200 
VARIABLE /ESTIVATION 
OF RANUNCULUS BULBOSUS an d R. ACER. 
By L. A. M. Riley, B.A. 
The existing terminology of imbricate aestivation lacks precision 
owing to different terms having been used for the same arrangement 
and the same term having been applied to different arrangements. 
Three main modes of closed aestivation are generally recognized— 
namely, valvate, imbricate, and convolute. The valvate mode and 
its modifications, in which the members meet without overlapping, is 
clearly distinct and presents no difficulties. In the imbricate and 
convolute modes each margin of a member overlaps, or is overlapped 
by, a margin of an adjacent member. Hence these two may be 
treated as subdivisions of one mode, to which the term imbricate has 
been applied in a general sense by some authors. Others, however, 
have restricted the term to those phases with at least one wholly 
exterior and one wholly interior member, or even to one such particular 
phase only. 
In pentamerous whorls four overlapping arrangements are possible 
(see diagram, p. 210). (I) Two members exterior, two interior, and 
one intermediate. (II) One member exterior, one interior, and three 
intermediate, the exterior and interior members not being adjacent. 
(Ill) One member exterior, one interior, and three intermediate, the 
exterior and interior members being adjacent. (IV) Each member 
with one margin exterior and the other interior. 
To these the following terms have been respectively applied by 
Le Maout and Decaisne (Gen. Syst. Bot. ed. J. 1). Hooker, 86 ; 
1873) ; Eicliler (Bliithendiagramme, i. 7 ; 1875); G. Henslow (Trans. 
Linn. Soc. ser. n. Bot. i. 178, t. 25; 1876) ; Asa Gray (Struct. Bot. 
ed. 6, 137, footnote ; 1879) ; Bentham and Hooker (Handb. Brit. 
El. p. xxviii; 1887) :— 
Authority. I. II. III. 
IY. 
Le Maout and 
Decaisne... 
Eichler . 
j* Quincuncial. 
Quincuncial. 
G. Henslow... Quincuncial. 
A. Gray . Quincuncial. 
Bentham and No special 
Hooker ... term. 
Cochleate. 
Cochlear. 
Imbricate. 
Cochlear. 
Half-imbricate. Imbricate. 
Subimbricate. Subconvolute. 
No special 
{ 
term. 
j- Quincuncial. -j^ 
Contorted. 
Contorted 
(gedreht). 
Convolute. 
Convolute. 
Twisted, contorted, 
or convolute. 
A glance at the above table shows that a large majority of 
authorities have used the term quincuncial for the first phase. It 
seems desirable to maintain this usage, although the term denotes an 
arrangement very different from the Latin “quincunx.” For reasons 
given by Asa Gray, the fourth phase should be known as convolute 
rather than contorted. Considerable confusion attends the terminology 
of the second and third phases. Cochlear is ambiguous, having been 
applied to two different phases. Imbricate, being generally employed 
so as to include the first three phases, should not be restricted to one 
of them, and a similar objection applies to half-imbricate and sub- 
Journal or Botany.—Vol. 61. [August, 1923.] q 
