24 SILVA OF NORTH AMERICA. ANACARDIACEZ. 
and is often flattened and slightly gibbous, and is tipped with the dark remnants of the styles. The 
outer coat is thin, more or less striated at maturity, ivory white or white tinged with yellow, and very 
lustrous ; the stone is conspicuously grooved, thin, rather membranaceous than coriaceous, and, like the 
testa of the seed, pale yellow. 
Ithus Vernix is common in all the region between northern New England and northern Georgia 
and Alabama, and extends westward to northern Minnesota and to Arkansas and western Louisiana, 
inhabiting wet swamps often inundated during a portion of the year. 
The wood of Rhus Vernix is light, soft, and coarse-grained, with three or four rows of large open 
ducts clearly defining the layers of annual growth, and thin, very obscure medullary rays. It is light 
yellow streaked with brown, the sapwood being lighter colored, and when absolutely dry has a specific 
gravity of 0.4382, a cubic foot weighing 27.31 pounds. 
Rhus Vernix is one of the most dangerous plants of the North American flora. 
the effluvium from the flowers possess the properties found in those of Rhus Metopium and Rhus 
Toxicodendron, and to most persons are even more injurious.' The extreme brilliancy and beauty in 
autumn of the foliage of the Poison Dogwood,’ as this plant is almost invariably called in the northern 
states, allure many people ignorant of its true character to gather and handle it, and cases of serious 
poisoning are a common consequence. It contains the volatile principle toxicodendric acid found in 
the allied Rhus Toxicodendron, and possesses properties of as great medicinal value as that plant.’ 
An infusion of the young branches and leaves is employed in homeopathic practice ;* and the juice can 
be used as a black lustrous durable varnish very similar to that furnished by the Japanese Lacquer- 
The juices and 
tree.® 
Rhus Vernix was first described by Plukenet in the Phytographia® published in 1691, and was 
cultivated in the Physic Garden at Chelsea’ in England as early as 1713.8 
2 Kalm, Travels, English ed. i. 77.— Cutler, Mem. Am. Acad. i. 
428. — B.S. Barton, Coll. i. 24.— Bigelow, Med. Bot. i. 96, t. 10. — 
U. S. Dispens. ed. 14, 908. — Nat. Dispens. ed. 2, 1464. — James 
C. White, Dermatitis Venenata, 31. 
2 Rhus Verniz is also known in some parts of the country as 
Poison Elder and as Poison-tree. 
8 Lawrence Johnson, Jfan. Med. Bot. N. A. 118. 
* Millspaugh, Am. Med. Pl. in Homeopathic Remedies, i. 37, t. 37. 
5 Bigelow, l. c. 
® Arbor Americanus alatis foliis, succo lacteo venenata, Phyt. t. 
145, f. 1; Alm. Bot. 45. 
Rhus Americanum rachi (cui adnectuntur folia) rubra, folio lato 
ulrinque glabro non serrato, pistachie simili, Boerhaave, Hort. Lugd. 
Bat. ii. 229. — Colden, Cat. Pl. Novebor. 64. 
Arbor cujus lignum venenatum, Paul Dudley, Phil. Trans. xxxi. 
145. — Sherard, Phil. Trans. xxxi. 147. 
Toxicodendron Carolinianum, foliis pinnatis, floribus minimis her- 
baceis, Miller, Dict. No. 3. 
Toxicodendron foliis alatis, fructu rhomboideo, Dillenius, Hort. 
Elth. 390, t. 292, £. 377. 
Rhus foliis pinnatis integerrimis, Linneus, Hort. Cliff. 110; Hort. 
Ups. 68 ; Mat. Med. 50. — Royen, Fl. Leyd. Prodr. 244. — Clayton, 
Fl. Virgin. 148. 
7 Aiton, Hort. Kew. i. 366. — Loudon, Arb. Brit. ii. 552, £. 226. 
8 The confusion which has long existed with reference to the 
name of this plant was due to the fact that Linneus, misled by 
the similarity of the Japanese Varnish-tree, united this with the 
American Poison Sumach, calling the species thus enlarged Rhus 
Verniz, the name, of course, relating to the properties of the 
Japanese and not of the American plant. De Candolle found that 
the two plants were distinct and made new names for them both, 
dropping entirely the Linnean specific name Verniz. This, how- 
ever, is the oldest name, and clearly belongs to the American and 
not to the Japanese plant, as Linnzus’s description in the Hortus 
Cliffortianus, as well as that in the Species Plantarum, makes it 
clear that he considered the American plant as the type of his 
species to which he referred the Japanese plant of Kaempfer. (See 
in this connection discussions upon the differences in the two trees 
by Abbé Mazeas, Philip Miller, and John Ellis. Phil. Trans. xlix. 
157, 161, 866.) 
