INTEODTJCTIOK. 15 



being outside the others, or by their overlapping each other at least at the 

 top. 



twisted, or contorted, when each petal overlaps the adjoining one on one 

 side, and is overlapped by the adjoining one on the other side. Some bota- 

 nists include the twisted sestivation in the general term imbricate, others 

 carefully distinguish the one from the other. 



In a few cases the overlapping is so slight that the three aestivations can- 

 not easily be distinguished one from the other ; in a few others the sestiva- 

 tion is variable even in the same species, but in general it suppUes a con- 

 stant character in species, in genera, or even in Natural Orders. 

 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 measm-e the shape of a cup 

 or bell. 



urceolate, when the tube is cup-shaped, or nearly globular, contracted 

 at the top, and slightly expanded agam in a narrow i-im. 



rotate, or stellate, when the petals or lobes are spread out horizontally 

 from the base (or nearly so) like a wheel or star. 



hypocrateriforin, or salver-shaped, when the lower part is cylmdrical, 

 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, whetlier it be divided to the base or not. 



infundibulijorm, or funnel-shaped, when the tube is cylindrical at the 

 base, but enlarged at the top into a more or less campanulate Umb, of wliich 

 the lobes often spread horizontally. In tliis case, the campanulate joart, 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, infundibuhform, or other co- 

 rollas, 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 jjart where the 

 corolla first expands, according to which is the most marked. 



The upper orifice of the tube is often called its mouth or its throat. 

 Irregular corollas have received various names, according to the more 

 familiar forms they have been compared to. Some of the most important 

 are the 



bilabiate, or two-lipped corolla, when in a four- or five-lobed corolla 

 the two or three upper lobes, or the two or three lower lobes, are closer 

 placed or more miited together than they are with the tlu-ee or two lower 

 or upper ones, as the case may be. 



personate, when two-lipped, and the orifice of the tube closed by a pro- 

 jection from the base of the upper or lower hp, called a palate. 



ringent, when very strongly two-Upped, and the orifice of the tube very 

 open. 



spurred, when the tube or lower part of a petal has a conical hollow 

 projection, compared to the spur of a cock. 



Tlie above terms are more especially applied to the shape of monopetalous 

 corollas, but most of them are also applicable to those in which the petals 

 are free. 



Terms applied to forms of corolla pecuHar to Pea-flowermg plants. Com- 

 posites, and other Natural Orders, wUl be explained under the respective 

 Orders. 



