430 



RELATIOM TO ENVIRONMENT. 



anthesis extends over a period of time, as it favors cross pollina- 

 tion, favors tlie formatinn of seed in case conditions slionld lie 





«»- 



Heads of fuller's tCLizel in different stages uf fl^.twering. 



unfavorable at one period of anthesis, distributes the drain on 

 the plant for food, etc. 



B. FLOWER CLUSTERS WITH DETERMINATE INFLORESCENCE. 



829. The simplest mode of determinate inflorescence is a 

 plant with a solitary terminal fltiwer, as in the hepatica, the tulip, 

 etc. The leaves in these two jilants are clustered in the form of a 

 rosette, and the aerial shoot is naked and l)ears the single llower 

 at its summit. Such a flower-shoot is a scdpc. As in the case 

 of the indeterminate inflorescence, so here the larL,'er number 

 of flower-shoots are more complex and spetialized, rcsultini;- in 

 the e\'olution of flower clusters or masses. Accompan}anL; the 

 association of flowers into cluster^ there has licen a reduction in 

 leaf surface on the llower-shool so dial the llowers predominate 

 in mass and are more conspicuous. .Vnionij; the recotjnized 

 modes of determinate inflorescence, the followini; are the chief 

 ones: 



830. The cyme.— In tlie c\mc (he terminal flower on the main 

 axis opens hrst and the remainiiiL!; flowers are home on lateral 

 shoots, which ari.^e from the axils of lea\'es or bracts, below. 



