125 WAYSIDE AND WOODLAND BLOSSOMS 



The genus Nephrodium (named from nephros, the kidneys, in allusion to the 

 involucre) contains half-a-dozen other British species, of which the most frequent is 

 the Broad Buckler Fern (N. sflinnZasum), with arching fronds, broad at the base, the 

 stipes sparingly clothed with dark-brown scales. Pinnules toothed, the teeth ending 

 in long soft points. Damp woods. 



Mountain fern (N. oreopteris), with habit of Male fern, but stiffer, and of a 

 yellow-green hue. Spore-heaps near the margins of the pinnae. High hills and 

 mountain pastures. 



Field Horsetail (Equisetum arvense). 



The Horsetails are a small group of flowerless plants, quite 

 distinct from the ferns, though there are certain points in 

 which some resemblance may be traced. We have eight 

 British species out of twenty-five that are known to inhabit the 

 earth. The most widely distributed of these is the Field 

 Horsetail (E. ai"vense\ which farmers regard as a pest. In 

 common with the whole tribe it has a creeping underground 

 rootstock, from which more or less erect jointed stems arise. 

 If we break off one of these joints at its natural articulation 

 we shall observe that the ends are solid, and that the upper 

 extremity is crowned by a sheath ending in long pointed teeth, 

 into which the lower end of the next joint fitted. This leaf- 

 sheath, as it is called, is composed of a number of aborted 

 leaves the only vestiges of leaves the plant possesses. Just 

 below the leaf-sheath a whorl of jointed branches is given off, 

 each constructed in a manner similar to the upright stem. If 

 now we cut our main joint across its middle with a sharp 

 knife we shall find that it is tubular, a central cavity occupying 

 about one-third of its diameter. Between this cavity and the 

 exterior wall is a series of small tubes, somewhat egg-shaped 

 in outline, the smaller end towards the central cavity ; 

 alternating with these and nearer the centre are a number of 

 smaller circular tubes. This section should always be made 

 when in doubt as to the species, for the shape and arrange- 

 ment of these cavities differs in each, as do the external 



