&XVlli OUTLINES OF BOTANt. 



valvate, when they are strictly whorled in their whole length, theii 

 edges being placed against each other without overlapping. If the edges 

 are much inflexecL the aestivation is at the same time induplicate ; 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 quincuncially imbricate when one 

 petal is outside, and an adjoining one wholly inside, the three others inter- 

 mediate and overlapping on one side ; bilabiate, 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 aestivation in the general term 

 imbricate : others carefully distinguish the one from the other. 



103. In a few cases the overlapping is so slight that the three aestiva- 

 tions cannot easily be distinguished one from the other ; in a few others the 

 aestivation 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 limb, 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 upper lip, from 



