278 HOFMEISTER, ON 



sides these shoots others are developed here and there 

 on individual joints of old stems : the latter have a lateral, 

 not an upward direction ; their colour in the young state 

 is a deep citron-yellow, and their leaf-sheaths are of a deep 

 black-brown. Unlike those first described, they are not 

 blunt at the top, but the connivent tips of the sheathing 

 leaves of the terminal bud form a sharp apex. These 

 shoots are the foundation of the creeping rhizome, and some- 

 times attain a length of twenty feet. When they emerge 

 from the leaf-sheaths of the mother-shoot they are of the 

 thickness of a slender goose-quill, but afterwards by expan- 

 sion of their cells, and by gradual increase in the number 

 of the cells of the new internodes in a diametral direction, 

 they attain from half to three-fourths of an inch in thick- 

 ness. From the bases of their leaf-sheaths a few shoots are 

 produced separated from one another by considerable in- 

 tervals (by several internodes, which produce no adventitious 

 buds), and which are destined partly for development above 

 ground, and partly for the formation of new Rhizomes. 



In those species of Equisetum which are found in damp 

 localities away from the light, a girdle of adventitious roots 

 is formed at each node of the stem, on a level with the 

 septum which traverses the pith cavity, and close under- 

 neath the rudiments of the adventitious buds. They 

 originate close underneath the bark, immediately below the 

 lower ends of the vascular bundles of the next superior 

 internode, and consequently meet the upper ends of the 

 septa which separate the cortical air-cavities of the next 

 lower internode. In the lower nodes of the vigorous 

 autumn shoots one at least, usually two, and often three 

 such adventitious roots are formed close to one another. 

 At an early period the cells of that portion of the partition 

 wall of two cortical air-cavities which leads from the 

 adventitious roots to the convergent prolongations of 

 the vascular bundle are transformed into a single vascular 

 bundle traversed by numerous short spiral vessels. The 

 origin of these thick vascular bundles, which are attached 

 to the spreading prolongations of the vascular bundles 

 of the internode, renders the course of the vascular bundle 

 of the stem within the node quite indistinct ; they 



