Sticherus underwoodianus (Maxon) Nakai
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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
Gleicheniaceae
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Scientific Name
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Description
Species Description - Rhizomes long-creeping, with castaneous ciliate scales 1.5–2.5 x 0.2–0.3 mm; stipes 1.5–2 mm diam.; main axes beyond first fork dormant or eventually continuing, scaly to glabrescent, often also with a pair of stipules at the proximal fork; dormant buds with brown to orangish brown, long-ciliate scales 1.5–3 x 0.2–0.5 mm; pinnae mostly 3–5 times pseudodichotomously forking; axes below ultimate forks usually pectinate on both sides; penultimate segments 1.2–3(–3.5) cm wide, the costae with dense orange-tan, spreading, ciliate scales 1–2 x 0.3–0.5 mm; ultimate segments chartaceous to subcoriaceous, narrowly deltate, to ca. 1.5 cm x 2–3 mm at mid-segment, revolute, abaxially glabrous and lacking arachnoid hairs, but with simple or branched white or yellowish hairs (reduced scales) 0.5–0.8 mm long on veins, also with scales on costules similar to those of costae, but smaller; sori medial to supramedial, with 3–5 sporangia per sorus.
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Discussion
Dicranopteris underwoodiana Maxon, N. Amer. Fl. 16: 59. 1909. Gleichenia underwoodiana (Maxon) C. Chr., Index Filic., Suppl. 1: 44. 1913. Type. Mexico. Chiapas: Ghiesbreght 271 (NY!; isotypes BM!, GH!, K!, NY!, PH!, US!).
This species can generally be distinguished from congeners in Mexico by its narrower pinnae and occurrence at higher elevations. The type has pinnae 3–3.3 cm wide, whereas most Mexican material is 1.5–2.5 cm wide. Sticherus underwoodianus resembles S. jamaicensis (Underw.) Nakai of Cuba, Jamaica, and Hispaniola, and Smith (1981) suggested they might be conspecific. They do indeed appear to be nearest allies, but, as Underwood pointed out, S. jamaicensis is minutely glandular-puberulous (minute one-celled glandular hairs) on veins and leaf tissue and lacks stellate or branched hairs on the ultimate veins, whereas S. underwoodianus has glabrous leaf tissue and dissected scales on veins and costae. Both S. underwoodianus and S. palmatus differ from S. bifidus and S. brevipubis in having more highly forking pinnae, 3–5- forked vs. 1–2(–3)-forked. See S. palmatus, the most closely related Mexican species, for further comparison.
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Distribution
Frequent at higher elevations, on wet banks along roads and forest margins, cloud forests, elfin forests, alder forests, pine forests, pine-oak forests; 1500–2700(–3050) m. Mexico; Guat, Hond, Salv.
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