NIPHOROLUS. 61 



GENUS III. 



NIPHOBOLUS. Kaulfuss. 



A SMALL interesting family, whose name is adopted from the 

 fact that the fronds are covered with a somewhat white starry- 

 pubescence. Although, to the ordinary observer, the genus has 

 certainly no pretension to the name Niphobolus — covered with 

 snow, which would have applied better to a portion of the 

 species of Gijmnogramma or Nothochlcena, still, when examined 

 with a magnifying glass, the fronds are observed to be scattered 

 over with snow-like crystals; hence the name is a very appro- 

 priate one. 



We have no British representative of this family. 



The fronds are all simple, that is, they are not divided; the 

 veins, which are pinnate, are internal and almost invisible; 

 the venules are parallel, anastomosing transversely, and pro- 

 ducing from two to five irregular, excurrent, free vein lets, 

 which, at the apex, are soriferous. 



There are both barren and fertile fronds; the latter contracted, 

 and in some species much longer than the barren fronds. The 

 length of the frond varies from that of an inch to nearly two 

 feet, being attached to a creeping or caespitose caudex. In 

 habit this genus may be said to more closely resemble that of 

 the mosses, than the ordinary character of the Fern tribe. 

 The fronds are thick and fleshy. In order to observe the 

 venation it is requisite to remove the cellular tissue of the leaf. 



The sori are round, terminal, and eventually become confluent, 

 protruding through the stellated pubescence. 



The chief characters of distinction from other branches of 

 the PolypodiecB are the thick stellated pubescence, or scales, 

 which are found chiefly on the soriferous part of the frond; 

 and this is more especially to be noticed on account of the 

 fleshy thick frond preventing the venation being seen. 



