224 ORGANOGRAPHY. 



soft and delicate, but they sometimes differ widely from this, 

 and become thick and fleshy, as in the Stapelia ; or dry and 

 membranous, as in Heaths ; or stiff and hard, as in Xylopia. 



In describing their direction, we use the tevvixs erect, connivent, 

 divergent, patulous, or refiexed, in the same sense as already de- 

 scribed when speaking of similar conditions of the sepals. 



The petals like the sepals may be either distinct, or more or 

 less united into one body. In the former case, the corolla is 

 said to be 'polypetalous or dialypetalous {figs. 419 and 458) ; in 

 the latter ononoj^etalous or gamopetaloiis {figs. 462-464). The 

 same objection applies to the use of the term monopetalous as 

 to that of monosepalous already mentioned, but we shall con- 

 tinue to employ it from its being the one more commonly in 

 use. We shall describe the different kinds of corolla under 

 these two heads. 



1. PoLYPETALOus OR DiALYPETAious CoROLLA. — The num- 

 ber of petals which enter into the composition of the corolla is 

 indicated, as in the case of the polysepalous calyx, by the prefix 

 of the Greek numerals. Thus a corolla of two petals is said 

 to be dipetalous, of three, tripetalous, of four, ietrapetalous, of 

 five, pentapetalous, of six, he.vaijetcdous, of seven, heptapetalous, 

 of eight, octopetalous, and so on. 



When the petals are all of the same size and form, and ar- 

 ranged in a symmetrical manner, the corolla is termed regular, 

 as in Cruciferous flowers {fig. 419); and when the petals vary 

 in these particulars, as in the Pea and allied plants {fi.g. 461), 

 it is said to be irregidar. Some forms of polypetalous corollas 

 have received special names, which we will now proceed to 

 describe under the two divisions of rcgtdar and irregidar. 



A. Regidar Polypitalous Corollas. — Of these we may mention 

 three forms, viz., the cruciform or o'ticiate ; the caryophyllaceous ; 

 and the rosaceous. 



1. Cruciform or Cruciate.— llh\s corolla gives the name to 

 the natural order Cruciferce or Cahhage Order. It consists of 

 four petals, usually with claws, as in the Wallflower {fig. 419), 

 and Stock, but sometimes without claws, as in the Celandine, and 

 the whole arranged in the form of a cross. 



2. Caryophyllaceous. — This consists of five petals, with long 

 claws enclosed in the tube of the calyx, and with their limbs 

 commonly placed at right angles to the claws, as in the Campion, 

 Single Pink {figs. 458 and 459), Carnation, and Catchfly. 



3. Rosaceous. — This is composed of five petals, without, or 

 with very short claws, and spreading in a regular manner, as in 

 the Strawberry {fig. 439) and Single Eose {fig. 460). 



B. Irregidar Polypetalons Corollas. — There are many anoma- 

 lous forms of irregular polypetalous corollas, as in the Monks- 

 hood (Aconitum), and Heartsease, to which no particular 

 names are applied. There is one form, however, which is of 

 much importance, namely, 



