Spore Shedding Vascular Plants Psilotum Lycopodium Equisetum Psilotum

Spore Shedding Vascular Plants Psilotum Lycopodium Equisetum

Psilotum nudum (whisk fern)

Psilotum nudum (whisk fern) http: //imagenes. infojardin. com/sube/images/cqs 1194212302 m. 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 guard cells epidermis cutin PSN cortex lignified cortex respiring cortex phloem metaxylem protoxylem

Protosteles: haplosteles actinostele plectostele Siphonosteles: siphonostele solenostele dictyostele cortex phloem xylem pith leaf gap leaf trace eustele dicot stem atactostele monocot stem

Psilotum stem specimen more than triarch http: //sols. unlv. edu/Schulte/Anatomy/Stems/Psilotum. Whole. jpg

Psilotum rhizomes with rhizoids http: //upload. wikimedia. org/wikipedia/commons/thumb/3/3 b/Psilotum_nudum_Rhizome. jpg/800 px-Psilotum_nudum_Rhizome. jpg

http: //www. dipbot. unict. it/sistematica_es/Immagini/21001. 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

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 crosssection showing: epidermis, cortex and a portion of the vascular cylinder.

http: //kentsimmons. uwinnipeg. ca/2153/Psilotum_gametophyte. jpg antheridia http: //www. siu. edu/~perspect/01_sp/pics/psilotum. jpg http: //kentsimmons. uwinnipeg. ca/2153/psilot. Anth. Low. Mag. jpg archegonium Psilotum gametophyte tissues all haploid http: //kentsimmons. uwinnipeg. ca/2153/psiloto. Archigonium. 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! 1 N gametophyte 1 N antheridium 2 N rhizome 2 N rhizoid 1 N rhizoid

Cooksonia Earliest Land Plants from the Early Devonian Rhynia