PERNS OP GREAT BRITAIN. 161 



tail, or Great Mud Horsetail). — Barren stems erect, with 

 thirty to forty branches in each whorl; fertile stems with 

 loose sheaths. This is the largest of our British Horse- 

 tails. It is a very graceful plant, and when growing in 

 any quantity, it might remind one of those pictures of 

 Oriental palm-groves famihar to aU readers of Eastern 

 travel. It is the barren stem of this Horsetail which is 

 so handsome, growing erect to a height of six or seven 

 feet, decked from its summit nearly to its base with 

 spreading whorls of delicate green branches; and few 

 would see a luxuriant specimen on the stream-side with- 

 out admuing its grace. On the stouter part of this tall 

 stem the whorls consist of from thirty to forty branches, 

 which are again branched. The whorls on the upper 

 part are very numerous, and the branches six or eight 

 inches long ; but towards the base the whorls are more 

 distant, and the branches shorter. The stems, which 

 are pale green, are at their thickest part of the size of 

 a stout walking-stick, gradually tapering upwards, and 

 becoming very slender at the top. Their smooth sur- 

 face is delicately marked with numerous lines, which, 

 running on into the sheaths, become there more distinct. 

 The sheaths are about half an inch long, the lower part 

 green, the upper encircled by a dark brown ring, and 

 they fit the stem closely. The teeth are slender, dark 

 brown with white edges, and often growing in twos or 

 threes together. The branches have frequently at their 

 second joints from two to five secondary branches ; and 

 their sheaths terminate in four or five teeth, each of 

 which extends into a slender black bristle with two 



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