Blechnum meridense Klotzsch
Descripción
Differing from B. gracile in the lateral pinnae ± equalling the terminal pinna in length, usually 2(–3) pairs, lateral and terminal pinnae narrowly cuneate proximally, sessile or slightly adnate, lacking confluent or separate semicircular lobes at the base of the terminal pinna; 2n=62 (Trin).
A
A
Forma de vida
TerrestreA
Ejemplar revisado
Chis (Breedlove 32982, 42005, DS, MEXU).A
Elevación
800 mA
Ecología y Hábitat
In lower montane and montane forests.A
Categoría IUCN
No incluidaB
Categoría NOM-059-SEMARNAT-2010
No incluidaC
Discusión taxonómica
The two collections cited, especially Breedlove 42005, are indistinguishable from many specimens seen from Venezuela. Of Mexican species, B. meridense most closely resembles B. gracile and the hybrid between B. gracile and B. occidentale. On each blade there are two (to three) pairs of lateral pinnae and the terminal pinna is about the same size as the lateral ones. All the pinnae are narrowed and more or less narrowly cuneate at their bases.
Blechnum meridense has usually been called B. fraxineum Willd., but as Mickel and Beitel (1988) discussed, the name fraxineum applies to the hybrid between B. gracile and B. meridense, and is not yet known from Mexico. Diploid B. meridense, although apparently absent itself in Jamaica, forms sterile triploid hybrids with B. occidentale s.l. in that country, and Trinidad, according to Walker (1966, 1973, 1985); these triploids can form large populations through vegetative reproduction by stolons. If this is true, the situation begs explanation.
Hybrids between B. meridense and B. occidentale are distinguishable by having an intermediate number of pinna pairs (ca. 5–8), subconform blade apices almost as long as the lateral pinnae, fully pinnate blade bases, and distant median pinnae (thus eliminating B. polypodioides as a possible parent). These hybrids occur in South America and Costa Rica, whereas the pubescent hybrid B. appendiculatum X meridense (= B. X antillanum Proctor) occurs in Jamaica and South America.A
Blechnum meridense has usually been called B. fraxineum Willd., but as Mickel and Beitel (1988) discussed, the name fraxineum applies to the hybrid between B. gracile and B. meridense, and is not yet known from Mexico. Diploid B. meridense, although apparently absent itself in Jamaica, forms sterile triploid hybrids with B. occidentale s.l. in that country, and Trinidad, according to Walker (1966, 1973, 1985); these triploids can form large populations through vegetative reproduction by stolons. If this is true, the situation begs explanation.
Hybrids between B. meridense and B. occidentale are distinguishable by having an intermediate number of pinna pairs (ca. 5–8), subconform blade apices almost as long as the lateral pinnae, fully pinnate blade bases, and distant median pinnae (thus eliminating B. polypodioides as a possible parent). These hybrids occur in South America and Costa Rica, whereas the pubescent hybrid B. appendiculatum X meridense (= B. X antillanum Proctor) occurs in Jamaica and South America.A