I0'2 " ENGLISH BOTANY. 



8 to 34, deltoid-triangular or triangular, acuminated into long 

 setaceous-subulate flexuous or straight points, which are wholly 

 scarious, pitchy-black, with narrow paler margins, and are often 

 caducous except on the terminal sheaths, in which case by their 

 fall they leave the sheaths truncate and crenate — these crenatures 

 corresponding with the bases of the teeth ; more rarely the points of 

 the teeth of all or of some of the sheaths are persistent. Branches 

 very rarely produced, and then solitary, resembling the stem in 

 miniature, with the first internode much shorter than the stem- sheath 

 below which it is produced ; sheath enclosing the first internode of the 

 branch pitchy-black, shining, oblique ; sheaths at the apex of the first 

 and succeeding internodes of the branch terminated by triangular 

 teeth with deciduous subulate scarious points. Spikes oval- or roundish- 

 or oblong-ovoid, acuminated and mucronate or apiculate, pitchy-black 

 or pitchy-brown, its base embraced by the teeth of the uppermost 

 stem-sheath. 



Subspecies I.— Equisetum eu-hyemale. 



Plate 1894. 



Eabenh. Crypt. Vase. Europ. Exsicc. No. 49. 



E. hyemale, Newman, Phytol. 1854, p. 19. 



E. hyemale, var. genuinum, A. Braun ; Milde, Fil. Europ. p. 243. 



Stems all similar, sub-evergreen, mostly solitary from each node or 

 extremity of branch of the rootstock, rather stout, with a central 

 hollow of about two-thirds its diameter with 15 to 34 rather shallow 

 furrows separated by subobtuse ridges, which are not furrowed on the 

 back, and are rough with small prominent tubercles arranged in one 

 stripe on each ridge, dull dark green. Sheaths cylindrical, closely 

 applied to the stem, pale green, at first concolorous, then with a 

 black band at the apex and afterwards another at the base, after- 

 wards wholly black, ultimately white with a black band at the 

 base and a narrower one at the apex, the lower ones permanently 

 black ; each of the portions of the sheath which corresponds to 

 one of the teeth with a narrow shallow furrow down the centre, 

 and another similar shallow furrow on each side between the 

 central furrow and the great furrow which extends (between the 

 teeth) from the apex to the base of the sheath ; teeth 15 to 34, 

 deltoid-triangular, acuminated into long setaceous, subulate flexuous 

 or crisped roughish points, which are wholly scarious, pitchy-black 

 with narrow paler margins, and are caducous except on the terminal 



