206 
* 
Trispe ]—CvyaTHe® 
Tree-ferns.—Sori dorsal], round ; sporan- 
gia stalked or sessile on an elevated 
receptacle ; indusium inferior, in the torm 
of a scale beneath the sorus, or completely 
enveloping the sorus, ultimately bursting 
at the top and forming acup. It is absent 
in Alsophila. 
Caudex arborescent ; indusium globose, 
ultimately rupturing at the apex so as to 
form a cup holding the sorus. 
Genus II.—Cyathea 
Caudex arborescent ; sori .round, naked. 
(Distinguished from Cyathea by the 
absence of indusium). 
Genus IIJ.—Alsophila R. Br, 
Tribe [].—DicKxsonin#& 
Sori round, at the back or apex of a 
vein ; indusium inferior, leathery, mounted 
on a stalk, covering the whole sorus and 
bursting irregularly, or cup-shaped, entire 
or two-lipped. Veins free or anastomosing. 
Sori round, arising from the back ofa 
vein or veinlet ; indusium inferior, globose, 
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