x i v OUTLINES OF 



at all, or in two whorls, or composed of a large number of sepals, of which the outer 

 ones pass gradually into bracts, and tbe inner ones into petals. 



97. The Corolla (90) is usually coloured, and of a more delicate texture than the 

 calyx, and, in popular language, is often more specially meant by the flower. Its petals 

 are more rarely in two whorls, or indefinite in number, and the whorl more rarely 

 broken than in the case of the calyx, at least when the plant is in a natural state. 

 Double flowers are in most cases an accidental deformity or monster in which the ordi- 

 nary number of. petals is multiplied by the conversion of stamens, sepals, or even carpels 

 into petals, by the division of ordinary petals, or simply by the addition of supernume- 

 rary ones. Petals are also sometimes very small, rudimentary, or entirely deficient. 



98. In very many cases, a so-called simple perianth (15) (of which the parts are 

 usually called leaves or segments) is one in which the sepals and petals are similar in 

 form and texture, and present apparently a single whorl. But if examined in the 

 young bud, one half of the parts will generally be found to be placed outside the other 

 half, and there will frequently be some slight difference in texture, size, and colour, in- 

 dicating to the close observer the presence of both calyx and corolla. Hence much 

 discrepancy in descriptive works. Where one botanist describes a simple perianth of 

 six segments, another will speak of a double perianth of three sepals and three petals. 



99. The following terms and prefixes, expressive of the modifications of form and 

 arrangement of the corolla and its petals, are equally applicable to the calyx and its 

 sepals, and to the simple pei-ianth and its segments. 



100. The Corolla is said to be monopetalous when the petals are united, either en- 

 tirely or at the base only, into a cup, tube, or ring ; polypetalous when they are all 

 free from the base. These expressions, established by a long usage, are not strictly 

 correct, for monopetalous (consisting of a single petal) should 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 modem botanists have therefore proposed the term gamo- 

 petalous for the corolla with united petals, and dialypetalous for that with free petals ; 

 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 excessively 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 ./Estivation of a corolla is the arrangement of the petals, or of such por- 

 tion 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 in flexed, 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 margins 

 are rolled outwards j plicate, if the petals are folded in longitudinal plaits. 



imbricate, when the whorl is more or less broken by some of the petals being out- 

 side 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 adjoin- 

 ing one wholly inside, the three others intermediate 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 ono 

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

 include the twisted activation in the general term imbricate ; others carefully distin- 

 guish the one from the other. 



103. In a few cases the overlapping is so slight that the three activations cannot 

 easily be distinguished one from the other ; in a few others the activation 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 



