ESTIVATION AND ITS TERMINOLOGY. 1 



The term aestivation, to denote the arrangement of the 

 parts of the calyx, corolla, etc., in the bud, as well as that of 

 vernation for leaves in a leaf -bud, was introduced by Linnaeus. 

 He did not elaborate the former subject as he did the latter, 

 and the few terms given to the modes he recognized are for 

 the most part defined merely by a reference to their use in 

 vernation. ^Estivation as a botanical character is compara- 

 tively recent, and its terminology is not yet quite satisfactorily 

 settled. I propose to consider, (1) what the leading modes 

 are, and (2) how they are to be designated. 



(1) In the first place, the modes of aestivation may be con- 

 veniently divided into two classes, those in which the parts 

 overlap, and those in which they do not. 



Of overlapping aestivation, only two principal kinds need 

 be primarily distinguished, namely : 1. where some pieces 

 overlap and others are overlapped, i. e., some have both 

 margins exterior and others both margins interior or cov- 

 ered ; 2. where each piece of a circle is overlapped by its 

 neighbor on one side while it overlaps its neighbor on the 

 other. There are mixtures and subordinate modifications of 

 these two, but no third mode. 



In aestivation without overlapping, there is, first, the rare 

 case in which the parts of the whorl or cycle never come into 

 contact in the bud ; and, secondly, that in which they impinge 

 by their edges only. There is also the case in which both 

 margins of each piece are rolled or bent inward, and the rarer 

 one in which they are turned outward ; and the apex of each 

 piece may comport itself in any of these ways. But these 

 dispositions are those of the pieces or leaves taken separately, 

 and the terms applied to them are the same as in vernation or 

 1 American Journal of Science and Arts, 3 ser., x. 339. (1875.) 



