ORGANS OF REPRODUCTION. 231 



of their margins also; the mode in which those are divitled; and 

 the terminations of petals are also indicated by the same terms as 

 those previously described under similar heads in our chapter on 

 leaves. Thus the petals may be dentate, or serrated; cleft, partite, 

 sected; acute, emarginate, &c. The petals are not however liable 

 to any further division than that of the original one ; thus, al- 

 though sometimes pinnatifid, or pinnatipartite, &c., they are 

 never bipinnatifid, or bipinnatipartite. One term is occasionally 

 used in describing the condition of the borders which has not 

 been alluded to when speaking of leaves. Thus they are said to 

 hQ fimbriated ov fringed, as in some species of Dianthus (^^. 

 460), when they present long thread-like processes. 



In form also, the petals may be either flat, as is usually the 

 case, or they may be concave, tubular, or boat-shaped, &c. 

 The terms used sufficiently explain their meaning. A few 

 anomalous forms of petals will be explained hereafter. In 

 texture they are commonly soft and delicate, but they some- 

 times 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 terms erect, connivent, 

 divergent, patulous, or reflexed, in the same sense as already 

 described when speaking of the sepals (p. 223). 



The petals Uke 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 {fig. 460) ; in the latter, 

 monopetalous or gamopetalous (fig. 464). We shall describe 

 the different kinds of corolla under these two heads. 



1. Polypetalous or Dialypetalous 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, tetrapetalous, 

 of five, pentapetalous, of six, hexapetalous, 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. 421) ; when the petals vary in 

 these particulars, as in the Pea and allied plants (fig. 463), it is 

 said to be irregular. Some forms of these have received special 

 names, which we will now proceed to describe under the two 

 divisions of regular and irregidar polypetalous corollas. 



A. Begular Polypetalous Corollas. — Of these we may mention 

 three forms, A-iz., the cruciform or cruciate; the caryophyllaceous ; 

 and the rosaceous. 



1. Cruciform or Cruciate. — This corolla gives the name to 

 the natural order Crucifera; or Mustard Family. It consists of 

 four petals, usually with claws, as in the Wallflower (fig. 421), 

 Q 4 



