Trichomanes
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Authority
Mickel, John T. & Smith, Alan R. 2004. The pteridophytes of Mexico. Mem. New York Bot. Gard. 88: 1-1054.
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Family
Hymenophyllaceae
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Scientific Name
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Description
Genus Description - Mostly epiphytic, terrestrial (few in Mexico) or epipetric; rhizomes usually long-creeping, erect in some species, very slender, with stiff hairs; roots usually present, absent in a few species; fronds minute to small, occasionally medium-sized, generally monomorphic, rarely dimorphic, distant; stipes slender, glabrous or hairy; blades undivided to decompound, membranaceous, mostly only one cell thick, glabrous or with simple to stellate hairs (on veins and blade margins); segments mostly adnate and decurrent to next axis; sori marginal, in conical or tubular involucres, each with straight or flared, entire to bilobed mouth, immersed in laminae or exserted; receptacles growing from base, with age generally resulting in a long-exserted trichome; spores tetrahedral-globose, green, lacking conspicuous markings; gametophytes filamentous, often gemmiferous; x=32, 33, 34, 36.
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Discussion
Type: Trichomanes crispum L.
Didymoglossum Desv., Me´m. Soc. Linn. Paris 6: 330. 1827. Lectotype (chosen by C. Chr., Index Filic. XIV. 1906): Didymoglossum muscoides (Sw.) Desv. [= Trichomanes muscoides Sw.] = Trichomanes hymenoides Hedw. For additional synonymy, see Morton, 1968.
Trichomanes is a pantropical genus of over 300 species, of which about 100 are American, with 26 in Mexico. The genus was divided by Copeland (1938) into many genera, but splitting seems to compound the problem of generic delimitation in the filmy ferns, rather than alleviate it. The genus is distinct by its mostly one-cell-thick blades, tubular or conical involucres, and strongly exserted receptacles.