DO 



THE PLAN OF THE FLOWER. 



1. In the unequal size of like organs (petals of mullein). 



2. In their dissimilar forms or positions (petals of the pea). 



3. In the unequal cohesion of like parts (petals of Lobelia). 



4. In unequal suppressions (stamens of -the Labiate flowers, where, 

 indeed, as in many other flowers, all these phases of irregularity are 

 combined). 



2S6, Flower (magnified) of Myosurns ; a vertical section showing its elongated receptacle, etc. 

 2S7, The same, natural size. 2S8, Flower of Isopyrum biternatum ; vertical section, showing 

 the convex or globular receptacle, etc. 2S9, Flower of rose, showing its excavated torus. 



442. The regular receptacle has no internodes. It bears the 

 several whorls of the flower in close contact with each other, and is 

 usually short and depressed. 



443. Lengthened receptacle. When these whorls are numerous, 

 as in buttercups, tulip-tree, the receptacle is necessarily elongated. So 

 in Myosurus, blackberry, strawberry. In the two latter it imbibes the 



29 nutritious juices of the plant 



and becomes a part of the fruit. 



444. Excavated recepta- 

 cle. On the contrary, the to- 

 rus instead of lengthening may 

 be hollowed out in the center. 

 The carpels of the rose are sit- 

 uated in such a cavity, while the 

 other organs are borne upon its 

 elevated rim. In Nelumbium 

 the carpels are immersed in as 

 many separate excavations in a 

 large, fleshy receptacle. 



445. But the internodes op the 

 torus are sometimes developed, 

 e. g., in noble liverwort a short inter- 

 node between the corolla and calyx 



290, Flower of Cleome pungens, showing its ovary, 

 o, mounted on a. long stypo. 



