204 



ACER 



ACER 



unequal, deeply dentate on the outer margin, entire or 

 nearly so on the inner, glaucous and pubescent beneath; 



getioles densely hairy: fls. rather large, in few-fld. 

 airy corymbs: fr. pendulous on short stalks, with the 

 peduncle scarcely Kin. long; nutlets thick, tomentose; 

 wings spreading at an acute angle. W. China. J.H.S. 

 29:98. R.H. 1912:127. Remarkable for its flaky 

 bark, resembling that of the river birch; hardy at the 

 Arnold Arboretum. 



46. mandshuricum, Maxim. Shrub or small tree: 

 branchlets glabrous: Ifts. oblong or oblong-lanceolate. 

 2-3K m - long, short-stalked, acuminate, remotely and 

 obtusely serrate, glabrous, glaucous beneath; petioles 

 glabrous, red, 2-4 in. long: fls. in few-fld. glabrous 

 corymbs: fr. on stalks K-%in. long; nutlets thick, 

 glabrous ; wings spreading at obtuse angles. Manchuria. 

 Graceful maple, hardy at the Arnold Arboretum; the 

 red color of the slender If.-stalks contrasts well with 

 the dark green foliage. 



Section NEGUNDO. 



47. HSnryi, Pax. Tree, to 30 ft.: branchlets slightly 

 pubescent: Ifts. 3, elliptic, 2-3 K m - long, stalked, 

 acuminate, entire or coarsely serrate, pale green and 

 pubescent beneath; petioles finely puberulous: fls. 

 nearly sessile, small, greenish in slender pendulous 

 pubescent racemes, lateral, without Ivs. or with small 

 Ivs. at the base: fr. glabrous, short-pediceled, in 

 pendulous racemes with the stalk 4-7 in. long; wings 

 upright or slightly spreading. Cent. China. J.H.S. 

 29:93, 96 (as A. sutchuenense). Hardy at the Arnold 

 Arboretum. It has been concluded that this and the 

 following species which have been hitherto referred to 

 the preceding section are more closely related to A. 

 Negundo and therefore better transferred to this section. 



48. cissifdlium, Koch (Negundo cissifdlium, Sieb. & 

 Zucc. Crula cissifdlia, Nieuwl.). Small tree: Ifts. 3, 

 stalked, ovate or elliptic, acuminate, coarsely serrate, 

 sparingly ciliate, 2-3 K in. long, light green beneath and 

 glabrous, or nearly so: racemes slender, many-fld., pu- 



100 Acer nikoense. ( X }-i) 



bescent; pedicels less than J^in. long; sepals and petals 

 4, small: fr. in pendulous racemes; wings slightly 

 spreading. Japan. S.I.F. 2:41. Handsome, round- 

 headed tree, with slender, spreading branches and 

 graceful bright green foliage, turning orange-yellow 

 and scarlet in autumn; hardy at the Arnold Arboretum. 



49. Negundo, Linn. (Negundo fraxinifblium, Nutt. 

 N. aceroides, Mcench. Rulac Negtindo, Hitchc.). 

 ASH-LEAVED MAPLE. Box 

 ELDER. Fig. 101. Large 

 tree, 70 ft.: Ivs. pinnate; 

 Ifts. 3-5, ovate or oblong- 

 lanceolate, coarsely ser- 

 rate or 3-lobed, mostly 

 glabroys, 2-5 in. long: fls. 

 before the Ivs.; staminate 

 fls. in pendulous corymbs, 

 pistillate fls. in pendulous 

 racemes. E. N. Amer. 

 S.S. 2:96. Michx. Hist. 

 Arb. 2:18. H.T. 336 

 Large, rapid-growing tree 

 of spreading habit, thriv- 

 ing best in moist and rich 

 soil. Much prized in the 

 W., where it withstands cold and 

 dryness. Largely used for shelter- 

 belts and for planting timber- 

 claims. Var. calif6rnicum, Sarg. 

 (A. calif 6rnicum, Dietr. Negundo 

 calif drnicum, Torr. & Gray). 

 Branches pubescent when young: 

 Ifts. 3, of firmer texture, densely 

 pubescent beneath: fr. not con- 

 stricted at the base. W. N. Amer. 

 S.S. 2:97. Nutt. N. Amer. Sylv. 

 2 : 72. Var. pseudo-calif ornicum , 

 Schwerin (A. calif drnicum, Hort. 

 A. Negundo var. californicum, 

 Kirchn.). Branches green, bloomy; 

 of vigorous growth. Var. viola- 

 ceum, Kirchn. (A. Icalifornicum, 

 Hort.). A vigorously growing 

 form : branches purplish with 

 glaucous bloom or finely pubes- 

 cent when young. Var. argenteo- 

 variegatum, Bonamy. Lvs. with 

 broad white margin. Probably 

 the most effective of all variegated hardy trees. F.S. 

 17:1781. Gn. 68, p. 402 (habit). G. 2:37; 11:97 

 (habit). Var. aureo-variegatum, Booth (var. aureo- 

 macul&tum, Schwerin). Lvs. spotted with yellow. 

 Var. aureo-marginatum, Dieck. Lvs. with yellow mar- 

 gin. Var. auratum, Spaeth (var. califdrnicum aureum, 

 Hort.). Lvs. yellow. R.B. 1906:197. Var. crispum, G. 

 Don. Lfts. curled. These horticultural varieties may 

 be grafted on common box elder seedlings. Box elder 

 also grows from hardwood cuttings, like the grape. 

 Two new forms have been recently described as new 

 species by Britton: A. interior, distributed from Al- 

 berta and Mont, to Ariz, and New Mex. (B.T. 655), 

 and A. Kingii (B.T. 656), from Utah; they are closely 

 allied to var. californicum, but differ in their glabrous 

 foliage; in the first the wings of the samara are adnate 

 to the nutlet only to or above the middle; in the sec- 

 ond the wings reach the point of union of the nutlets. 



A. acumindtum, Wall. (A. caudatum, Brandis, not Wall. A. 

 sterculiaceum, Koch, not Wall.). Allied to A. argutum. Tree: Ivs. 

 3-lobed, 3^4 Ji in. long, glabrous and light green beneath; lobes 

 long-acuminate, and doubly serrate: wings of fr. spreading at a 

 right angle. Himalayas. G.C. II. 15:364 (as A. caudatum). 

 Tender at the Arnold Arboretum. A. ambtffuum, Dippel. Allied 

 to A. pictum. Lvs. pilose beneath : fls. and fr. unknown. Doubtful 

 species of unknown origin. A. dmplum, Rehd. Allied to A. longipes. 

 Tree, to 35 ft.: Ivs. 5-lobed, 4-7 in. broad, glabrous: corymb nearly 

 sessile, 5-6 in. across. Cent. China. A. barbintrve, Maxim. 

 Allied to A. argutum. Shrubby tree: Ivs. 5-lobed, coarsely serrate: 

 pistillate racemes usually 7-fld.: fr. larger. Manchuria. S.T.S. 



Raceme of young 

 fruit of box elder. 

 Acer Negundo. (Nat. 

 size) 



