THE HIGHER CRYPTOGAMIA. 277 



the cells of the tissue which surrounds* the circle of vas- 

 cular bundles multiply vigorously. Vigorous adventitious 

 buds are formed at the base of the rudimentary leaf of such 

 internodes ; seldom more than two in the same internode. 

 The cellular tissue of the swollen internodes contains starch 

 and a good deal of sugar, I believe not crystallized. 

 The different habit of the species of Equisetum depends upon 

 the relation of the adventitious lateral shoots to the principal 

 shoot. In all the above-named species (arvense, pratense, 

 variegatum, liyemale, pahstre, limosum), the lowest leaves 

 of those shoots which have completed their subterranean 

 development, send out vigorous shoots destined for develop- 

 ment in the following season, a process which brings to 

 mind the buds which occur in the cataphyllary region of 

 many phasnogams. These shoots are the least developed 

 in Eq. arvense ; they are of an elongated cylindrical form, 

 and very beautiful and vigorous in Eq. pratense and limosum. 

 In the latter species they protrude, even in autumn, for 

 a distance of several inches from the base of the sheathing 

 leaves ; in Equisetum pahstre they appear at the beginning 

 of spring; in Eq. hjemale at the end of April. Those 

 of Eq. limosum deserve a closer investigation, not only 

 on account of many peculiarities dependent upon habitat, 

 but also on account of the injury produced by its abundant 

 growth in the richest water-meadows of North Ger- 

 many, where the hay is frequently uneatable from the ad- 

 mixture of numerous shoots of the Equisetum. As in the 

 other species of the genus, the lower part of each shoot 

 (unlike the portion above ground), does not die until the 

 autumn. The epidermis of this portion of the stem assumes 

 a beautiful red-brown colour; from one to three shoots, 

 destined for development above ground in the following- 

 year, burst forth in an upward direction out of the hollow 

 cylindrical leaves, whose upper portion dies and withers. 

 The epidermis of these winter shoots is of the colour of 

 ivory, and the tips of their leaves of a chestnut-brown. If 

 the shoots are exposed to the light, chlorophyll is developed, 

 even in autumn, in the cells of the circumference. Be- 



* Compare Bisckoff ' Kryptogainisclie Gewach.se,' Numb., 1828, Heft i, 

 p. 29. 



