The morphological and anatomical reinvestigation of the Psilotum nudum, in Hyrcanian forests, N Iran

Psilotum nudum is an ancestral epiphytic of the monilophytes which has been recently reported from hyrcanian forests. it was already introduced as an epiphytic species from some patchy habitats in the lowland parts of hyrcanian forests. moreover, psilotum nudum was reviewed using morphological and anatomical characteristics in two different populations in central parts of hyrcanian zone. the results showed that there were no significant differences between morphological and anatomical characteristics. the aerial stems of the plant were linear, chlorophyllous, and dichotomously branched. leaves were much reduced, simple, scale-like, and without ligules. synangium was composed of 3-locular capsule-like sporangia. also, stele type in apex aerial stem and aerial stem was actinostele; and it was haplostele type in rhizome. in this paper, a new locality of this species growing on the rocky sites was reported in ata-kuh of guilan.