•204 



ACER 



ACER 



unequal, dcoply dontato on tlio outer margin, entire or 

 nearly so on the inner, plaucous and pulieseent beneath; 

 petioles densely hair\': Is. ratlier large, in few-fid. 

 luiiry corymbs: fr. pen<lulous on siiort stalks, with the 

 pixlunele seareely 'jin. long; nutlets thiek, fomentose; 

 winss spreading at an acute angle. ^^■. China. — J. U.S. 

 •J'.):S1S. H.H. l'.)r2:rJ7.— Remarkable for its flaky 

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

 Arnold .Vrboretiiin. 



4t). mandshfiricum, Maxim. Shrub or small tree: 

 branchlets glabrous: Ifts. oblong or oblong-lanceolate, 

 2-3 '2 '"■ long, short-stalked, acuminate, remotely and 

 obtusely serrate, glabrous, glaucous beneath; petioles 

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

 corymbs: fr. on stalks 32-'4'"- long; nutlets thick, 

 glabrous; wings spreading at obtuse angles. Manchuria. 

 — Graceful ma)ile, hardy at the Arnold .Xrboretum; the 

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

 the dark green fohage. 



Section Negtjndo. 



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

 pubescent: Ifts. 3, elliptic, 2-314 in. long, stalked, 

 acuminate, entire or coarsely serrate, pale green and 

 pubescent beneath; jjetioles finely puberulous: fls. 

 nearly sessile, small, greenish in slender pendulous 

 pubescent racemes, 'lateral, without Ivs. or with small 

 Ivs. at the biisc: fr. glabrous, short-pediccled, in 

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

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

 29:93, 9G (as ,4. sulchuenense) . — Hardy at the Arnold 

 Arboretum. — It has been concluded that this and the 

 following species which have been hitherto referred to 

 the precwling section are more closely related to A. 

 Xegumld and therefore better transferred to this section. 



48. cissifolium, Koch {Negundo cisaifblium, Sieb. <fe 

 Zucc. Criila cissijblia, Nieuwl.). Small tree: Ifts. 3, 

 stalked, ovate or elliptic, acuminate, coarsely serrate, 

 sparingly ciliato, 2-3' 2 in. long, light green beneath and 

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



100 Acer nikoense. ( X ]4) 



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

 4, small: fr. in jK-ndulous racemes; wings slightly 

 sprea<ling. Japan. S.l.F. 2:11. — Handsome, round- 

 headed tree, with slender, s|)reading branches and 

 graceful bright green foliage, turning orange-yellow 

 and scarlet in aiitunm; hardy at the Arnoki .Vrboretum. 



49. Negundo, Linn. {Negundo fraxinifdlium, Nutt. 

 A', accrdiilcs, Mu'nch. liulac Negundo, Uitchc). 

 Ash-leaved M.\ple. Box 

 Eldek. Fig. 101. Large 

 tree, 70 ft.: Ivs. pinnate; 

 Ifts. 3-.'j, ovate or oblong- 

 lanceolate, coarsely ser- 

 rate or 3-lobiMl, mostly 

 glabrous, 2~r> in. long: fls. 

 before the Ivs,; staminate 

 fls. in iHMuhdous i^orymbs, 

 pistillate lis. in i)endulous 

 racemes. E. N. Amcr. 

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

 Arb. 2: IS. H.T. 336.— 

 Large, rapid-growing tree 

 of sjjreading haliit, thriv- 

 ing best in moist and rich 

 soil. Much prized in the 

 W., where it withstantls cold and 

 dryness. Largely used for shelter- 

 belts and for jjlanting timber- 

 claims. Var. californicum, Sarg. 

 {A. calif dndcum, 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. pse&do-califomicum, 

 Schwerin (A. calif I'lmieum, Hort. 

 A. Negundo var. calif drnicum , 

 Kirchn.). Branches green, bloomy; 

 of vigorous growth. Var. viola- 

 ceum, Kirchn. (.4. ]calif6rnicum, 

 Hort.). A vigorously growing 

 form: branches purplish with 

 glaucous bloom or finely pubes- 

 cent, when young. Var. argenteo- 

 variegatum, Bonaniy. Lvs. with 

 broad white margin. Probably 

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

 17:1781. Gn. 08, p. 402 (habit). G. 2:37; 11:97 

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

 7nacul()lum, Schwerin). Lvs. spotted with yellow. 

 Var. a&reo-marginatum, Dieck. Lvs. with yellow mar- 

 gin. Var. auratum, ■Spaeth (var. califdrnicum aiireum, 

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

 Don. Lfts. curled. The.se 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 bv Britton: A. interior, distributed from Al- 

 berta and Mont, to Ariz, and New Mex. (B.T. 65.5), 

 and A. Kingii (B.T. 6.56), 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. acuminatum. Wall. (A. caudatum. Brandis, not Wall. A. 

 sterculiareum, Koch, nut Wall.). Allied to A. argutum. Tree: lvs. 

 3-lobed. 3-4)2 in. long, Elabrous and light green beneath; lobea 

 long-acuininate. and doulily serrate: wings of fr. spreading at a 

 right angle. Himalayas. G.C, II. 15:.'Sli4 (as A. caudatum). 

 Tender at the Arnold Arboretum. — A. amMouum. Dippel. Allied 

 to A. pietuin. I.vs. pilose beneath: fls. and fr. unknown. Doubtful 

 species of unknown origin. — A. dmplum, Kehd. .Allied to A. longipes. 

 Tree, to 3.5 ft.: lvs. .i-lobcd, 4-7 in. broad, glabrous: corymb nearly 

 sessile, 5-0 in. across. Cent. China. — A. barbinlrve, Maxim. 

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

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



101. Raceme of young 

 fruit of box elder. — 

 Acer Negundo. (Nat. 

 sizej 



