4 Bower. — Studies in the Phytogeny of the Fili cates. VI. 
this Fern 1 widely from Cheiropleuria (p. 128), and does not establish any 
comparison between them. Similarly Christensen, in the systematic group- 
ing introductory to his ‘ Index Filicum ’, places Leptochilus tricuspis , C. Chr., 
with the Dipteridinae (p. 26), while Cheiropletiria is placed far away with 
the Platyceriinae (p. 53). Thus the more modern writers appear to agree in 
ignoring the comparison which Sir William Hooker established between 
Cheiropleuria and the Fern now before us. Though I had long known 
of the existence of this Fern, my attention was first definitely drawn to if by 
Dr. R. C. Davie. I then asked the Director of the Calcutta Garden to send 
home material. Through his kindness I have received from Mr. Cave 
of Darjeeling an ample supply of specimens, both dry and preserved, in 
formaline, upon which the following observations are based. My best 
thanks are due to the Director, and to Mr. Cave for the selection and 
preservation of the material. 
External Characters. 
Leptochilus tricuspis is a fine Fern, with upstanding fronds rising to 
a height of nearly three feet. They spring from a stout creeping rhizome 
rather over J inch in diameter, of rather fleshy character. It is densely 
covered while young by brown scales, which fall away from the older parts. 
From this the leaves arise roughly in alternate order, right and left ; but the 
sequence does not appear to be always strictly maintained. The leaf- 
stalk is stout, and naked when mature, excepting the last quarter of an inch 
at the base, where it enlarges into a mammillary swelling, which persists 
with a terminal scar after the old leaf itself separates by an almost smooth 
abscission. It is in fact a typically ‘ Eremobryoid ’ type, after the termino- 
logy of John Smith. 2 Frequently the rhizome may grow to a length of six 
inches or more without any branching. But occasionally lateral branches 
are formed, apparently without any near relation to a leaf ; their appearance 
suggests that they arise by some terminal branching, as in Dipteris , rather 
than as appendages to a leaf, as in Cheiropleuria . 3 
The leaves are strongly dimorphic, though Sir William Hooker 
mentions a specimen which ‘ has the upper half of two out of the three 
lobes contracted and soriferous, thus connecting this group with Hymeno- 
lepis ’. 4 Both sterile and fertile leaves have long smooth petioles, but the 
fertile are the taller. Both are ternate, with the terminal lobe the longest, 
and this is an almost constant character. But the specimen from India, 
in the hands of Dr. Davie, shows a rudimentary fourth lobe (Plate I, Fig. 1), 
reminiscent of a katadromic helicoid system, as in Matonia. The barren 
leaves are firm and naked, with the three entire lobes of coriaceous texture. 
Each has a well-marked midrib, the lateral venation being of the type 
2 Historia Filicum, p. 66. 
4 Syn. Fil., p. 422. 
1 Farnkrauter, p. 49. 
3 Seward : Phil. Trans., B, vol. 194, p. 494. 
