“ESTIVATION AND ITS TERMINOLOGY. 188 
one half exterior, and one interior or overlapped, the estiva- 
tion accords with 3 phyllotaxy. When of eight or higher 
numbers the spiral order is usually all the more manifest. 
When of four or six, the case is one of whorls (opposite 
leaves representing the simplest whorl), either of a pair of 
whorls (as in Epimedium, Berberis, etc.), or a single whorl, 
the parts of which have overlapped in cyclic order. 
(2) As to the terminology. Linnzus in the “ Philosophia 
Botanica” treats only of vernation, there termed “ Foliatio.” 
For this the former term was substituted, and that of <estivation 
for the disposition of petals in a flower-bud, introduced, as I 
suppose (not having the volume to consult), in the Termini 
Boitanici, published in the sixth volume of the “ Amcenitates 
Academice,” 1762. I refer to it only through Giseke’s edi- 
tion, 1781. Here the terms are convoluta, imbricata, condu- 
plicata, defined only by reference to the section vernatio, and 
valvata, unhappily explained by a reference to the glumes of 
Grasses, also “ inzequivalvis; si magnitudine discrepant.” 
Imbricata is the only term besides valvata which directly 
relates to the arrangement of petals, ete., inter se; and the 
reference takes us back to something “ tectus, ut nudus non 
appareat,” covered as with tiles, we may infer. In the “ Phi- 
losophia Botanica,” under the section Foliatio, the definition 
of imbricata is “‘ quando parallele, superficie recta, sibi in- 
vicem incumbunt.” This would apply either to mode I, or 
mode II, according as invicem is understood ; but the dia- 
gram (tab. x. 6) shows that case I is intended. Convoluta 
refers to the rolling of a petal or leaf by itself, as does con- 
duplicata to its folding; but Linnzus gives two figures, one 
of a single rolled-up leaf, the other of one leaf rolled up within 
another. 
Finally, among the modes of vernation indicated by Lin- 
nus, there is one which it is important here to notice, relat- 
ing as it does to the arrangement of a pair of leaves in the 
bud, and evidently quite as applicable to a whorl of a larger 
number of parts than two; 7. e.: 
“ Obvoluta, quum margines alterni comprehendunt oppo- 
siti folii marginem rectum” (Philosophia Botanica, 105). 
