-4 



PHANEROGAMS. 



arrangement sometimes occur in definite numbers, more often in larger indefinite 

 numbers. 



When on the other hand the parts of the flowers are arranged in whorls, the number 

 of the whorls, as well as that of the members of each whorl, is constant in the same 

 species, and within larger or smaller circles of affinity. When the number of members of 

 each whorl is the same, and those belonging to the different whorls are placed one over 

 another so as to form orthostichies, I adopt Payer's expression of superposed (instead 

 of the ordinary one of 'opposite'). When the stamens are superposed on the calyx or 

 corolla, they are termed respectively episepalous and epipetalous ; if the members of a 

 whorl fall between the median lines of those of the next whorl above or below, the 

 whorls are alternate ; and Braun calls those flowers encyclic in which the members of all 

 the whorls are equal in number and alternate. It also happens however that members 

 of the same kind arise subsequently between those of a whorl already formed ; as, for 

 instance, five later stamens between the five earlier ones in Dictamnus Fraxinella (Fig. 

 3575 P' 493)j and probably in many eucychc flowers with ten stamens. Members subse- 

 quently introduced in this manner into a whorl may be called interposed. (For further 

 details, vide infra.) 



The consideration of the number of the parts of the flower cannot be separated from 

 that of their relative position. But before entering more minutely upon this subject, the 

 construction of the Floral Diagram must be described. 



The Floral Diagram is constructed differently according to the purpose it is intended 

 to serve. Some treat it as a somewhat free drawing of an actual transverse section of 



FIG. 375. — Diagram of the flower of 

 Liliacete. 



Fig. 376. — Diagram of the flower of 

 Celastrus (after Payer). 



FIG. 377. — Diagram of the flower of 

 Hypericum calycimmi. 



the flower, and indicate on it not merely the number and position, but approximately 

 the form, size, aestivation, cohesion, &c., of its parts. This purpose is however clearly best 

 attained by preparing as accurate drawings as possible of actual transverse sections of 

 the flower-bud, which will then also contain much that would be superfluous for ob- 

 servations of a certain kind. But if it is merely required to represent the number and 

 position of the parts of the flower in such a manner as to render as easy as possible the 

 comparison in this respect of a number of flowers, it is best to disregard all other pro- 

 perties, and to adopt one and the same plan for all diagrams, and that as simple as 

 possible, so as to represent nothing but the variations in the relationships of number and 

 position. This is the only purpose kept in view in the diagrams given in the remainder of 

 this work, of which Figs. 375-377 may serve for the present as examples. They are con- 

 structed according to the rule already given on p. 167 ; the dot above the diagram always 

 represents the position of the mother-axis of the flower ; and the lower is therefore the 

 anterior part. Although mere dots would be sufficient to indicate perfectly the number 

 and position of the parts of the flower, diff"erent signs have nevertheless been chosen for 

 the various separate organs, in order to render the explanation more readily visible to 

 the eye. The leaves of the perianth are represented by arcs of a circle, a kind of mid- 

 rib being indicated on each of the outer whorl of these, or calyx, merely in order to 

 distinguish them at a glance from the inner whorl. The sign chosen for the stamens 

 resembles a transverse section of an anther, but without reference to the position of the 

 pollen-sacs or of their mode of dehiscence whether inwardly or outwardly. When the 



