Pityrogramma
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Authority
Proctor, George R. 1989. Ferns of Puerto Rico and the Virgin Islands. Mem. New York Bot. Gard. 53: 1-389.
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Family
Pteridaceae
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Scientific Name
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Description
Species Description - Small to medium-sized tenestrial or epipetric fems. Rhizomes short-creeping to erect, clothed with nanow, more or less attenuate, non-clathrate scales. Fronds fasciculate, all similar or subdimorphic, not articulate to the rhizome; stipes usually dark, hard, and lustrous. Blades 1- to 3-pinnate, narrowly oblong or lanceolate to ovate or deltate, usually covered on abaxial side with white or yellow to nearly orange wax-like powder, otherwise naked or rarely with scales; veins free, pinnately forked. Sori indefinite and indusium absent; sporangia produced along the course of the veins and often at maturity forming conffuent lines or masses; annulus of 20-24 cells; spores tetrahedral-globose, trilete, the surface coarsely tuberculate, reticulate, or ridged, rarely smooth and minutely granulate.
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Discussion
Type Species. Pityrogramma chrysophylla (Swartz) Link, based on Acrostichum chrysophyllum Swartz of the West Indies.
A small genus of less than 20 species, most of them occurring in the neotropical region. Puerto Rico has five species, two of them represented by quite well-marked varieties. The generic name is derived from the GreeK pityron, scurf or farina, + gramme, line; the undersurface of the fronds is covered with farina-like powder, and the sporangia are in lines along the veins.
Special Literature. Tryon, R. M . 1962. Taxonomic fem notes. II. Pityrogramma (including Trismeria) and Anogramma. Contr, Gray Herb. 189: 52-76; Tryon, R. M. & A. F. Tryon. 1982. Fems and allied plants, pp. 216-223.