Pteris subiriana Piu Das sp. nov. (Fig. 1A–G, 3A–B).

Type:— INDIA. Maharashtra: Mahabaleshwar, 1219 m, September 1918. L.J. Sedgwick & T.R.D.Bell 4797 (holotype, CAL!, Acc No. 8312).

Diagnosis:— Pteris subiriana (Fig. 1A–H, 3A–B) is similar to P. blumeana (Fig.2A–E, 3C–D) in gross morphology and growth habit, but the former has a sub-erect rhizome (Fig. 1E), bicolorous rhizome scales (Fig. 1D, D1, D 2) and distinct arcuate foldor band near to the leasurae in proximal surface of the spores (Fig. 3A). In contrast P. blumeana has erect rhizome (Fig. 2A), concolorous rhizome scales (Fig. 2C, C 1, C 2) and tuberculate to fused verrucate ornamentation in proximal surface of the spores (Fig. 3C, D). The stipe is glossy in P. subiriana, but matt in P. blumeana.

Description:—Plants terrestrial (Fig. 1A), 61–104 cm tall. Rhizomes short, sub-erect, 2–3 cm long, 0.5–1.5 cm in diameter (Fig. 1E). Stipe as long as the lamina, stout, scaly at the base, smooth, grooved above, 35–60 cm long, 0.4–0.6 cm in diameter, stramineous; rhizome scales same as stipe-scales, narrowly lanceolate, bicolorous, base cordate, margin ciliate, the central part composed of thick walled dark brown cells, margin pale brown. Laminae 32–40 long, 18–23 cm wide, bipinnatifid throughout except basally, imparipinnate apically, lowest pinnae pinnate-bipinnatifid with one or sometimes two developed basiscopic basal pinnules; pinnae 5–12 pairs, alternate to opposite, 9–16 cm long, 1.5–3 cm wide, sessile, basal pairs shortly stalked, lanceolate, acuminate (Fig. 1A); costae bearing a short adaxial spine at the base of each segment midrib, spine more than 1 mm (Fig. 1B); pinna-lobes (ultimate lobes) 20–30 pairs, 1.1–1.5 cm long, 2–3 mm wide, oblong to linear, narrower, apices rounded, entire, widely joined at their bases, base of sinus reaching to about 2 mm from the costa, without a sinus-tooth, lowest pair of veinlets between pinna-lobes and beneath the sinus free and curving evenly up to just above the base of the sinus, 8–14 pairs of veinlets above (Fig. 1C). White or pinkish setae above the adaxial surface of the midribs, setae narrow, 1 mm long, triangular to lanceolate, pointed (Fig. 1B). Sori sub-marginal, elongated, extending nearly towards the sinus and not reaching of the pinna-lobe; pseudoindusium hyaline, 87.5 × 12.5 μm, slightly elongated to irregular in shape (Fig. 1F, G); sporangial stalk very long, biseriate; capsule globose, 550 μm long, 200 μm wide; annulus 18-celled (Fig. 1H); paraphyses pale, long, septate, 200 μm long, 10 μm wide. Spores golden brown in colour, trilete, triangular in polar view, margin continuous, corner rounded, size 40–42 μm, on proximal surface distinct arcuate fold or band present near to the leasurae and outside leasurae slightly tuberculate (Fig. 3A), distal surface rugate, formed inside deltoid base, and smooth, apparently perispore is thick and single-layered (Fig. 3B).

Sori ripening:—October–December.

Habitat:—Grows near waterfalls.

Distribution:— INDIA: Kerala, Maharashtra and Tamil Nadu.

Additional specimens/ Paratypes: INDIA: Kerala: s. loc. s.d. N. C. Nair s.n. Acc No. 1820, 1819, 1818, 1817, 1814 (CAL); Karimala, 2895.6 m, 27 April 1976. B. K. Nayar & S. Pankaj 7373 (CALI); Maharashtra: Mahabaleshwar, 1219 m, November 1918, L.J. Sedgwick & T.R.D. Bell 4797 (CAL); Bombay Pt. road near holiday camp., 11 October 1918, S.D. Mahajan 27128 (BSI); Mahabaleshwar, 24 February 1956, S.D. Mahajan s.n. (BSI); Mahabaleshwar, 28 November 2011, V.K. Rawat 199705 (BSI); s.loc., 30 November 2011, V.K. Rawat 199730 (BSI); Mahabaleshwar, 3 December 2011, V.K. Rawat 199760B (BSI); Tilari dam, 732.73 m, 17 September 2013, A. Benniamin 195227, 195229 (BSI); Ozarde waterfalls, 21 September 2013, A. Benniamin 195271 (BSI); Lingmala waterfalls, 24 September 2013, A. Benniamin 195309, 195316, 195299 (BSI); Koyna Dt., Near the Ozarde falls area, 17°40’ N, 73’ 75° E, 14.September 2014, Piu Das 66657, 66644, 66652 (CAL); Tamil Nadu: Travancore, 146.3 m, 5 May 1883, H.C. Levinge s.n. Acc No. 8253 (CAL).

Etymology: This species is named after Dr. Subir Bandyopadhyay, Scientist in the Botanical Survey of India, and Kolkata for his invaluable help and encouragement to the first author during her study.