Monographs Details:
Authority:
Acevedo-RodrÃguez, Pedro & collaborators. 1996. Flora of St. John, U.S. Virgin Islands. Mem. New York Bot. Gard. 78: 1-581.
Acevedo-RodrÃguez, Pedro & collaborators. 1996. Flora of St. John, U.S. Virgin Islands. Mem. New York Bot. Gard. 78: 1-581.
Family:
Pteridaceae
Pteridaceae
Description:
Genus Description - Small to large, coarse terrestrial ferns. Rhizomes creeping to erect, often stout and woody, clothed with scales at the apex. Fronds usually clustered, erect or arching, monomorphic or sometimes dimorphic, often long-stipitate; stipes narrowly grooved adaxially; blades 1- to 4-pinnate, elongate or pentagonal in outline, sometimes each of the basal pinnae as large as rest of the blade; midveins of penultimate divisions deeply but narrowly grooved adaxially, the parallel ridges often bearing minute spinelike awns, one each at the base of the ultimate midveinlets; venation free or reticulate; areoles without free included veinlets. Sori linear, marginal, the sporangia borne in a continuous line on a delicate transverse commissure connecting the ultimate vein-tips; paraphyses usually present and often numerous; indusium linear, continuous, formed by the modified reflexed margin, opening inwardly; sporangia with annulus of 16-34 cells; spores tetrahedral or globose, trilete, usually with a prominent equatorial flange, the surfaces tuberculate or reticulate.
Distribution and Ecology - A genus of perhaps 280 species, most of which are tropical.
Genus Description - Small to large, coarse terrestrial ferns. Rhizomes creeping to erect, often stout and woody, clothed with scales at the apex. Fronds usually clustered, erect or arching, monomorphic or sometimes dimorphic, often long-stipitate; stipes narrowly grooved adaxially; blades 1- to 4-pinnate, elongate or pentagonal in outline, sometimes each of the basal pinnae as large as rest of the blade; midveins of penultimate divisions deeply but narrowly grooved adaxially, the parallel ridges often bearing minute spinelike awns, one each at the base of the ultimate midveinlets; venation free or reticulate; areoles without free included veinlets. Sori linear, marginal, the sporangia borne in a continuous line on a delicate transverse commissure connecting the ultimate vein-tips; paraphyses usually present and often numerous; indusium linear, continuous, formed by the modified reflexed margin, opening inwardly; sporangia with annulus of 16-34 cells; spores tetrahedral or globose, trilete, usually with a prominent equatorial flange, the surfaces tuberculate or reticulate.
Distribution and Ecology - A genus of perhaps 280 species, most of which are tropical.