220 likes | 945 Views
Spore Shedding Vascular Plants. Psilotum Lycopodium Equisetum. Psilotum nudum (whisk fern). Psilotum nudum (whisk fern). http://imagenes.infojardin.com/sube/images/cqs1194212302m.jpg.
E N D
Spore Shedding Vascular Plants Psilotum Lycopodium Equisetum
Psilotum nudum (whisk fern) http://imagenes.infojardin.com/sube/images/cqs1194212302m.jpg
Psilotum has a stem doing virtually all the photosynthesis, with dichotomous branching, enations without vascular tissue, and yellow synangia in the axils of the enations. Below ground, the stem is not photosynthetic but the epidermis forms rhizoids for anchorage. The plant thus lacks roots and leaves with underground stem (rhizome) doing the anchorage functions.
Psilotum stem cross section radial exarch triarch actinostele cutin guard cells epidermis PSN cortex lignified cortex respiring cortex phloem metaxylem protoxylem
Protosteles: haplosteles actinostele plectostele cortexphloemxylem Siphonosteles: siphonostele solenostele dictyostele cortexphloemxylem pith leaf gap leaf trace eustele atactostele dicot stem monocot stem
Psilotum stem specimen more than triarch http://sols.unlv.edu/Schulte/Anatomy/Stems/PsilotumWhole.jpg
Psilotum rhizomes with rhizoids http://upload.wikimedia.org/wikipedia/commons/thumb/3/3b/Psilotum_nudum_Rhizome.jpg/800px-Psilotum_nudum_Rhizome.jpg
Psilotum rhizome cross-section http://www.dipbot.unict.it/sistematica_es/Immagini/21001.JPG
Psilotum stem demonstrates dichotomous branching, enations (no vascular tissue) and two of the three sporangia in a single synangium http://www.dipbot.unict.it/sistematica_es/Immagini/21001.JPG
Psilotum sporangium (a three-parted synangium) This specimen has shed its spores into the wind and so the sterile jackets are empty. At the bottom of the view is a partial stem cross-section showing: epidermis, cortex and a portion of the vascular cylinder.
http://kentsimmons.uwinnipeg.ca/2153/Psilotum_gametophyte.jpghttp://kentsimmons.uwinnipeg.ca/2153/Psilotum_gametophyte.jpg antheridia http://www.siu.edu/~perspect/01_sp/pics/psilotum.jpg Psilotum gametophyte tissues all haploid http://kentsimmons.uwinnipeg.ca/2153/psilotAnthLowMag.jpg archegonium http://kentsimmons.uwinnipeg.ca/2153/psilotoArchigonium.jpg
Psilotum gametophyte (SE to NW) and sporophyte (Y-shape) The photo is flipped and cropped. Some versions of Powerpoint may fail to retain this making the labels erroneous! 1N gametophyte 1N antheridium 2N rhizome 2N rhizoid 1N rhizoid
Cooksonia Rhynia Earliest Land Plants from the Early Devonian