288 



F I L I C E S. 



Scale from the base of the receptacle. 1 g. Hairs from the receptacle. 

 1 h, h, h. Sporangia. 1 *. Sporules. — The dissections more or less 

 magnified. 



7. Alsophila Tahitensis, Sp. Nov. (Tab. 40.) 



A.frondibus bipinnatis ; pinnulis parvis sessilibus glabris oblongo-lan- 

 ceolatis profunde pinnatifidis, segmentis oblongis obtusis crenulatis ; 

 rhachi comrnuni flexuosa partialibusque supra rufo-tomentosis ; costa 

 subtus bullato-squamosa ; venis simplicibus vel furcatis; soris costce 

 proximis basi indusio semicalyciformi rnembranaceo lacero intus sti- 

 patis; receptaculo subgloboso; pills inter sporangia nullis. 



Hab. Tahiti, Society Islands. 



Fronds bipinnate, apparently unarmed, having a rusty appearance ; 



the divisions small and crowded. Pinnules sessile, smooth, usually 



from one to li inches long and 3 to 4 lines broad, oblong -lanceolate, 



pinnatifid almost to the rhachis. Segments scarcely 2 lines long and 



not quite a line broad, oblong, obtuse, crenulate. Primary rhachis 



flexuose, shrinking in drying, and, together with the secondary, rufous- 



tomentose above; the costa beneath furnished with lacerated, rusty, 



bullate scales. Veins thick, those nearest the base of the segments 



only are forked. Sori copious, crowded, seated near the costa, 



on the veins below the forkings, on a subglobose receptacle, having at 



its base on the inner side a membranaceous, semicalyciform indusium, 



the margin of which is lacerated ; in a recent state it nearly covers 



the sorus. 



We unfortunately possess only the summit of a frond of this 

 very interesting species, whose calyciform indusium points to its 

 affinity with Hemitelia, R. Brown; but with which its habit and 

 venation do not at all agree. 



Plate 40. — Fig. 2. Portion of a frond, of the natural size. 2 a. 

 Smaller portion of a frond, as seen from beneath. 2 b. Scale from 

 under side of the costa. 2 c. Indusium. 2 d. Vertical section of a sorus. 

 2 e, e. Sporangia. — The dissections all more or less magnified. 



