XXVII1 OUTLINES OF BOTANY. 
valvate, when they are strictly whorled in their whole length, their 
edges being placed against each other without overlapping. If the edges 
are much inflexed, the estivation is at the same time imduplicate; invo- 
lute, if the margins are rolled inwards; reduplicate, if the margins project 
outwards into salient angles; revolute, if the margins are rolled outwards; 
plicate, if the petals are folded in longitudinal plaits. 
imbricate, when the whorl is more or less broken by some of the petals 
being outside the others, or by their overlapping each other at least at the 
top. Five-petaled imbricate corollas are guincuncially imbricate when one 
petal is outside, and an adjoining one wholly inside, the three others inter- 
mediate and overlapping on oneside; bilabzate, when two adjoining ones are 
inside or outside the three others. Imbricate petals are described as 
crumpled (corrugate) when puckered irregularly in the bud. 
twisted, contorted, or convolute when each petal overlaps an adjoining 
one on one side, and is overlapped by the other adjoining one on the other 
side. Some botanists include the twisted estivation in the general term 
imbricate: others carefully distinguish the one from the other. 
103. In a few cases the overlapping isso slight that the three sestiva- 
tions cannot easily be distinguished one from the other ; in a few others the 
eestivation is variable, even in the same species, but, in general, it supplies 
a constant character in species, in genera, or even in Natural Orders. 
104. In general shape the Corolla is 
tubular, when the whole or the greater part of it is in the form of a 
tube or cylinder. 
campanulate, when approaching in some measure the shape of a cup 
or bell. 
urceolate, when the tube is swollen or nearly globular, contracted at 
the top, and slightly expanded again in a narrow rim. 
rotate or stellate, when the petals or lobes are spread out horizontally 
from the base, or nearly so, like a wheel or star. 
hypocrateriform or salver-shaped, when the lower part is cylindrical 
and the upper portion expanded horizontally. In this case the name of 
tube is restricted to the cylindrical part, and the horizontal portion is called 
the amb, whether it be divided to the base or not. The orifice of the tube 
is called its mouth or throat. 
infundibuliform or funnel-shaped, when the tube is cylindrical at the 
base, but enlarged at the top into a more or less campanulate limb, of 
which the lobes often spread horizontally. In this case the campanulate 
part, up to the commencement of the lobes, is sometimes considered as a 
portion of the tube, sometimes as a portion of the limb, and by some 
botanists again described as independent of either, under the name of 
throat ( fauces). Generally speaking, however, in campanulate, infundi- 
buliform, or other corollas, where the lower entire part passes gradually into 
the upper divided and more spreading part, the distinction between the 
tube and the limb is drawn either at the point where the lobes separate, or 
at the part where the corolla first expands, according to which is the most 
marked. 
105. Irregular corollas have received various names according to the 
more familiar forms they have been compared to. Some of the most im- 
portant are the 
bilabiate, or two-lipped corolla, when, in a four- or five-lobed corolla, 
the two or three upper lobes stand obviously apart, like an wpper lip, from 
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