572 NOTES ON THE GENUS RHUS. [Jan. 



The genus belongs to the natural order Jnacardiacew, the Cashew 

 JVnf family, an order of great botanical as well as some commercial 

 and medicinal interest. The flowers in some of the species of JRIms 

 are hermaphrodite, while in others such as JR. toxicodendron they are 

 unisexual or hermaphrodite, or both conditions may be concurrent 

 on the same plant or even in the same spike of flowers. The 

 reason given by botanists for this Deculiarity is that the reproductive 

 organs of either sex are liable to fail in development by the process 

 of abortion — a reason which may well enough serve our present 

 purpose, but which merely points at the same time to the result of 

 an undefined cause. The following are a few of the most remarkable 

 species : — 



li. coriaria is a small tree growing about 10 feet high, with 

 elegant pinnate leaves. It is said to supply the bark with which 

 Turkey leather is tanned. It is greatly in repute as a tonic and 

 cooling agent in decoction, in the south and east of Europe, and the 

 peasants of Podolia, the Ukraine, and Eussia generally, use it in 

 decoction with Genista tinctoria as a preventive of hydrophobia. In 

 Aleppo the seeds are in constant use as a tonic. The tree is 

 a native of the South of Europe generally, and is hardy in this 

 country. 



R. typhina is a tree of larger growth than the preceding, and has 

 a wide range of habitat in North America, where it is commonly 

 called the Virginian sumach, and sometimes also the Star/'s-horn 

 sumach. It has a long list of uses in the arts : the wood and bark 

 are both equally useful in tanning, especially white glove leather ; 

 it is used by dyers to give tone to black, green, and yellow colours, 

 and treated with alum, the ripe berries make an excellent dye for 

 hats. From incisions made in the bark, there exudes a milky juice 

 which when dried forms the basis of a varnish said to be equal to 

 the best Chinese, and it is further said that the flowers yield more 

 honey, and that bees are fonder of it than of any other flowers. 



B. toxicodendron (the poison oak). This a less reputable tree, or 

 rather shrub — for it never assumes arboreal proj)ortions — than either 

 of the preceding. It is a native of North America, where it is known 

 by the significant common name above given. Although there is 

 little doubt the plant is poisonous in a high degree, yet there are 

 those on whom it appears to be quite innocuous ; some have suffered 

 severely from any lengthened exposure to the exhalations from its 

 leaves, while others have felt no ill effects from similar experience 

 in precisely the same circumstances. It has one very extraordinary 

 peculiarity : the sap, if used to mark linen, makes an indelible stain 

 which the more it is washed becomes the deeper. The gum or hardened 

 juice, it is said, has been applied successfully in cases of paralysis. 



