240 



ORGANOGRAPIir. 



cellular processes which grow by additions to their bases or 

 points of attachment to the axis. 



2. The calyx is always developed before the corolla. 



3. When a calyx is polysepalous, or a corolla polypetalous, 

 the component sepals or petals make their first appearance in 

 the form of little distinct papillae or tumours, the number of 

 which correspond to the parts of the future calyx or corolla. 



4. When a calyx is monosepalous, or a corolla monopetalous, 

 the first appearance of these organs is in the form of a little 

 ring, which ultimately becomes the tube of the calyx or corolla 

 as the case may be. When these present lobes or teeth, as they 

 more Qommonly do, they arise as little projections on the top of 

 the ring, the number of which correspond to the future divisions 

 of the calyx or corolla. 



5. All irregular calyces or corollas are regular at their first 

 formation, the cellular papillte from which they arise being all 

 equal in size; hence all irregularity is produced by unequal sub- 

 sequent growth. 



Section 4. — The Essential Organs of Reproduction. 



The essential organs of reproduction are 

 Fi(j 488. the stamens and pistil, which together con- 



stitute the two inner Avhorls of the flower. 

 They are so called because the presence of 

 both is necessary for the production of per- 

 fect seed. The staminal whorl is termed 

 the Andrceciam, and the pistillate the Gy- 

 ncecium. 



Flowers which possess both these organs 

 are called hermaphrodite or bisexual (Jig. 

 422). When only one is present, they are 

 unisexual or diclinous, as in the Carex {fig. 

 (488),WilloAV,&c. {figs. 392 and 393) ; tlie 

 flower is then described as staminate or 

 staminiferous {figs. 393 and 488) when it 

 contains only stamens, and pistillate or pistil- 

 lifcrous when it has only a pistil {fig. 392). 

 When a flower possesses neither stamens 

 nor pistil, as is sometimes the case with the 

 outer florets of the capitula of the Composita;, 

 it is said to be neuter. Wlicn the flowers 

 are unisexual, botli staminiferous and pis- 

 tilliferous flowers may be borne upon the 

 same plant, as in the Hazel, Oak, Cuekow 

 Pint {fig. 380), and Curcx, in which case 

 tlie ])lant is stated to be moiurcions ; or upon 

 (liUcrent plants of the same species as in 

 Willow {figs. 392 and 393), Hemp, and 



Fig. 48«. Unisexual 

 staminate flower of 

 a spccicH of Cari'x. 

 The filaments arc 

 long andcapiUary, 

 and the antlur') 

 pendulous aud in- 

 nate. 



