Fei5. 1893.] LOTANICAL SOCIETY OF EDINBURGH, 579 



Each of the leaves borne on a spine-branch, the two pro- 

 phylls inchided, bears in its axil a spine-branch with at 

 least two prophyllate spine-leaves and frequently one or 

 more higher leaves occupying positions similar to those 

 assumed by the leaves on the first spine-branch. 



The indefinite branches which arise as accessory structures 

 below the spine-branches, or as axillary branches in the 

 axils of the cotyledons and lower leaves, but which do not 

 appear in either position till the beginning of the second 

 year, bear, like the spine-branches, two lateral prophylls 

 which are, however, not spine-leaves in this case but scale- 

 leaves somewhat triangular in outline, very small, and 

 borne close to the base of the branch. These are followed 

 by two leaves placed almost above the prophylls, but in 

 both cases rather nearer the axillant leaf. With the next, 

 i.e. the third leaf, a ^ left to right spiral commences, and 

 it is so placed that the second leaf of the spiral, i.e. the 

 fourth leaf on the branch after the prophylls, lies in the 

 plane of the axillant leaf. 



This i spiral passes over gradually into a f spiral in 

 such a way that the sixth leaf, or thereabouts, of the ^- spiral 

 is placed posteriorly in the median plane, and is also the 

 first leaf of the permanent § spiral of the branch. The 

 earlier leaves of these branches, unlike those of the spine - 

 branches, are soft, more or less scale-like structures, but 

 these are gradually replaced by spine-leaves as their 

 distance from the base of the branch increases. 



These spine-leaves, but not the earlier soft leaves of an 

 indefinite branch, bear spine-branches in their axils, and 

 in this, as well as the character of their leaves, these 

 branches repeat to a certain extent the characteristics of 

 the main stem. 



Not unfrequently these so-called indefinite branches 

 terminate abruptly in a spine, but even so, are in most 

 cases much longer than the axillary spine-branches, though 

 not so long as other indefinite branches which continue to 

 grow for at least one entire season. The spine-branches, 

 which arise on the main stem in the first season, and on 

 the indefinite l)ranches, which take origin below them, in 

 the second season, bear, as has been mentioned above, 

 spine-branches ; but these, like the primary spine-branches 



