PHYLLOTAXY, OR LEAF-ARRANGEMENT. 



SECTION II. DISPOSITION OF LEAVES IN THE BUD. 



249. Vernation and .Estivation are terms in general use, under 

 which the disposition ol' leaves in the hud is treated. The first 

 relates to ordinary leaves in this early condition ; the second, to 

 the parts of a flower-bud ; not, however, as respects insertion, 

 or position on the axis, which- is phyllotaxy (231). hut as to 

 249 -.> 251 the wa}-s in which they 



^ f\ are coiled, folded, over- 



^^r l\ ' JL ^^"*^\ l a PP c d, &e., either perse 



^Jf I/)/) fvf Cv^yJ OY inter se. Prcefoliation 



"t^l^i ^^^^S an( l Pr&floration are 



etymologic-ally better 

 terms, substituted by 

 Richard. 1 



250. The descriptive 



J 253 terms which relate to 



individual leaves or 

 parts, whether of foli- 

 age or blossom, mostly range themselves under the heads of 

 plications or of enrolling, and are such as the following, the 

 sectional diagrams of which are copied from the original figures 



would make the two plans equally primordial. But the freedom with 

 which these actually interchange on the same axis greatly favors the less 

 hypothetical view that whorls may be condensed spirals. This assumes 

 only the well-known fact that internodes may be completely non-developed. 

 1 Better formed and more expressive terms: but the Linna\-in ones are 

 most in use, and, though fanciful, are not misleading. In English description, 

 it is as convenient and equally terse to say that the parts arc imbricate, val- 

 vatc, &c., " in the bud." Linnanis, in the Philosophia Botanica, described 

 these dispositions of leaves in the bud under the term i'nllntin, not a happy 

 name, but did not treat of them in the flower-bud. Later, in Termini 

 Botanici (Amoen. Ac-ad, vi. 17(52, reprinted by Giscke in 1781), lie intro- 

 duced the words V<ni<itii> and ^Kxtinititi in their now current botanical sense, 

 to designate, not the time of leafing and of flowering (spring and summer 

 condition), but the disposition of the parts in the leaf-bud and llower-bud 

 (at least of the petals) as respects foldings, coiling, &c., of single parts, and 

 modes of overlapping or otherwise of contiguous parts. The terminology 

 as regards single leaves, Linna-us fixed nearly as it now remains. That of 

 lea ves or their homologues in connection, and as respects the flower-bud, was 

 very imperfectly developed until its importance (and much of its termi- 

 nology) was indicated by Robert Brown, in his memoir on Proteaceae, 1809, 

 in the Prodromus a year later, and in other publications. 



/'/y.n'.s (the Greek name) is coming into use as a general term for the 

 folding, &c., of single parts. 



FIG 'Jl!i-'JM. Linnaean iliagrams of sections of leaves in the bud. 249. Comluph- 

 cate. 250. Plicate or plaited 251. Convolute. 252. Revolute. 253. Involute. 254. 

 Uircinate or Circinal 



