THE HAMILTON ASSOCIATION. 121 



Rhus Semi-alata, a native of China and Japan, yields a gall 

 largely used, especially by the Chinese, in dyeing their famous yel- 

 low silks. It is also highly esteemed by them as an astringent 

 medicine. 



Of the native species of Rhus I shall speak of eight, and, not 

 to afflict you with their scientific distinctions, I will classify them as 

 poisonous and non-poisonous, confining my botanical descriptions 

 chiefly to the poisonous class, it being most important, to be able 

 clearly to distinguish these from certain non-poisonous plants resem- 

 bling them. The eight species are equally divided, four being in- 

 nocent and four highly noxious. And first let me call attention to 

 the non-poisonous varieties, meaning by this non-poisonous by con- 

 tact with the plant, for, if given internally in large doses, even the 

 innoxious ones act as irritants. 



Rhus Aromatica, fragrant sumach — is a straggling bush with 

 tri-foliate, hairy leaves. The pale-yellow flowers, in clustered spikes 

 hke catkins, precede the leaves, which are sweet-scented when 

 crushed. It extends from Lake Superior westward and southward, 

 in dry, rocky soil, a variety, the Rhus Trilobata of Nuttall, chiefly 

 affecting the Rocky Mountains and Sierra Nevadas. This plant, a 

 a few years ago, had a high reputation among some authorities as 

 an astringent in enuresis, the diarrhoea of children, and the night 

 sweats of consumption, but it has now fallen into disuse to a very 

 great extent. 



Rhus Glabra^ variously known as sleek, smooth, Pennsylvania 

 and upland sumach is found over the greater part of North America, 

 south of the Arctic Circle. It is a short two to twelve feet high, 

 with straggling branches, covered with smooth, light gray or some- 

 what reddish bark. The compound leaves, consisting of eleven to 

 thirty-one leaflets, whitened beneath, in autumn change to a beauti- 

 ful red. Growing along fences, borders of woods, and in rocky 

 fields, its flowers open about July, and the fruit, often eaten by the 

 country people, ripens in early fall. Excrescences produced on the 

 under side of the leaves have been used as a substitute for the 

 officinal galls obtained from the oak, Quercus Infectoria. Like galls, 

 these excrescences are due to puncture of the young shoots by a 

 hymenopterous insect to deposit its eggs. This irritates the part 

 and a tumor arises, the result of morbid growth. The eggs enlarge 

 with this growth and are converted into larvae, which feed on the 



