CHAP. XXXVIII. ANACARDIA CEM. tflTUS. 555 



tluced into England in 1697, and is occasionally to be met with in collections. 

 There are good plants of both the species and the variety in the arboretum of 

 Messrs. Loddiges. Plants of the species, in London, are )s. 6d. each, and 

 seeds Is. an ounce; at New York, 37| cents a plant. 



„* 1 10. R. radi v cans L. The rootmg-branched Rhus, or Sumach ; or 



Poison Oak. 



Identification. Lin. Spec, 381.; Dec. Prod., 2. p. 69. ; Don's Mill, 2. p. 71. 



Synonymes. R. Toxicodendron var. « Michx. Fl. Bor. Amer., 1. p. 185. ; and R. T. var. (3 Torrey 



Fl. U. S., 1. p. 322. 

 Engravings. Big. Med. Bot., t. 42. ; and our fig. 230. 



Spec. Char. ySfc. Leaf of one pair of leaflets and an odd one, the odd one 

 upon a petiole; all glabrous and entire. (Dec. Prod., ii. p. 69.) A native of 

 North America. De Candolle has characterised three forms of this species 

 as follows : — 



A R. r. 1 vulgaris. — Stem climbing by means of roots emitted from it ; 



leaflets large, ovate. R. Toxicodendron vulgare Ph. Fl. Amer. 



Sept., i. p. 205. ; Bot. Mag., t. 1806. ; Toxicodendron vulgare, and 



T. volubile Mill. Diet. This often poisons upon mere touching. 



1 R. r. 2 volubilis. — The stem climbing, scarcely emitting roots ; the 



leaflets large and ovate. Toxicodendron volubile Mill. Diet. 

 .1 R. r. 3 microcdrpa. — Leaflets oblong-oval with a tapered long point ; the 

 fruit much smaller than that of the other forms. R. Toxicodendron 

 microcarpon Ph. Fl. Amer. Sept., i. p. 205. There is a figure of this 

 in Dill. Elth., t. 291. fig. 375. A plant of this variety in the garden 

 of the London Horticultural Society was, in 1834, 4 ft. high, after 

 having been 8 years planted. 

 Description, fyc. This species,in America, has 

 a low shrubby stem, and forms a bush from 2 ft. 

 to 3 ft. in height, whence shoots proceed near 

 the bottom to the distance of 20 ft. or 30 ft. 

 on each side, rooting at the joints, and com- 

 pletely occupying the surface of the ground. 

 Placed near a wall or a tree, the shoots climb 

 up, and root into the joints of the wall, or 

 into the furrows of the bark of the tree, if the & 

 latter should be old. It is a native of many 

 parts of North America, from Canada to 

 Georgia; sometimes covering the surface of 

 the ground to a great extent ; and at other times climbing to the top of the 

 highest trees, and penetrating the bark with its fibrous roots. When the stem 

 is cut, it emits a pale brown sap of a disagreeable scent; and staining so pow- 

 erfully, that letters or marks made upon linen with it cannot be obliterated, 

 but grow blacker the more the linen is washed, not being acted upon by com- 

 mon chemical agents. {Churchill 's Medical Botany, vol. ii.) In Bigelow's 

 Medical Botany, it is stated, that the plant is as common in the woods of 

 America as the ivy is in the woods of Europe; " and the terrible effects of its 

 poison are so frequent, that there seems to be no doubt on the subject. An 

 American young man, who was cutting wood, had his feet, hands, and arms so 

 dreadfully blistered by an unwary approach to this plant, that he could not 

 work for some days." Kalm relates that the plant is poisonous to some 

 persons, but less so to others, and that the same thing takes place with respect 

 to it as with R. venenata. (See p. 553.) He mentions the case of two sisters, 

 one of whom could manage a plant of R. radicans without being affected by 

 its venom ; whilst the other felt its exhalations as soon as she came within a 

 yard of it, or even when she stood to windward of it at a still greater dis- 

 tance. Kalm says that the poison had not the least effect upon himself, 

 though he tried it in various ways, and once squirted the juice into his eye ; 

 but that, on another person's hand, which he had covered very thickly with 

 it, the skin, a few hours afterwards, became as hard as a piece of tanned 



