SHOT. vm. MAIDENHAIR FERN. 3 5 9 



edges of the leaf, which are folded over with them, and 

 thus serve as an indusium. Adiantum has a free vena- 

 tion, but Hewardia, a related genus, has a reticulated 

 venation. The Adiantiese have linear, oblong or lunate 

 sori, seated on the margin of the leaf. Of the seventy 

 species of Adiantum, only A. pedatum and A. Capillus- 

 Veneris, the first American, the latter British, are in- 

 habitants of a cold climate. The A. Capillus-Veneris, 

 which is universally distributed in warm latitudes, is 

 believed to have migrated in ancient times to the mild and 

 damp south-western counties of England and Ireland. 



The Adiantum Capillus-Yeneris, or Maiden's Hair, 

 has a slender, black, scaly, creeping, and branching 

 rhizome, from the extremities of which spring lax tufts 

 of fronds growing from a few inches to a foot high. 

 The stems with their alternate branches and branch- 

 lets are slender, hair-like, and of a blackish purple 

 tint. The capillary branchlets bear at their extremities 

 thin, bright, but glaucous green, wedge-shaped leaves, 

 serrated at their edges. The fibro-vascular bundles 

 which traverse the 

 stems and branches, 

 on reaching the leaves, 

 spread into a palmate 

 venation, which termi- 

 nates at the margin 

 in bifurcations ; and 

 upon these, in the ^ 67- Adiantnm CapillU8 _ Venerig . 



fertile leaves, roundish 



sori are placed, and covered by the transverse oblong 

 folds of the edge of the leaf, as in fig. 67. These deli- 

 cately graceful ferns flourish almost exclusively in damp 

 shady crevices of rocks under the spray of cascades, and 

 still more luxuriantly in deep tropical forests, where the 

 air is loaded with warm vapour. 



The Acrostichese are among the most remarkable of 



