Class XXIV. Order I. 259 



branches radiately forked ; spikes nearly sessile, 

 cylindrical. 



The shoots of this species are erect, ascending at base, cov- 

 ered with small, imbricated, lanceolate leaves. Branches al- 

 ternate, dividing by successive forks, the branchlets diverging 

 like rays from a centre. Leaves in six rows, those of the later- 

 al rows longest. Spikes terminal, solitary, sessile, cylindrical. 

 Like others of the genus, they give out, when ripe, a great 

 quantity of minute seeds, resembling a fine, yellow powder, and 

 very inflammable. Woods. Perennial. 



294. EQUISETUM. 



EquisETUM HYEMALE. L. Rough Horsetail. Scouring 



Rush. 



Stem naked, very rough, mostly branched at 

 base ; sheaths whitish, black at the base and sum- 

 mit. 



Found in moist woods at Lynn, and elsewhere. Stems 

 erect, without branches, except at base, hollow, naked, furrow- 

 ed, the ridges rough with minute teeth, which arc hardly visi- 

 ble without a glass. The joints of the stem are surrounded 

 with short sheaths, coloured with black and white rings, and 

 toothed at the top. The fruit grows in an ovate, terminal 

 ament) composed of peltate, six sided scales, bearing the seeds 

 inside. 



The whole surface of the stem is rough, like a file, and is 

 used in scouring and polishing metallic vessels. Its cuticle, 

 according to Mr. Davy, contains a considerable portion of sili- 

 ceous earth. Perennial. 



EquisETUM ARVENSE. L. Field Horsetail. 



Fertile scape naked ; barren frond with whoii- 

 ed branches, decumbent. Z. 



