CLASSIFICATION OF ANGIOSPERMS. 355 



(Cornns florida) are subtended by four large, petal-like, white, or 

 pinkish bracts. 



The bark of Cornus florida, a shrub or small tree growing in 

 the United States, contains a bitter principle, cornin ; and a small 

 quantity of gallic and tannic acids. 



Auciiha japonica, a plant indigenous to the Himalayas, China 

 and Japan and extensively cultivated on account of its crimson 

 berries, contains a glucoside aucubin. It is found in the different 

 varieties and varies in amount from 0.31 to 1.96 per cent. 



METACHLAMYDE.E OR SYMPETAL^. 



This is the highest group of plants and is marked by the fol- 

 lowing characters : The corolla is sympetalous ; the flowers are 

 mostly perigynous or epigynous and both the corolla and stamens 

 are borne on the perianth tube. The number of parts is definite, 

 there being 5 sepals, 5 petals, 5 or 10 stamens and 2 or 5 carpels. 

 This sub-class includes but six orders, to which, however, belong 

 a large number of medicinal and economic plants. 



I. ORDER ERICALES. 



The plants of this order are distinguished by the fact that the 

 stamens are mostly free from the perianth tube. 



a. PYROLACE^. The plants are small, mostly evergreen 

 perennials, and are represented in the United States by several 

 genera. 



Chimaphila nmbellata (Prince's pine or Pipsissewa) is a small 

 trailing or creeping plant producing distinct flower- and leaf- 

 branches. The leaves are official (p. 603).' The flowers are in 

 small corymbs and the petals are white or pinkish. In Chima- 

 phila macidata the leaves are lanceolate, mottled with white along 

 the veins and the flowers are considerably larger. 



With the P}Tolacese are sometimes grouped the saprophytic 

 plants of the genus Monotropa. There are two representatives of 

 this genus which are common in the United States, namely, Indian 

 pipe {Monotropa uniHora) and false beech-drops {M. Hypopitys) 

 The latter contains a glucoside or an ester of methyl salicylate, 

 and a ferment gaultherase. 



