APRIL. 119 
‘species make their appearance at this time, and should be 
sought for with care. 
EQuisETUM ARVENSE. (Plate VI. Fig. 24.) Corn Horse- 
tail. The fertile stems about eight imches high, appear 
before the sterile, which are from one to two feet high. The 
former are erect, destitute of branches, their sheaths distant 
and deeply toothed. ‘The sterile have undivided, roughish, 
ascending branches, though rather drooping at the base. 
Found in fields and meadows, common. 
EQUISETUM FLUVIATILE. Great water Horse-tail. Sterile 
stems with very numerous undivided, angular, roughish 
branches. Fertile stems unbranched, their sheaths crowded, 
deeply toothed. Fertile stem from one to two feet, and 
sterile, from two to four feet high. Grows at the edges of 
rivers and lakes. 
Haquisetum syLvaticuM. Wood Horse-tail. Sterile and 
fertile stems with compound whorled branches, smooth and 
curved downwards. Stem about a foot high, erect, with 
short branches, each whorl with a pale brown, torn sheath 
above it. Spike oblong. ‘This is a graceful species, less 
stiff and more herbaceous than the rest. 
