ITS SYMMETRY. 



239 



are two or more circles of the same kind of organ ; as in Sedum, 

 where there are two sets of stamens, five in each ; in the Barberry, 

 where there are two or more sets of sepals, two 

 of petals, and two of stamens, three in each 

 set, &c. A complete flower (as already de- 

 fined, 416) is one that possesses both sorts of 

 floral envelopes, calyx and corolla, and both 

 essential organs, viz. stamens and pistils. 



437. The simplest possible complete and 

 symmetrical flower would be one with the ca- 

 lyx of a single sepal, a corolla of a single pet- 

 al, a single stamen, and a single pistil ; such 

 as is represented in the annexed diagram, in 

 connection with the two-ranked arrangement 

 of the leaves (Fig. 276). Each constituent 

 of the blossom represents a phyton, with its 

 stem part reduced to a minimum, and its leaf 

 part developed in a peculiar way, according 

 to the rank it sustains and the office it is to 

 fulfil. That there are short internodes be- 

 tween consecutive organs in the flower is 

 usually apparent on minute inspection of its 

 axis, or receptacle ; and some of them are 

 conspicuously prolonged in certain cases. 

 But they are commonly undeveloped, like the 

 axis of a leaf-bud, so that the organs are 

 brought into juxtaposition on a short, mostly 

 conical receptacle, and the higher or later- 

 formed parts are interior or inclosed by the 

 lower. 



438. Perhaps the exact case of a flower at 

 once so complete and so simple is not to be 

 met with. For, when the stamens and pis- 

 tils are thus reduced to the minimum number, the floral envelop 

 one or both, commonly disappear, a n the Mare's-tail (see Ord. 

 OnagraceaB). Nor is the production f seed often left to depend 

 upon a single organ ; but the essential, and with them the protect- 



F1G. 276. Diagram of a plant, with a distichous arrangement of the phytons, carried 

 through the complete flower, of the simplest kind, consisting of, a, a sepal; b, a petal; c, a 

 stamen ; and d, a pistil : br is the bract or uppermost proper leaf. 



