SAPINDACEA. 113 
SILVA OF NORTH AMERICA. 
San Francisco to about latitude 35°, and in high cafions on the western slopes of the San Bernardino 
Mountains. The California Negundo, which is a spreading tree fifty or sixty feet in height, may be 
distinguished by the bark which is darker than that of the eastern tree, by the thick tomentum of the 
winter-buds, by the short pale persistent pubescence of the branchlets and ripe fruit, and by the con- 
stantly trifoliate leaves with larger more coarsely serrate and more frequently lobed leaflets densely 
coated, even at maturity, on the lower surface with pale pubescence. 
The wood of Acer Negundo is light, soft, close-grained, but not very strong ; it is creamy white, 
with thick, hardly distinguishable sapwood, and contains numerous medullary rays. The specific gravity 
of the absolutely dry wood is 0.4328, a cubic foot weighing 26.97 pounds. The specific gravity of the 
wood of a tree grown in Contra Costa County, California, is 0.4821, a cubic foot weighing 30.04 pounds. 
The wood of the Box Elder is occasionally manufactured into cheap furniture, and is sometimes used for 
the interior finish of houses, for wooden ware, cooperage, and paper pulp. Small quantities of maple- 
sugar are occasionally made from this tree.’ 
Acer Negundo was one of the first North American trees known in Europe; Ray first described it 
in the Mstoria Plantarum,’ published in 1688,’ from plants cultivated by Bishop Compton* in his 
garden at. Fulham near London. It was discovered in California in the neighborhood of Monterey by 
David Douglas. 
The rapid growth made by the Box Elder in good soil, its hardiness, and the cheerful color of its 
graceful foliage have always made it a favorite tree in gardens, although it is not long-lived or very 
stately or handsome in old age; and in the United States it has been planted in great numbers of late 
years, especially in the naturally treeless central part of the continent, where it supports better than many 
other trees the severe climatic changes and the deficiency of moisture. Many varieties® have appeared 
in nurseries, and one of them, producing leaves marked with broad blotches of pure white, is now a pop- 
ular garden-plant in most European countries. 
1 Professor J. B. Harrington (Trans. Roy. Soc. Canada, v. 3, 
1887) found that the average yield of sugar for a number of trees 
was 2.50 per cent. 
2 Arbor exotica foliis Fraxini instar pinnatis, et serratis, Negundo 
perperam credita, 11. 1798. 
Acer maximum foliis trifidis et quinquifidis, Virginianum, Plukenet, 
Phyt. t. 123, £. 4, 5 ; Alm. Bot. 7. — Boerhaave, Hort. Lugd. Bat. ii. 
234. — Duhamel, Traité des Arbres, i. 28. 
Acer foliis compositis, Linneus, Hort. Cliff. 144. — Royen, Fi. 
Leyd. Prodr. 460.— Clayton, Fv. Virgin. 154. The word Negundo, 
which appears to have been first used by Ray, is of unknown mean- 
ing and derivation. 
8 Aiton, Hort. Kew. iii. 436.— Loudon, Arb. Brit. i. 460, t. 
4 See i. 6. 
5 Pax (Engler Bot. Jahrb. vii. 211) distinguishes the varieties 
cultivated in European nurseries as 
Var. vulgare (A. Californicum, A. versicolor, A. violaceum, Hort.). 
a. bicolor (A. aureo-variegatum, and A. argenteo-variegatum, Hort.). 
b. angustissimum (A. crispum, Hort.). 
