224 CHARACTERS OF TRIBES AND GENERA. 



or pinnate ; venules free. Sori punctiform, terminal. 

 Indusium 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. 



OBS. This genus was first characterised by me in Dr. 

 Hooker's " Flora of New Zealand," the type being Polypo- 

 dium tenellum Forster. I there stated that although no 

 indusium had been detected on New Zealand specimens I 

 nevertheless associated with it the Nephrodium oUiteratum 

 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. olliterata gives them some claim to rank in Ery- 

 molrya, and in A. allo-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 heteromorpJium, 

 a Fern of peculiar habit of growth, having slender dichoto- 

 mous or unequally branching fronds, each branch being 

 pinnate, the pinnae 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 Otenopteris and Hy- 

 menop Jiy I lum . 



