ONE-SIDED (OR WILSON'S) FILM FERN. 



Hymenopfyllum unilaterale. WILIDENOW. 



In Hymenopliyllum unilaterale the pinnae are what 

 is called decurrent in the upper part that is to say, 

 they are prolonged beyond their points of insertion, as 

 if running downwards, so that the fronds appear to be 

 one-sided, or unilateral. The name of One-Sided 

 might therefore be employed to designate it just as 

 well as if not better than the cognomen of its dis- 

 coverer. Like H. Tunbridgense, it grows from nume- 

 rous slender thready stems, into dense tufts, from 

 which spring a crowded mass of half-drooping brown, 

 green, or olive-coloured, semi-transparent fronds, 

 averaging from three to four inches in height. The 

 fronds are lanceolate and pinnate, the rachis is usually 

 somewhat curved, the piling are one-sided, convex 



