260 



TEXTBOOK OF BOTANY 



b 



bean, contains both stamens and pistil. A flower that con- 

 tains both stamens and pistil is often called a perfect flower. 

 This is a convenient term, but one that is likely to give a 

 wrong impression. For the work that they have to do, the 

 separate staminate and pistillate flowers of the cucumber 

 are just as perfect as is the " perfect" flower of the bean. 

 In the case of plants with separate 

 pistillate and staminate flowers, the 

 two kinds may be borne on two dis- 

 tinct plants. This is the case in the 

 willows, the poplars, and the hop. 

 But many plants with separate stami- 

 nate and pistillate flowers, among 

 them the corn, the cucumber, and 

 the oak, bear both kinds of flowers 

 on the same plant. 



271. Sepals and Petals. The 

 primitive angiosperm flowers prob- 

 ably, much like the pine cone, had 

 only stamens or pistils, and nothing 

 FIG. 151. The floral that corresponded to sepals or petals, 

 structure of the Jack-in- There are still many angiosperms 

 the-pulpit; a, the s bathe, a .., Ljn o i, r 



large leaf which encloses th SUch naked flowers ' Sudl > f r 

 the flower cluster; b, the instance, is the Jack-in-the-pulpit 

 spadix or stalk which bears (pj g- x 5 x ) w hose flowers are crowded 



j.1. _ flowprs * 



it r r>u. together on a common stalk. The 

 pistillate flowers of the birch are also 

 naked. From the primitive condi- 

 tion of naked flowers there are several steps in advance. 

 Some flowers have sepals only ; these may be green or 

 greenish as in the flowers of the oak and the elm, or white 

 as in the common anemone, or colored as in the hepatica. 

 Some flowers, like the lily (Fig. 153), have sepals and 

 petals that are almost exactly alike; but most showy 

 flowers such as the violet, the bean, the sweet pea, and 



the numerous 

 staminate flowers at c, pis- 

 tillate flowers at d. 



