LEAVES, BUDS AND FLOWERS 



91 



and many other plants have no stamens, while other 

 flowers of the same species have no pistils (153). In 

 many varieties of the American plums {Prunus araeri- 

 cana, P. angustifolia, P. hortulana) the pistil is often 

 wanting. 



147. Composite flowers ^ are made of several individual 

 flowers in the same flower-head. The sunflower (Fig. 

 50) is a familiar example of a composite flower. One of 

 the separate flowers is shown in Fig. 51. At the outer 

 edge of the flower-head, is a row of individual flowers, 

 each of which has a long, yellow, 

 petal-like appendage (Fig. 52), 

 called a ray. The flowers bear- 

 ing rays are called ray-flowers. 

 Some composite flowers as of 

 the tansy (Tanacetum vulgare) 

 are without ray-flowers. 



148. The flowers of the grass 



family (Gramineae) to which the 



cereals belong, as well as corn, 



sorghum, sugar cane and the 



like, are quite different from ^'g- 52. - Ray-flower of 

 , » T same. 



those of most other plants. In 



this family, the flowers are arranged in little groups, 



each of which is called a spikelet. What we call a 



head of wheat is made up of a number of spikelets, 



one of which is shown in Fig. 53. Fig. 54 shows the 



spikelet dissected. The two scale-like parts at the base, 



g, g, are called glumes. Above these on either side is 



another scale, flowering glume or lemma, tipped with a 



bristle (the awn or beard). Wrapped within this is 



1 The plants having composite flowers form an extensive 

 family in botany, called Compositae. 



Fig. 51. 



Fig. 52. 



Fig. 51. — Enlarged floret 

 of sunflower. 



