Análisis de la distribución de las especies de helechos y afines del valle de México, notas ecológicas y florísticas

an analysis of distribution for 40 genera and 113 species of pteridophytes from the valley of mexico according vegetation's types of rzedowski (2001) is presented. we found 54% of the species in cloud forest; 45% in conifers forests; 33.6% in quercus forest; 34.5% in grasslands; 28% in xero-philous scrubs; 22% in pine-oak forest; 3.5% in quercus scrub and 1.8% in aquatic vegetation as in halophyllous vegetation. the affinities between the pteridophytes of the different communities were analyzed using presence/absence data with the s？rensen's similarity index and upgma method to construct the dendrogram, and we found more similarity between pinus forest and the abies forest. quercus forest is related to the cloud forest, and the xerophilous scrubs is similar with glassland. the hallophyllous vegetation has little relation with another communities and the aquatic vegetation has not relation with any other.