ORGANS OF REPRODUCTION. 361 



{fig. 770), and carpels of Liriodendron {fig. 589, c), it cannot be 

 well determined, in which case the symmetry is disguised or de- 

 stroyed; which is also tlie case if the whorls are crowded together. 



h. Chnrisis or deduplicatioii. —Tb\s h generally looked upon 

 by botanists as another means of multiplication of the parts of 

 a' flower. It consists in the division or splitting of an organ in 

 the course of its development, by wliich two or more organs are 

 produced in the place of one Chorisis differs from augmenta- 

 tion in the fact, that it not only increases the number of parts, 

 but also interferes Avith their regular alternation ; for aug- 

 mentation does not necessarily interfere with alternation, it 

 only obscures it when the number of additional parts is ex- 

 cessive, or when the whorls are crowded togetlier. 



Chorisis may take place in two waj^s, either transversely, 

 when the increased parts are placed one before the other, which 

 is called vertical, parallel, or transverse chorisis ; or collaterally, 

 when the increased parts stand side by side, which is termed 

 collateral chorisis. Transverse chorisis is supposed to be of frc- 



Fig. 770. Fig. 771. 



Fig. 770. Diagram of the flower of Clematis (Banunctilacece) Fig. 771. Dia- 

 gram of the flower of Bhamnus cutJiaiticus, Buckthorn. 



quent occurrence; thus the petals of the Lychnis (fig. 486), and 

 many other Caryophyllaceous Plants, exhibit a little scale on 

 their inner surface, at the point where the limb of the petal is 

 united to the claw. A somewhat similar scale, although less 

 developed, occurs at the base of the petals of some species of 

 Ranunculus (fig. 483). The formation of these scales is sup- 

 posed by many, to be due to the chorisis or unlining of an inner 

 ])ortion of the petal from the outer. Other botanists consider 

 these appendages as deformed glands. Each petal of Parnassia 

 (fig. 4 85) has at its base a petal-like appendage divided into 

 a number of parts, somewhat resembling sterile stamens; this is 

 also stated to be produced by transverse chorisis. 



In the natural orders Khamnaceae (fig. 771), Byttneriacea% 

 &c., the stamens are opposite to the petals, hen:e they are sup- 

 posed by many botanists to be produced by chorisis from the 

 corolla ; others, however, explain this opposition of parts by 

 supposing the suppression of an intermediate whorl (sec p. 364). 



