XIII EQUISETINE/E 435 



second stronger one grows. Hofmeister ^ states that the bud 

 is an adventitious one, arising endogenously, but it is much 

 more Hkely that it is an axillary one, like all the later buds, 

 and formed in the axis of the cotyledon. This point does not 

 appear to have been examined by either Sadebeck or Buchtien. 

 This second shoot is much more vigorous, and its leaf-sheaths 

 have four teeth. From the base of this others arise in the 

 same way and in rapid succession. Sometimes the third, or 

 one or more of the later formed basal shoots, bends downward 

 and penetrates the earth, producing the first of the character- 

 istic rhizomes. The first of these have also four-toothed sheaths, 

 but the branches produced from them gradually assume the 

 characters of the fully -developed shoots, some of which 

 ultimately bear sporangia. The first shoots of the sporophyte, 

 even in such species as later branch very freely, produce only 

 an occasional branch, which breaks through the base of the 

 sheath. Whether in these early stems a bud is formed nor- 

 mally at the base of each tooth does not appear to have been 

 investigated. Numerous roots are found at the nodes of these 

 rhizomes, which probably originate, as in the aerial stems, from 

 the bases of the buds in the axil of the sheath. 



The Mature Sporophyte 



On comparing the sporophyte of Equisetum with that of 

 most Ferns, the greatest contrast is in the relative importance 

 of stem and leaves. The stem in all the Equisetineae is extra- 

 ordinarily developed, while the leaves are rudimentary, in strong 

 contrast to their great size and complexity in many Ferns. 

 All species of Equisetum produce a more or less developed 

 underground rhizome, which often grows to a great length and 

 ramifies extensively. This, like the aerial branches developed 

 from it, shows a regular series of nodes and internodes. The 

 latter are marked by longitudinal furrows, and about each node 

 is a sheath whose summit is continued into a number of teeth, 

 varying with the size of the stem. Corresponding to each 

 tooth of the sheath there is developed an axillary bud, which 

 may either at once develop into a shoot, subterranean or 

 aerial, or these buds may remain dormant for an indefinite 

 period, being capable of growing, however, under favourable 



1 Hofmeister (i), p. 303. 



