108 BRITISH PERNS. 



branched. The upper whorls have fewer branches. The 

 whorls are most crowded towards the top of the stem, and 

 there also the branches are about the full length six or 

 eight inches; lower down the stem the branches become 

 shorter, and the whorls more distant. The stems measure 

 about an inch and a half in diameter at the _ stoutest part, 

 and from this point decrease upwards, becoming slender at 

 the point. The surface is smooth, with mere indications of 

 about thirty faint lines extending into the sheaths, and there 

 becoming more apparent. The sheaths set close to the 

 stem, or nearly so, and are half an inch long, green below, 

 with a dark-brown ring at top, and divided at the margin 

 into slender, bristly, dark-brown teeth, with paler membra- 

 nous edges, and frequently adhering together in twos and 

 threes. The branches have eight or ten ribs united in pairs, 

 and their sheaths terminate in four or five teeth. 



The fertile stem is erect, simple, from nine inches to a foot 

 or more high, succulent, pale brown, and smooth. From 

 each of the numerous joints arises a large loose funnel- 

 shaped sheath, the upper ones being largest ; they are dis- 

 tinctly striated, and terminate in thirty to forty long, slender 

 teeth. The catkins are large, between two and three inches 

 long. 



A section of the barren stem shows an outer surface with- 

 out ridges and furrows, and in the very narrow cylinder of 

 the stem occiir two circles of cavities, the outer one consist- 

 ing of large openings, those of the inner minute, and alter- 

 nating with the larger. The central cavity is very large, the 

 tissue of the stem being reduced to a very narrow ring. 



This is a widely-dispersed and rather common plant, 

 occurring on moist banks and in muddy places, by the sides 

 of streams and the margins of muddy pools. The nature of 

 the soil would seem to be of small importance, provided it 

 has its necessary degree of moisture, for it is recorded as 

 occurring both in sandy and in clayey soils, as well as in 

 muddy pools. It is frequent in Ireland ; and is found both 

 in Scotland and Wales. 



THE SHADE HOKSETAIL. 



This plant is the Equisetum pratense of botanists ; and has 

 been also known in this country as E. umbrosum, and E. 

 Drummondii. 



The fertile and barren stems are quite dissimilar in their 

 appearance. The former are short, quite simple, and termina- 



