Thelypteris cretacea A.R.Sm.
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Authority
Mickel, John T. & Beitel, Joseph M. 1988. Pteridophyte Flora of Oaxaca, Mexico. Mem. New York Bot. Gard. 46: 1-580.
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Family
Thelypteridaceae
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Scientific Name
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Description
Species Description - Rhizome short-creeping, at apex with tan, glabrous, ovate-lanceolate scales 3-5 x 1-1.5 mm, with cells ± isodiametric or slightly elongate; fronds 20-60(-100) cm long, stipe 5-35(-50) cm long, 1.5-4(-7) mm wide, stramineous, basal scales like those of rhizome, otherwise glabrous; rachis glabrous to moderately hairy, often glabrescent; lamina 13-40(-56) cm long, 10-20 (-34) cm wide, gradually tapering distally; pinnae 5-10(-17) cm long, (0.6-)0.9-1.5(-2.1) cm wide, incised (0.5-)0.7-0.8 their width, widest at base; segments oblique, subfalcate, 2-3(-4) mm wide; veins (4-)6-9(-12) pairs per segment, lowermost meeting margin at the sinus or nearly so; costae, veins, and leaf tissue glabrous on both sides or costae with sparse to moderate pubescence up to 0.5 mm long, sometimes also with light yellowish, capitate, stipitate glands; sori supramedial; indusia glabrous to moderately hairy, sometimes also with stipitate glands; spores 34-43 µm long.
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Discussion
Type. Costa Rica. Guanacaste, Mickel 2867 (NY!; isotypes ISC!, UC!). Thelypteris cretacea is closely related to T. patens and differs from it chiefly by the decumbent rhizome. In general, it is a smaller and more glabrous plant than T patens and lacks the orangish glands along the costules that often characterize T. patens. Additional study is needed to assess the taxonomic importance of the difference in rhizome habit.
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Distribution
Along river banks; Sola de Vega; ca. 1300 m. Mexico (Ver, Oax, Chis); Guat, Salv, Nic, CR.
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