Tectaria phanomensis S.Linds.
Tectaria phanomensis S.Linds, Thai For. Bull. (Bot.) 36: 49. 2008.
Fern growing in limestone crevice with ascending rhizome; rhizome densely covered in scales. Scales yellow-brown to dark brown, widest at base, to 15 x 1.25 mm, thin, brittle, crisped, composed of long cells, with long slender twisted tip, margins entire. Stipes 40–48.5 cm long, 4 mm diameter, brown beneath, green above, scales dense near base or in lower half, becoming more scatter above, sometimes even onto rachis. Laminae triangular, to 63 x 65 cm, with c. 8 pairs of free pinnae and terminal section with gradually reducing pinnae decurrent into neighbour; basal pinna largest, stalked, 34–36 x 20–21 cm, strongly asymmetrical, basiscopic pinnules enlarged, with first 4–5 basiscopic pinnules much longer than corresponding acroscopic pinnules, first acroscopic pinnule sessile, 1.5–2 cm from rachis, first basiscopic pinnule with short stalk or not, 2.1–3.3 cm from 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 costal 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 occasionally terminal, exindusiate, 0.6–0.9 mm wide. Spores ellipsoidal, rugose .
Distribution in Thailand
PENINSULAR: Surat Thani.
Endemic to Thailand. Only known from Khlong Phanom National Park.
In thin soil on a limestone cliff; altitude c. 100 m.
Proposed IUCN Conservation Assessment
Least Concern (LC). The species is currently only known karst limestone in Khlong Phanom National Park, but this is a habitat that is extensive and well protected in this Park and in the contiguous and even larger Khao Sok National Park.
Voucher specimens - Thailand
Middleton et al. 4362 & 5552, Surat Thani, Khlong Phanom National Park (E).
Upper surface of lamina showing hairy costae
Upper surface of lamina
Lower surface of lamina
Lower surface of lamina with young sori
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