XXVI INTRODUCTION. 



apply rather to a corolla really reduced to a single petal, which would then be 

 on one side of the axis ; and polypetalous is sometimes used more appropriately 

 for a corolla with an indefinite number of petals. Some modern botanists have 

 therefore proposed the term gamopetalous for the corolla with united petals, 

 and dialypetalous for that- with free petals j but the old established expressions 

 are still the most generally used. 



101. When the petals are partially united, the lower entire portion of the 

 corolla is called the tube, whatever be its shape, and the free portions of the 

 petals are called the teeth, lobes, or segments (39), according as they are short or 

 long in proportion to the whole length of the corolla. When the tube is ex- 

 cessively short, the petals appear at first sight free, but their slight union at the 

 base must be carefully attended to, being of importance in classification. 



102. The fBstivation of a corolla is the arrangement of the petals, or of 

 such portion of them as is free, in the unexpanded bud. It is 



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 aestivation is at the same time induplicate ; involute, if the margins 

 are rolled inward; reduplicate, if the margins project outwards into salient 

 angles ; revolute, if the margns 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 quincuncialhj imbricate when one petal is 

 outside, and an adjoining one wholly inside, the three others intermediate and 

 overlapping on one side ; bilabiate, when two adjoining ones are inside or out- 

 side 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 aestivations 

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

 tion 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 i3 



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 re- 

 stricted 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, infundibuliform, or other corollas, where the lower 



