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teeth of E. Mackaii and variegatum The sheaths, havmg first split 

 longitudinally along the furrows, fall off before the plant has decayed. 



The sheaths of E. Mackaii invariably bear teeth such as are de- 

 scribed above. They remain longer on the plant than those of E. 

 hyemale, and the teeth and bristles seldom, if ever, fall off before them. 



In E. variegatum the bristle alone is usually deciduous. The teeth 

 remain till the sheaths decay, which they do in the same manner as in 

 E. Mackaii. In both the teeth of the uppermost sheath differ from 

 the rest, only in being larger and in having shorter bristles. 



The sheaths of all three turn more or less white before their final 

 decay. When they begin to split or fall off, the part of the internodes 

 which they have covered is of a pale green colour, like that of the 

 sheath in its first stage. Soon after it begins to turn black and swell, 

 and thus the plants in extreme old age become bent and geniculated. 

 This, however, is quite different from the sinuous appearance which 

 the stem sometimes assumes when in perfect vigour. 



Catkins. — These, like the other parts of the plant, are well de- 

 scribed by Mr. Newman. While the catkins of E. hyemale, in one of 

 the stations on the Dee, expand freely and shed their seed or pollen, 

 I have not in any case observed those of E. Mackaii or variegatum to 

 expand at all. They appear to ripen without expanding or rising 

 fully out of the sheath. 



On the top of many stems of E. hyemale I observed a pile of small, 

 dark brown, membranous, elastic, conical, inverted sheaths, of the 

 same substance as the teeth of the sheath which embraces the catkin, 

 increasing in width upwards, and so closely embracing each other that 

 the rim only of each is seen, except the highest and largest, which 

 gives the top of the pile a conical shape. Although scarcely an inch 

 in length, it resembles an inverted abortion of the plant. Its lower 

 end is at first inserted in the uppermost sheath, and surrounded by 

 several small sheaths of a texture similar to its own, and placed within 

 each other. It is afterwards quite protruded, and gradually falls off, 

 leaving a flexuose apex, somewhat like that of the catkin, whose for- 

 mation I am persuaded it precedes. On dissecting the top of several 

 stems from which the pile of cones seemed but recently to have fallen, 

 I found the germ of the catkin completely enclosed within its sheath, 

 the teeth of which, not yet separate, form by their union the apex 

 which appears when the pile falls off. Dissection, however, when 

 the cones are present, seems often to discover an abortive germ. The 

 number of inverted sheaths in one of these piles is about twelve ; what 



