512 



MANUAL OF POISONOUS PLANTS 



injured by the prickles and spines of the rose which produced inflammation and 

 caused the formation of pus. 



4. Pyriis L. 



Trees or shrubs; simple leaves; flowers in cymose clusters, white or pink; 

 calyx urn-shaped, S-lobed; petals S, short-clawed; stamens usually numerous; 

 styles mostly 5, distinct or united at the base; ovules 2 in each cavity; carpels 

 leathery; fruit a pome. About 37 species of wide distribution, chiefly in the 

 North Temperate region. The following species of the genus are cultivated 

 for their fruits; quince (P. Cydonia), pear (P. communis), Japan or sand pear 

 (P. sinensis'), apple (P. Malus), Old World crab apple (P. baccata), mountain 

 ash (P. americana), ( P. sitchensis P. sambucifolia) , European mountain ash (P. 

 Aucuparia) . 



The fresh bark of the wild mountain ash is used in medicine; it is known 

 to produce irritation of the alimentary mucous membranes, and a reflex nervous 

 irritation. 



Pyrus coronaria L. Wild Crab Apple 



A small tree with petioled or ovate to triangular-ovate leaves, sparingly 

 pubescent beneath; sharply serrate and often lobed; flowers rose-colored, frag- 

 rant; caly:x slightly pubescent; pome fleshy, fragrant, greenish-yellow, acid. 

 Two other species are found in eastern North America, namely, P. angustifolia, 

 with small leaves and few flowers, and P. ioensis, with firm leaves, narrowed at 

 the base, and pubescent calyx, chiefly west in the Mississippi Valley, P. rivularis 

 Dougl., occurs from California to Alaska. 



Distribution. Our Eastern wild crab is found from Ontario to Michigan 

 and South Carolina ; in the west it is replaced by the P. ioensis. 



Poisonous and medicinal properties. All the species of the genus Pyrus 

 contain the glucoside amygdalin, Cj^H^^NO^j^, which is converted by the action 

 of the ferment into hydrocyanic acid. ' The bark also contains citric acid, 

 CjHgOj, and malic acid, C^H^Og, both of which appear in the fruit of the ap- 

 ples. There may be occasionally cases of poisoning where animals are allowed 

 to browse upon the wilting leaves of the apple. 



Fig. 273. Common apple (.Pyrus Mains). The well known cul- 

 tivated apple. (W. S. Dudgeon). 



