a D24 CHARACTERS OF TRIBES AND GENERA. 
or pinnate; venules free. Sori punctiform, terminal. 
Indusiwm reniform or absent. 
Type. Polypodium tenellum, Forst. 
Illust. Schk. Fil., t. 16 ; Hook. Fil. Exot., t. 89; J. Sm., 
Ferns, Brit. and For., fig. 78. 
Oss.—This genus was first characterised by me in Dr, 
Hooker’s “ Flora of New Zealand,” the type being Polypo- 
dium tenellum Forster. T there stated that although no 
indusium had been detected on New Zealand specimens I 
nevertheless associated with it the Nephrodiwm obliteratum 
of Brown, which has a very small fugacious indusium, and 
although Aspidium albo-punctatum of Bory, has a well. 
defined reniform indusium, its other points of character 
seem to indicate its affinity with A. tenella, The apparent 
articulation at or near the base of the stipes of A. tenella 
and A, obliterata gives them some claim to rank in Ery- 
mobrya, and in A, albo-punctata the apparent joint is often 
2 to 3 inches above the base of the stipes. These charac- 
ters seem to indicate a natural relationship of these species 
to one another, to which I add Polypodium heteromorphum, 
a Fern of peculiar habit of growth, having slender dichoto- 
mous or unequally branching fronds, each branch being 
pinnate, the pinnse numerous, oblong, entire or variously 
lobed, not exceeding half an inch in length, their bases 
articulate with the rachis, and having white dots on the 
upper surface, which, with the sori being terminal and 
naked, leads me to consider these points sufficient to 
warrant its being placed in the present genus. It is a 
native of Mexico, New Grenada, and other parts of tropical 
. America, growing round the base of trunks of trees, on 
moist rocks, and even in caves, its slender fronds being 
pendulous, similar to some species of Ctenopteris and Hy- 
menophyllum, 
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