REGULARITY 43 



mature organ and not a temporary embryonic state such as the twisting 

 of the corolla in the bud. Torsion of the base of the corolla is shown in 

 Fig. 49, of the stamens in Fig. 50, of the anther in Fig. 51, of the style 

 in Fig. 52, and of the fruit in Fig. 53. Torsion also frequently affects 

 other parts of the plant, especially the stems of flower and leaf. 



The treatment of the subject of position here presented is necessarily 

 superficial and incomplete, omng to our failure to have considered 

 already the subject of leaf -arrangement. There is a direct correlation 

 between the arrangement of foliage-leaves and the parts of the flower. 

 As the arrangement of the former is sometimes by circles or whorls and 

 sometimes by spirals, it follows that some flowers may be arranged on 

 the former plan (Fig. 20), some (at least in part) upon the latter, and 

 such we actually find to be the case. There is no one of the floral series 

 but what at times exhibits in its parts (in most cases when they are 

 numerous) a well-marked spiral arrangement. Such are denominated 

 Acyclic, while those having their parts in true whorls or circles are 

 called Cyclic. 



Flowers Normally Possessing but One Stamen-circle. — It should be 

 noted that the very frequent occurrence of flowers possessing but one 

 stamen-circle, and this alternating with both carpels and petals, has 

 led to the belief that in some plants but one stamen-circle is the rule, a 

 second calyx-circle existing instead of the second stamen-circle. Care 

 should be taken not to confuse the idea of this second calyx-circle with 

 that of the totally different epicalyx. 



Law 3: Regularity. — The parts composing one circle agree in form and 

 size. A flower all of whose circles obey this law is Regular. An illus- 

 tration is found in the flower of Veratrum (Fig. 28). 



Irregularity and How it May Result. — Irregularity may result from 

 abortion (Fig. 44), where three of the upper circle of stamens are 

 different from the other five; from appendaging (Fig. 65), where one of 

 the five petals bears a long spur; or from mere variation in form (Fig. 

 110) or size (Fig. 48). Sometimes, as in the last case, the variation is 

 so slight that the student will be in doubt as to its existence, while at 

 other times an accidental variation in an individual plant may suggest 

 irregularity where it is not a characteristic. Very often an irregularity 

 so slight as to be scarcely perceptible in the open flower may be more 

 conspicuous in the bud. In cases of doubt the relationship of the plant 

 to others whose flowers are regular or irregular may aid to a decision. 



A tendency to antero-posterior irregularity in flowers would appear 

 to be generally characteristic of their higher development. 



