants continued Chapter 17 Phylum Pteridophyta

Yüklə 32 Kb.
ölçüsü32 Kb.

Seedless vascular plants continued

Chapter 17

Phylum Pteridophyta

  • Eusporangium

  • Large and contain many spores

  • Multicellular in origin

  • Leptosporangia

  • Arise from a single cell

  • Tapetum is two-cells-thick nutritive tissue

  • Annulus drying results in catapult-like discharge of spores


  • Eusporate ferns

  • Ophioglossales and Marattiales

  • Filicales

  • Heterosporous leptosporangiate ferns

  • Marsileales and Salviniales (water ferns)

  • Whisk ferns (Eusporate and rootless)

  • Psilotales

Order Ophioglossales

  • 3 genera (Botrychium, Ophioglossum)

  • Each leaf has a vegetative portion or blade and a fertile segment

  • Gametophytes are subterranean, tuberous, elongate and have endophytic fungi

  • Gametophytes resemble those of Psilotales


  • Look more like “ferns”

  • Six living genera of 200 species


  • Homosporous leptosporangiate

  • 10,500 species

  • Fronds are megaphylls of sporophyte

  • Fronds are divided into pinnae along rachis

  • Fiddleheads – circinate vernation leaf development

  • Sporophyte is perennial stage in ferns


  • Sporangia occur in clusters called sori in many genera



  • Bisexual gametophyte is heart-shaped prothallus with rhizoids

  • Archegonia near notch in heart

  • Antheridia near rhizoids

  • Development timing deterimines inbreeding or outcrossing frequency


Water ferns

  • Heterosporous leptosporangiate ferns

  • Marsilcales and Salviniales

Water ferns


  • Whisk ferns with two genera, Psilotum and Tmesipteris

  • Rootless and eusporangiate

  • Bisexual subterranean gametophyte with a symbiotic fungus


  • Genus Equisetum, horsetails

  • Jointed stems and rough textures

  • Homosporous

  • Sporangia are borne in groups of 5-10 along the margin of umbrella-like structures called sporangiophores, which are clustered into stroboli

  • Green, free-living gametophytes are bisexual or male

Verilənlər bazası müəlliflik hüququ ilə müdafiə olunur © 2016
rəhbərliyinə müraciət