138 



PARTICULAR FORMS OF FLOWERS 



pollination. Observe how a bee forces his head into the 



closed throat of the toad-flax. 



275. LILY FLOWERS. In plants of the lily 

 family (Liliaceae) the flowers are typically 

 3-merous, having three sepals, three petals, 

 six stamens and a 3-carpelled pistil. The 

 parts in the different series are distinct from 

 each other (excepting the carpels,) arid mostly 

 free from other series. The sepals and petals 

 are so much alike that they are distinguished 

 chiefly by position, and for this reason the 

 words calyx and corolla are not used, but 

 the floral envelopes are called the perianth 

 and the parts are segments. Flowers of lilies 

 and trilliums (Fig. 221) answer these details. 

 Not all flowers in the lily family answer in all 

 ways to this description. The term perianth 

 is used in other plants than the Liliaceas. 

 990 276. PAPILIONACEOUS FLOWERS. 111 the 



Personate flowers pea and bean tribes the flower has a special 



of snapdragon. orm (Pig-. 222) . Tll6 



calyx is a shallow 5 -toothed tube. 

 The corolla is composed of four 

 pieces, the large expanded part 

 at the back, known as the stand- 

 ard or banner; the two hooded 

 side pieces, known as the wings ; 

 the single boat -shaped part be- 

 neath the wings, known as the keel. 

 The keel is supposed to represent 

 two united petals, since the calyx 

 and stamens are in 5's or multi- 

 ples of 5; moreover, it is com- 

 posed of two distinct parts in cassia (Fig. 223) and 

 some other plants of the pea family. Flowers of the 



221. Flower of trillium. 



