PTERIDOFITAS EXTINTAS O RARAS DEL VALLE DE MÉXICO

Abstract

The Valle de México have 113 species of
pteridophytes, 18 species are extinct in
the zone and 19 species are rare or few
frequent, belong 23 genera and 37 species
according IUCN (1994). We revised 1400
specimens of pteridophytes collected in
fiels and exemplaries of national and international herbarium as ENCB, MEXU,
CHAPA, P, K, LP, SI, MO. We found some
species which were living in the zone in
the century XIX and first middle century
XX and now these species there are not in
the area as Adiantum capillus-veneris L.,
Asplenium exiguum Beddome, Asplenium
palmeri Maxon, Blechnum glandulosum
Kaulf. & Link, Cheilanthes mexicana Davenp., Cheilanthes microphylla (Sw.) Sw.,
Cheilanthes notholaenoides (Desv.) Maxon
& Weath., Pityrogramma ebenea (L.) Proctor, Polypodium polypodioides (L.) Watt var.
aciculare Weath., Polypodium rosei Maxon,
Psilotum nudum (L.) Beauvais, Selaginella
peruviana (Milde) Hieron., Selaginella
wrightii Hieron., Selaginella arsenei Wea-
th., Terpsichore delicatula (M. Martens &
Galeotii) A.R. Sm. and Woodsia mexicana
Fée, the vouchers of these specimens were
realized in place now occupied by colonies
and commercial centers. The aquatic habitats and the aquatic pteridophytes were
disappearing as Azolla mexicana C. Presl,
Marsilea mollis B.L. Robinson et Fernald.
Some species as Anogramma leptophylla
(L.) Link, Asplenium fibrillosum Pringle
&Davenp. & Davenp., Athyrium bourgeaui
E. Fourn., Blechnum stoloniferum (Mett. &
E. Fourn.) C. Chr., Bommeria subpalacea
Maxon, Botrychium schaffneri Underw. var.
schaffneri, Campyloneurum amphostenon
(Kunze & Klotzsch) Fée, Elaphoglossum
engelii (H. Karst.) H. Christ., Elaphoglossum erinaceum (Fée) T. Moore var. occidentale Mickel, Elaphoglossum glaucum T.
Moore, Elaphoglossum minutum (Pohl &
Fée) T. Moore, Isoëtes mexicana Underw.,
Pecluma alfredii (Rosenst.) M.G. Price
var. cupreolepis (A.M. Evans) A.R. Sm.,
Plagiogyra pectinata (Liebm.) Lellinger,
Polypodium californicum Kaulf., Polystichum fournieri A.R. Sm., Polystichum
rachichlaena Fée, Selaginella delicatissima
Linden ex A. Braun, Selaginella rupincola
Underw., Thelypteris puberula (Baker) C.V.
Morton var. puberula were collected during
years 1960 to 1985 and after there are not
found in the zone, but there are ambiental
conditions and can be collected other time.
Collects of Schaffner, Pringle, Purpus,
Lyonnet, show pteridophytes from Mixcoac,
Tlalpan, Pedregal de San Angel, Santa Fe,
and now there are not more. These show
biodiversity lost of 32.7% of species in less
than a century.