EdUISETUM. 415 



outline narrowed upwards. Fertile st. short, with few (4 5) 

 sheaths, appearing before the sterile ones. Sterile and fertile st. 

 always distinct. Damp meadows. P. IV. 



2. E. umbrosum (Willd.) ; sterile st. with about 20 striae very 

 scabrous with prominent points particularly above, branches sim- 

 ple with 3 or 4 simple angles, teeth of sheaths blunt \-ribbed but 

 not to the tip, fertile st. simple with many crowded deeply toothed 

 sheaths. S. 2. N. 63. E. Drummondii Hook., E. B, S. 2777. 

 Sterile st. 1 If ft. high, nearly naked below; with many 

 whorls of slender branches in the upper part, having 3- or 4- 

 toothed sheaths ; general outline remarkably blunt at the top. 

 Branched fertile st. with larger sheaths and whorls of about 6 

 branches ; simple fertile st. short (4 6 in.), with many loose 

 and still larger yellowish-white sheaths with black prominent ribs 

 upwards and 1220 teeth. Wet places, rare. P. IV. 



3. E. Telmateia (Ehrh.) ; sterile st. nearly smooth with about 

 30 striae and branches, branches rough doubly-angular simple, 

 teeth of sheaths 2-ribbed, fertile st. simple with many crowded 

 large deeply toothed sheaths. S. 3. N. 67. E.fluviatile Sm., 

 E. B. 2022. Sterile st. 3 6 ft, high; occasionally bearing a 

 small terminal spike ; furnished from top to bottom with whorls 

 of slender branches which have 4 angles each with a longitudinal 

 furrow, and 4-toothed sheaths. Fertile st. stout, 1 foot or more 

 in height, with many pale brown sheaths with 30 40 teeth ; 

 spike large. Wet places. P. IV. 



** Sterile and fertile stems similar, simple or branched. 



4. E. sylvaticum (L.); sterile and fertile st. with about 12 

 furrows and many whorls of slender compound spreading or 

 defiexed branches, sheaths lax ending in 3 or 4 blunt lobes. 

 E. B. 1874. S. 4. IV. 59. St. 1218 in. high. Sheaths of 

 the branches with 3 long acute teeth each \-ribbed to its tip. 

 Fertile st. occasionally simple. Spike blunt. General outline 

 of sterile st. pyramidal, of fertile abrupt. Wet shady places. 

 P. IV. V. 



5. E. limosum (L.); stem nearly smooth with many slight 

 furrows, teeth of sheaths short rigid acute, branches simple 

 whorled or none. St. 24 ft. high. Sheaths rather short. 

 Spike blunt. a. E. limosum (L.) ; st. smooth, barren st. nar- 

 rowing gradually upwards, branches short rigid slightly tapering 

 upright and equalling the joints of the st. from green sheaths 

 often wanting. /3. E.Jlumatile (L.) ; st. subglabrous, barren st. 

 with a lax whiplike end, branches long slender tapering lax 

 exceeding the joints of the st. from dark brown sheaths rarely 

 wanting. In stagnant water. P. VI. VII, 



