MONOCOTYLEDONS 295 



before the Dicotyledons, as a lower class, in spite of the 

 fact that they appear to have originated from the latter. 

 The Dicotyledons are an earlier class, but they have 

 risen higher than the later derived Monocotyledons. 



CLASS MONOCOTYLEDONEAE. 



THE MONOCOTYLEDONS 



533. Cotyledon one; leaves on the stem alternate; 

 vascular bundles in the stem scattered (as seen in cross- 

 section), in the leaf blades parallel ("parallel-veined"); 

 perianth whorls mostly ternate (in 3's). 



534. There are seven or eight types (orders) of Mono- 

 cotyledons. The lowest of these (Alismatales) is rep- 

 resented by the Water Plantain, already described. 

 The others are briefly as follows: 



535. Lilies (Liliales). In a Lily the carpels (mega- 

 sporophylls) have been reduced to three, and these have 

 grown together into a single pistil ("com- 

 pound pistil"), in which each carpel 



retains its ovule-bearing cavity (i.e. the 



pistil is "3-celled"). The stamens (mi- 



crosporophylls) are in two whorls of 



three each: the petals are three; and the 



sepals three. Commonly the perianth is 



relatively large, and the two whorls of 



similar texture. Throughout the flower the members of 



successive whorls are alternate. 



536. The flower structure here reached appears to be 

 typical of the great body of the Monocotyledons; and the 

 structural peculiarities of the following orders are only 

 modifications of those of the Lilies. 



537. Calla Lilies (Arales). In the Calla Lilies the 

 individual flowers are small, and massed on a thick 



