200 



OEGANOGBAPHY. 



a. The true Cyme. — This term is commonly applied to a definite 

 inflorescence which is more or less branched, the whole being 

 developed in a corymbose or somewhat umbellate manner, so as 

 to assume either a flattened head, as in the Laurustinus {fig. 407), 

 Dogwood and Elder ; or a rounded r ne, as in the Hydrangea ; or 

 more or less spreading as in the Chickweed {fig. 408). In the 

 more perfect and compact form of cyme, as found in the Laurus- 

 tinus and Elder, the flower-buds are all nearly perfect before any 



Fig. 408 



Fig. 408. Cyme of a species of Chickweed (Cerastium). a'. Primary axis 

 terminated by a flower, a", a". Secondary axes, two in number, arising 

 from the axils of opiiosite ))racts b, and terminated also by flowers. 

 a'", a'", ft'", «"'. Tertiary axes, four in number, arising from l)racts b, 

 and bearing otlier bracts b, from wiiicl! tlie quaternary axes, eight in 

 number, arise, a"", a"", a"". The flowers are more developed on the 

 primary axis than on the other axes ; thus the one terminating that 

 axis is in the state of fruit ; the flowers of the axes of ft" and a'" are 

 also in fruit, hut less developed thaji that of «', while the flowers of 



a"" are lully expanded. Fig. 409. Cymose inflorescence of the 



Ci-ntfiury {Erythrcca Centauriuin). a', a", a'", a"". Floral axes. /',/", 

 f"',f"". Flowers terminating those axes respectively. The flowers 

 will be observed to be most developed in proportion to their age; 

 thus /' is in the state of fruit, /", f" expanded,/", /", /"', and the 

 others still in bud. 



of them open, and then the flowering takes place rapidly, com- 

 mencing in the centre of the cyme, and then in the centre of each 

 of its divisions, and thence proceeding in an outward direction ; 

 and as the central flower of each cluster corresponds to the apex 

 of a branch, the expansion of the whole is centrifugal. By 

 attention to this order of expansion such cymes may be always 



