distinguished by the sori being terminal and marginal, as 
also by the frondg before evolution being densely crini- 
ferous, the hairs being long and articulated, thus differing 
from Cyathea, which instead of hairs, are furnished with 
squamæ. 
Sp. D. arborescens, L'Herit. (v v.); D. chrysotricha, 
Moore. (Balantium, Hassk.); D. squarrosa, Sw. (v ei: 
D. fibrosa, Colenso; D. Sellowiana, Hook (v v.); D. 
Berteroana, Hook; D. lanata, Col.; D. Youngii, C. Moore 
(v v.). 
137.—Crortum, Kaulf. (1824.) 
Dicksonia, sect. Cibotium, Hook., Sp. Fil. 
Vernation fasciculate, decumbent or erect, and arbores- 
cent, densely criniferous. Fronds bipinnate, 5 to 15 feet 
long; pinnules bipinnatifid, generally glaucous beneath. 
Veins simple, forked or pinnate, venules free. Receptacles 
punctiform, terminal. Indusium bivalved, horny, the outer 
valve (accessary indusium) concave, cucullate, adnate to the 
margin; the inner (special indusium) smaller, and con- 
niving with the outer, forming an unequal bivalved box- 
. like cyst. 
Type. Dicksonia glauca, Smith. 
Illust. Hook. and Bauer, Gen. Fil, t. 25; Moore, Ind. 
Fil., p. 78 B. ; J. Sm., Ferns, Brit. and For., fig. 128 ; 
Hook. Syn. Fil., t. 2, fig. 13, a. b. 
Oss.— This is a very distinctly marked genus, readily 
distinguished from Dicksonia and its allies by the outer ` 
valve being special, and formed on the reflexed margin 
of the frond as in Dicksonia, but superficially seated on 
the edge of the segments, rising from the outer base of the 
‘receptacle, and conniving with the interior special indu- 
CHARACTERS OF TRIBES AND GENERA. ‘ee 
