XV 
times distinct; text, subcoriaceous. both surfaces an opaque 
greyish green ; veins free, subflabellate ; sori copious. 
D.(avalha) (Leucos.) choerophylla, Wall. rhiz. wide- 
creeping, clothed with broad obtuse adpressed scales ; st. 
4 — 6 in. 1., naked ;fr. 9 — 15 in. 1., 1 in. br. lane. delt. 3 
or 4 pinnatifid; lowest pinnl.fiules) 1 — 2 in. 1., 1 in. br. 
cut down to narrowly winged rachis into deeply pinnati- 
fid segm. (ents), ult. lobes narrow and acute in fertile, 
rather broader in barren, fr. ; text, thinly herb., rather 
flaccid ; sori copious, at base of teeth of segm., which they 
about equal in breadth, 
21. The fructification at back of frond consists of 
groups of capsules ( sporangia ) covered ( indusiate ) or not 
( non-indusiate ) by a membranous covering called the indu- 
sium, or more generally, involucre. 
This involucre in shape is globose, (Cyathea, Dick- 
sonia)reniform(Nephrodium, Oleandra) tubular (Davallia, 
Tricho manes) of same shape as sorus (Asplenium) ; it is 
lipped (Trichomanes, Dicksonia) or entire as generally ; is 
in texture soft membranous (Woodsia) subcoriaceous 
(Woodwardia) coriaceous (Sphseropteris), formed of chang- 
ed margin of frond (Pteridieae) ; arising from beneath sorus 
and therefore inferior, (Cyathea, Woodsia) from above 
and superior, (Aspidium). Its character is best deter- 
mined by the aid of young fronds, which should be ob- 
served in different stages of fructification. Many ferns 
shed their involucre earlv. it is evanescent, or deciduous ; 
and since this envelope determines the shape of sorus and 
