644 A TEXT-BOOK OF BOTANY. 



I. ORDER ERICALES. 



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

 stamens are mostly free from the perianth tube. 



a. PIROLACE^E. The plants are small, mostly evergreen 

 perennials, and are represented in the United States by several 

 genera. 



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

 trailing or creeping plant producing distinct flower- and leaf- 

 branches. The 'leaves are used in medicine. The flowers are in 

 small corymbs and the petals are white or pinkish. In Chimaphila 

 maculata the leaves are lanceolate, mottled with white along the 

 veins and the flowers are considerably larger. 



With the Pirolaceae 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 uniflora) and false beech-drops (M. Hyp opitys). 

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

 a ferment gaultherase (Fig. 349). 



b. ERICACEAE OR HEATH FAMILY. This is a large 

 family and the plants are widely distributed, especially in the 

 northern mountainous parts of both the Eastern and Western Con- 

 tinents. They vary from perennial herbs to trees. The flowers 

 are usually regular, the stamens being mostly 2-spurred (Fig. 

 221, S), and the fruit is either a superior or inferior drupe or 

 berry (Fig. 280, H). 



Arctostaphylos Uva-Ursi is a low branching shrub which trails 

 or spreads on the ground. The leaves are used in medicine (Fig. 

 355). The flowers are small, white or pink, few and in short 

 racemes. The fruit is a red, globular drupe. 



Trailing arbutus (Epigcca re pens) is a trailing, shrubby, hairy 

 plant with broadly elliptical or ovate, coriaceous, evergreen leaves 

 and white or rose-colored, fragrant flowers which are either per- 

 fect, with styles and filaments of varying length, or dioecious. The 

 leaves contain similar constituents to those in Uva-Ursi and 

 Chimaphila (Fig. 353). 



The leaves of wintergreen (Gaultheria procumbens) are the 

 source of true oil of wintergreen, which consists almost entirely 



