266 



STRUCTURE AND VITAL PROCESSES OF PLANTS 



Fie:. 254 



the same direction or in alternate directions. Cymose inflores- 

 cences may be studied in Ipom^ea, Clerodendron, Ixora, and in 



the Labiata^-; 



In Ixora the pedi- 

 cels are much reduced, 

 so tliat a fascicle of 

 flowers is formed. The 

 Labiata? have small 

 fascicles in the axils of 

 their opposite leaves, thus forming 

 cymose whorls or verticels. Race- 

 mose and cymose inflorescences 

 may sometimes be found in com- 

 bination, as for instance, in Clero- 

 dendron infortunatum. 



(iii) Scents. — Strong and 



various scents are also great helps 



to attract insects. The bee-tribe 



and butterflies are specially 



attracted by the sweet scent 



of Roses, Peas, etc.; and the 



powerful scents emitted by 



such flowers as the Jasmine, 



J\ Tobacco, and Crinum, as 



"^^1 evening comes on, tend to 



Gfuide the nocturnal moths 



to them. 



Sometimes the odours 



used to attract insects (flies) 



are the reverse of pleasant 



to us. As an instance tlic Nux-vomica tree may be mentioned, 



or Aristolochia rjif/autea {Kan. liatkoli hfivu). 



Scentless flowers usually have some equivalent form of attrac- 

 tion, such as gaudy colours, abundance of pollen, or the grou})- 

 ing of a iiuiiihcr of small florets; whereas inconspicuous flowers 

 (Viohit) arc often endowed with a particularly strong smell. 



Fig. 255. 



Fitr. 25G. 



Figs. 254 — 256 ro])i'csont cymes. 



