Microlepia kerrii S.J. Moore, 2017

Wang, Jenn-Che, Chang, Yi-Han, Chiou, Wen-Liang & Liu, Ho-Yih, 2017, Two new species of Microlepia (Dennstaedtiaceae, Polypodiopsida) from Thailand, Phytotaxa 324 (2), pp. 193-197 : 193-195

Microlepia kerrii S.J. Moore , sp. nov. ( Fig. 1)

Type: — THAILAND. Phang Nga (or Phangnga): Khao Bangto, 23 February 1929, A. F. G. Kerr 17207 (holotype K!, isotypes ABD!, K!).

Plants 35–45 cm high. Rhizomes long–creeping, 3.5–4 mm in diameter, densely covered with hairs; hairs setose, light brown, 2–3.5 mm long, 6–12 cells, usually remaining on old rhizomes. Stipes 1–3 cm apart, 15–20 cm long, stramineous to darker brown, shallowly grooved on adaxial surface, densely covered with hairs like those on rhizomes but shorter. Laminae 1-pinnate-pinnatifid at base, 1-pinnate in distal part, oblong-lanceolate in outline, 25–35 cm long and 14–20 cm wide, gradually narrowing upwards but somewhat abruptly reduced near apex, usually acute or acuminate at apex, truncate or widely obtuse at base; rachises like distal parts of stipes, distinctly grooved on adaxial surface and densely hairy throughout, hairs shorter than those on rhizomes, light brown and 1.3–2.5 mm long; pinnae 12–18 pairs, distal and central pinnae close and simple, proximal pinnae remote and lobed to pinnatifid, short-stalked, linear, straight or sometimes falcate, gradually narrowing towards apex, acuminate at apex, widely cuneate or sometimes slightly cordate at base, with a distinct oblong-elliptic auricle at acroscopic base (sometimes also at basiscopic base), dentate at margins, herbaceous, deep green on adaxial surface, lighter on abaxial surface; costae distinct, slightly grooved on adaxial surface, raised on abaxial surface, hairy on both surfaces; veins in ultimate lobes pinnate, veinlets simple or once forked (rarely twice), glabrous or slightly hairy on both surfaces. Sori terminal on veinlets, submarginal; indusia pouch-like, 0.7–1 mm wide, glabrous.

Distribution and habitat: —Known only from two localities in Thailand, where it is terrestrial in shaded, evergreen mountain forests at 700–1200 m elev.

Etymology: —This new species is dedicated to Arthur Francis G. Kerr (1877-1934), who was the collector of the type specimens.

Additional specimen examined (paratype): — THAILAND. Nakhon Si Thammarat (or Nakhon Srithamathat): Khao Luang, 24 August 1995, K. Larsen 45920 (NY!, AAU!).

Notes: — Microlepia kerrii is similar to M. hookeriana (Wall. ex Hook. 1845: 172) C. Presl (1851: 455) , but M. kerrii has a terminal pinna that is lobed or pinnatifid at its base and basal pinnae that are deeply pinnatifid, whereas M. hookeriana has an undivided terminal pinna and basal pinnae. It is also similar to M. marginata ( Panzer 1786: 199) C. Chr. (1905: 212) and M. calvescens (Wall. ex Hook. 1845: 172) C. Presl (1851: 455) , but differs from the former in the lamina having a more-or-less distinct and caudate terminal pinna (vs. lamina apex gradually shortened, pinnatifid, without a terminal pinna), hairs on rachises 1.3–2.5 mm (vs. 0.5–1 mm), the basal lobes of pinnae in the proximal half of the lamina being usually free (vs. margins of all the pinnae lobate, never having free lobes), and indusia glabrous (vs. hairy); from the latter in hairs on rachises 1.3–2.5 mm (vs. 0.3–0.7 mm), and the basal lobes of pinnae in the proximal half of the lamina being usually free (vs. at most deeply pinnatifid but adnate along the costa). Microlepia kerrii also resembles M. thailandensis , the new species described below; their differences are discussed in detail under M. thailandensis .