152 ENGLISH BOTANY. 



the fertile stems appear, and last till October or November ; perhaps 

 if the female spikes are started into growth in the summer or autumn 

 they develop branches. 



According to Milde, the sterile stem, terminated by a spike, is the 

 E. eburneum of Schreber. 



Great Horsetail. 



SPECIES II.— E QUI SET UM ARVENSE. Linn. 



Plate 1889. 

 Babenh. Crypt. Vase. Exsicc. Nos. 46, 47, and 48. 



Stems of two kinds, perishing in autumn. Sterile stem rather 

 slender, with 6 to 19 furrows, slightly rough, especially in the upper 

 part, green. Sheaths shortly cylindrical, very slightly widened 

 upwards, pale green ; teeth 6 to 19, free or some of them united in 

 pairs or threes, triangular-subulate acute, concolorous or edged 

 with pale brown, with very narrow light brown scarious margins. 

 Branches numerous, rarely few, ascending or slightly drooping in 

 luxuriant specimens, usually 4-quetrous, with the ridges not grooved 

 and separated by very deep furrows and the angles not grooved, solid, 

 unbranched or rarely with a few branchlets, their lowest internode 

 exceeding the teeth of the stem-sheath between which it is pro- 

 duced ; sheath enclosing the base of the first internode of the branch 

 pale brown or olive, dim, furnished with short roundish-ovate teeth 

 with narrow pale scarious margins ; sheaths at the apex of the first 

 and succeeding internodes of the branches terminated by as many 

 subulate teeth as there are angles on the branch. Fertile stem more 

 or less elongated, moderately stout, succulent, whitish or pale brown, 

 smooth. Sheaths rather distant, tubular-funnel-shaped,, sulcate, 

 whitish at the base, brown towards the apex ; teeth 8 to 14, most 

 of them often united into groups of 2 or 3, dark brown, triangular- 

 subulate, often somewhat connivent. Spike cylindrical-oblong, 

 obtuse, pale brown. Rarely fertile stems are produced along with or 

 after the sterile stems, which are much firmer and greener than the 

 ordinary state, with pale green sheaths, and these generally ultimately 

 produce whorls of branches like those of the sterile stem, but often 

 with the first internode of the branch not exceeding the sheath below 

 which it is placed. 



By roadsides and in waste places, and in cultivated ground, very 

 common, and generally distributed throughout the country. 



England, Scotland, Ireland. Perennial. Spring. 



