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 ameri- 

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

 wanting. 



147. Composite flowers l 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 FlG - 52 - 

 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 i? 

 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. 



- Ray-flower of 

 same. 



