514 MR. C. B. CLARKE ON THE FERNS OF NORTHERN INDIA. 
Pheg. & Asp. 86. A. Thelypteris, Benth. Fl. Hongk. 445, not of Desv. A. angus- 
tifrons, Miq. in Ann. Mus. Lugd. Bat. iii. 178. Lastrea gracilescens, Hook. Kew 
Journ. Bot. ix. 338; Bedd. Ferns Brit. Ind. t. 253. . L. Jlaccida, Bedd. Ferns South. 
Ind. t. 250. ZL. immersa, Bedd. Ferns Brit. Ind. t. 252 (only very partially NepAro- 
dium immersum, Hook.). 
Nepaul and Sikkim, alt. 6000-8000 feet; not common, C. B. Clarke. Assam; Griffith. 
Khasia; alt. 4000 feet, plentiful.—Distrib. South India and Ceylon, Java, China, Japan. 
The above description applies to all the Kew N. gracilescens; Griffith's Assam speci- 
mens, referred to Nephrodium immersum in Hook. Sp. Fil. iv. 112, are identically the 
same.. Beddome’s figure (Ferns Brit. Ind. t. 252) represents Griffith's specimens very 
well; the Malay true N. àmmersum has very long and narrow segments; the involucres 
and the texture of the frond differ materially from N. gracilescens.—N. Thelypteris has 
a more creeping rhizome, a more glabrous main rhachis, the veins in the segments 
generally forked. W. flaccidum, Hook., has the sinus between the segments of the pinnze 
obtuse. W. puberulum, Baker, would come between N. gracilescens and .N. flaccidum 
if there was any space between the two; Col. Beddome has in litt. expressed his opinion 
that there is none—The Kew bundle of N. gracilescensis very homogeneous ; the follow- 
ing varieties of my own collection are very difficult :— 
Var. 1. decipiens (Pl. LXV. fig. 2). Frond shorter, deltoid-lanceolate; veins in the seg- 
ments frequently branched, the sori subterminal on the upper branch. ( 
Darjeeling, alt. 7500 feet, C. B. Clarke, No. 12,421.  Dingling in Khasia, alt. 5000 
feet, C. B. Clarke, No. 18,460 n.—This seems to me hardly a variety of N. gracilescens, 
while Mr. Baker objects to its being any way connected with it. In the extreme form 
the segments of the pinne are serrated, the veins becoming subpinnate in each 
serration. 
Var. 2. hirsutipes (Pl. LXVII. fig. 1). Stipe hirsute at its foot; frond elongate, stouter 
in texture than N. gracilescens type; sori large, in two rows close to the midrib of 
the segments; involucres large, pubescent, very persistent. 
Khasia and Jaintea, alt. 4000-5000 feet, frequent.—Very constant in all its characters, 
as in the coarse hair at the foot of the stipe. | 
Var. 3. didymochlenoides (Pl. LX VII. fig. 2). Stipe subglabrous, shining chestnut ; 
sori large, covering the segments entirely ; involucres large, persistent, elliptic. 
Khasia; Sohra Coalhill, alt. 4300. feet, C. B. Clarke.—The extreme form is more 
didymochlznoid in the involucre than is much of Didymochlena itself; but this variety 
is connected by various intermediate forms with the typical N. gracilescens. 
4. N. our, C. B. Clarke. Tufted; stipe long, pubescent, without- auricles; frond 
narrowly oblong-lanceolate ; lowest pinne little shorter, often deflexed ; main 
 rhachis and rhachis of the pinne above pilose; pinnæ cut halfway down or nearly 
the whole way down to the midrib ; lobes oblong, obtuse, sometimes narrowest s 
_ upwards, often oblique to the midrib, two lowest veins often terminating close p. 
