158 PERNS OF GREAT BRITAIN. 



The brown creeping stem of the Wood Horse-tail is 

 branched, and is tufted with fibrous roots. This plant 

 has two kinds of fronds ; they have both erect stems ; 

 and both, when fully grown, are surrounded by com- 

 pound branches, though these are fewer on the fertile 

 than on the barren stem. The fertile stems are at first 

 quite without branches, but these soon develop them- 

 selves, and are generally from six to eight in number. 

 The stem is from half-a-foot to two feet in height, of 

 a dull faded looking green colour, succulent, and having 

 about twelve slender ridges, with corresponding furrows. 

 It is not so rough nor so firm as in most of the species, 

 on account of the extreme minuteness of the flinty 

 particles in the cuticle. The margins of the sheaths 

 are cut into three or four lobes, and the sheaths are 

 large and loose; the lower half are pale green, and 

 the lobes of a bright brown colour, and they are marked 

 with the same number of ribs as the stem. The 

 whorled branches are slender, about two inches long, 

 curving downwards; and a marked feature of this 

 species is, that these branches have other branches 

 growing at their joints. These secondary branches are 

 from half-an-inch to an inch long. The cone, which is 

 matured in April, is long, somewhat tapering, and of 

 a pale brown colour, standing on a slender stalk longer 

 than itself. The scales are more than eighty in number, 

 and when ripened disperse a great number of pale 

 greenish-coloured spores. The cone dies away long 

 before the stem or branches have begun to wither, but it 

 is rarely seen, for this species does not often bear fruit. 



The barren stems, which are of a much less succulent 



