THAI FOREST BULLETIN (BOTANY) 36
rachis, remaining pinnules decurrent, eventually coadnate, pinna and pinnules acuminate; remaining pinnae to 10 cm apart, much narrower, pinnatifid, to 29 x 6 cm, lower pinnae on short stalks, gradually becoming sessile, eventually coadnate; veins forming costular areoles, otherwise free, running almost to margin, usually branched; costa and costules very densely covered in articulated orange hairs above, same but less dense beneath. Sori in 1–3 indistinct rows either side of costules, on veins, only occasionaly terminal, exindusiate, 0.6–0.9 mm wide. Spores ellipsoidal, rugose.
Distribution.— Only known from the type from Khlong Phanom National Park in Surat Thani.
Ecology.— Collected from a pocket of thin soil on a limestone cliff; altitude ca 100 m
IUCN Conservation StatusAssessement.— Least Concern (LC).Although the species is currently only known from the type specimen it was collected on karst limestone in Khlong Phanom National Park, a habitat that is extensive and well protected in this Park and in the contiguous and even larger Khao Sok National Park.
Notes.— Khlong Phanom National Park in Surat Thani province is proving to be one of the most interesting sites in Peninsular Thailand due to its high number of endemics. This new species of Tectaria grows close to the site of the recently described Adiantum phanomensis S.Linds. & D.J.Middleton (Lindsay & Middleton, 2004). It is characterised by the many long costular areoles and the lack of indusia.
Images of the isotype (atA) are available on the Harvard University Herbaria website (www.huh.harvard.edu).
We would like to thank Rachun Pooma, Chandee Hemrat & Suwat Suwanachat for their help and company in the field. The National Geographic Society is gratefully acknowledged for funding the expedition. The reviewers are thanked for their valuable comments.
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