CHARACTERS OF TRIBES AND GENERA. 119 



rilust. Hook. Ml. Exot., t. 78 ; Hook. Gard. Ferns, t. 3 ; 

 Moore Ind. Fil., p. 15, A; J. Sm. Ferns, Brit, and 

 For., fig. 19 ; Hook. Syn. Fil., t. 8, fig. 60, cc.,dd.,ee. 



OBS. This genus is distinguished from Drymoglossum 

 by the fronds being uniform, and their contracted upper 

 portion bearing the sporangia, which become confluent, 

 and which led some authors to place it in the genus Acros- 

 tichum. 



Sp. H. spicata (Linn.) (v v.) ; H. platyrhynchos, J. Sm. ; 

 H. brachystachys, /. Sm. (H. spicata var. brachystachys, 

 Hook. Gard. Ferns) (v v.). 



H. spicata is found very generally throughout the tropics 

 of the Eastern Hemisphere, while H. platyrhynchos is as yet 

 only known as a native of Luzon. 



35. LEPTOCHILUS, Kaulf. (1824). 

 Acrostichum sp. auct. ; Hook. Sp. Fil. 



Surculum caespitose, or slender elongating. Fronds 

 6 to 18 inches long, of two forms ; the sterile simple, 

 lobed, or pinnatifid, smooth ; the fertile contracted, linear- 

 rachiforrn, its margins revolute and indusaeform. Primary 

 veins of sterile frond evident, straight or flexuose, venules 

 compouudly anastomosing. Receptacles elongated, compital. 

 Sorus linear, continuous, uniserial, on each side of the 

 costa, ultimately confluent, destitute of scales. 



Type. Acrostichum a,cillare, Cav. 



Illust. Hook. Gard. Ferns, t. 6 ; J. Sm. Ferns, Brit, and 

 For., fig. 20. 



OBS. I have already stated that on account of the 

 contraction of the fronds in the preceding genera, the 

 individuality of the normal punctiform receptacle is des- 

 troyed, and they become so connected as to form a continuous 



