COMPOSITOUS AND GRASS FLOWERS 



151 



developed into a long, strap-like 



or tubular part and the corolla of 



those at the center may be but a 



short tube. The head then has 



the appearance of being one flower 



with a border of petals. Of such 



is the sunflower (Fig. 188), aster 



(Fig. 252), bachelor's button or 



cornflower (Fig. 256). These long 



corolla-limbs are called rays. In 



some cultivated composites, all 



the florets may develop rays, as in 



the dahlia (Figs. 257, 258) and 



chrysanthemum. In some species, 



as dandelion, all the florets natu- 

 rally have rays. Syngenesious 



arrangement- of anthers is the 



most characteristic single feature 

 of the composites. 



306. Grass Flow- 

 ers. The flowers 

 of grasses are too 

 difficult for the be- 

 ginner, but if the 

 pupil wishes to un- 

 derstand them he 

 may begin with 



wheat or rye or barley, which are members 

 of the Grass family. The "head" or spike of 

 wheat is made up of flowers and bracts. The 

 flowers are in little clusters or spikelets (often 

 called ' 'breasts" by farmers). One of the 



260. Flower of rye/ spikelets is shown at fe, in Fig. 259. Each 



o, stigma; 6, 6, 6, 



stamens; c, paiet; spikelet contains from 1 to 4 flowers or florets, 

 giume.En!arged! The structure of the flower is similar to that 



259. Spikes and flowers of wheat, 

 a. beardless wheat; d, bearded 

 wheat; 6, spikelet in bloom; c, 

 grain; e, single spikelet on a 

 mature head. The beards in d 

 are awns 'on the flowering 

 glumes. 



