88 



ORGANOGEAPHY AND GLOSSOLOGY. 



symmetry and regularity ' as synonymous, and as implying a similarity between the 

 leaves of a floral whorl; this relation including: l,the/orm; 2, the number; 3, the 

 independence ; 4, the relative position of the parts of flowers : we have thus the sym- 

 metry of form, of number, of disjunction, and of position. Symmetry of form is 

 regularity taken in its usual sense ; as when portions of a whorl are alike, or when, 

 being different, the one sort alternates with the other, so as to present a symmetrical 

 whole around a common centre ; this regularity might be termed rayed symmetry 

 (calyx and corolla of Columbine, fig. 31 ; Wallflower, fig. 7 ; and Buttercup). A whorl 

 that is not thus symmetrical is said to be irregular ; though its two sides (or halves) 

 may resemble each other, thus being analogous to the longitudinal 2 symmetry of 

 animals, which is opposed to the rayed symmetry of Zoophytes. The corollas of the 

 Heartsease (fig. 170), Cytims (tigs. 253, 254), Tropatolum (fig. 210), are irregular, but 

 longitudinally symmetrical. The whorl is called regular, even though it forms a 

 depressed spiral ; but if the floral axis lengthens sensibly, the rayed symmetry dis- 

 appears, and, to describe the symmetry, recourse is had to the comparative length 

 of the spiral ; thus the symmetry of the carpels is hemispheric in the Strawberry 

 (fig. 401), conical in the Raspberry (fig. 402), spiked in Adonis (fig. 404). 



Perfect numerical symmetry occurs when all the whorls consist of the same 

 number of parts, as in Crassula, which has five sepals, petals, stamens and carpels. 



Disjunctive symmetry occurs when the pieces of each whorl are entirely sepa- 

 rated, and each whorl is entirely free (Columbine, Hellebore}. Symmetry of position 

 occurs when the pieces of each whorl alternate with those of the preceding and 

 succeeding ; and the normal position of the whorls (calyx, corolla, androecium, pistil) 

 is undisturbed (Crassula rubens). Many botanists, regarding regularity as the normal 

 feature in plants, assume it to be the primitive type adopted by Nature ; they there- 

 fore look upon a combination of the above-named symmetries as indicating the 

 normal condition of the flower ; which should thus consist of 

 four whorls, each composed of the same number of leaves, all 

 equal, free, alternating successively, and arranged in the order 

 of calyx, corolla, andrcecium and pistil. 

 Further, such a primitive type, whether real 

 or imaginary, may be more or less com- 

 pletely and permanently modified by various 

 single or combined causes, of which the prin- 

 cipal are, inequality of development, cohe- 

 sion or symphysis, multiplication, doubling, 

 suppression and abortion. This hypothe- 

 sis has contributed largely to the progress 

 of organography, by stimulating investigations into the comparative anatomy of 

 floral organs. 



To ascertain the amount of symmetry a flower displays, its bud must be cut 



1 Symmetry in English and American works or equal in number ; regularity, that the parta of a 

 implies that the parts of successive whorls are isometric whorl are equal and similar. ED. 



Better called bilateral. ED. 



469 bis. Linaria. 

 Monstrous flower. 



469. Diagram of an ideal 



perfectly 

 symmetrical flower. 



