Blechnum
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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
Blechnaceae
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Scientific Name
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Description
Species Description - Terrestrial or occasionally epiphytic fems of small to medium size. Rhizomes ascending to erect, sometimes trunklike, or else more or less elongate and scandent, usually densely clothed with scales, sometimes stoloniferous. Fronds mostly 1 -pinnate or rarely simple, usually glabrous, and either all of similar form (monomorphic) or else dimorphic with the divisions of the fertile fronds strongly contracted; veins usually free except for the fertile veinlets. Sori elongate-linear, usually continuous, bome near or against the costa on an elongate transverse veinlet parallel to the costa; indusium narrowly linear, continuous or nearly so, firm, opening toward the costa; paraphyses absent; sporangia with annulus of 14-28 cells; spores ellipsoid, monolete, the surface nearly smooth to papillate, occasionally with minute spherical granules.
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Discussion
Type Species. Blechnum occidentale Linnaeus of the American tropics.
A large, worldwide genus of perhaps 180 species, the majority occurring in the southem hemisphere. Seven species and one quite wellmarked hybrid have been found in Puerto Rico; none of these is endemic. The generic name is from the Greek blechnon, an ancient name for fems in general. It is often noticed that the young developing fronds of these plants are strongly tinged with red. This is due to the presence of 3-deoxyanthocyanins, whose function is not known. Similar pigments occur in the genus Adiantum, and in a few other genera.
Special Literature. Broadhurst, J. 1912. The genus Struthiopteris and its representatives in North America. Bull. Torrey Bot, Club 39: 257-278, 357-385; Crowden, R. K. & S. J. Jarman. 1974, 3-Deoxyanthocyanins from the fem Blechnum procerum, Phytochem, & Phytobiol. 13: 1947-1948; Tryon, R. M . & A. F. Tryon. 1982. Fems and allied plants, pp. 669-680, 31 figs.