440 SAPIXDACE.E. Acer. 



A. leucoderme, Small. Tall shrub or small tree, becoming 25 feet high and 18 inches 

 iu tliaiiietei-, cuumionlv dividing near the base ; bark close and wliite, not exfoliating : twigs 

 dull red, soon becoming gray : leaves rather small as in the last, 3(to somewliat o)-lobeii ; 

 lobes caudate-acuminate, coarsely ami sinuately 1-3-tootlied or undulate; upper surface 

 dark dull green ; lower surface yellowish green (not at all glaucous), velvety-tomentulose 

 and exceedingly soft to the touch ; base subtruucate or sliallowly conlate with a narrow 

 sinus: seminiferous part of tiie key sparingly setulous, at length glabrate ; wings commonly 

 but not always widely divergent, sometimes almost divaricate. — Bull. Torr. Club, xxii. 3G7, 

 xxiv. 64. ^1. Floridanum, var. acuminatum, Trelease, 1. c. 99, t. 11. — Walls of gorges, &.C., 

 North Carolina, Hunter, Small, to Floriila and Louisiana, Hale. 



* * Western species : leaves rather small, fully as broad as long ; lobes coarsely and ob- 

 tusely tootiied or undulate : young branchlets ratlier deep glossy red : calyx tending to 

 persist at tlie base of the young or even mature fruit. 



A. grandidentatum, Nutt. Tall siirub or small tree with trunk seldom over a foot in 

 diameter and brauciies covered with pale thin bark : leaves of rather firm texture, 2 or 3 

 inches in diameter, 3(to somewhat 5)-lobed, above glabrous, often shining, pale green and 

 finely reticulated, below paler (yet not canescent) and covered with a fine tomeutum ; lobes 

 rarely subentire, more often undulate-dentate witli large blunt teeth ; base mostly corchite : 

 filiform pedicels and obtusely 5-toothed campanulate calyx villous : wings 8 to 12 "lines long, 

 somewhat divergent ; the body (at least when young) setulous. — Nutt. in Torr. & Cray, 

 n. i. 247, & Sylv. ii. 82, t. 69 ; Wats. Bot. King Exp. 52 ; Trelease, 1. c. 104, t. 13. A. bar- 

 latum, var. rfvandidentatum, Sargent, Silv. ii. 100, t. 92. — Wooded valleys in the Kockj 

 Mts. from N. Montana, where first coll. by Nuttall, to Arizona and W. Texas. (Nortlieru 

 Mex., Palmer, Hartman.) A geographical species without very strong technical distinctions; 

 rather rare and local. Although scarcely distinct from the Rock Maple of the East this 

 species is by Pax and Wesmael unaccountably referred to another section of the genus. 



§ 5. Negundo, Koch. Flowers strictly dioecious, neither the $ nor 9 with 

 rudimentary organs of the other: disk obsolete ; petals none : stamens 5, episepa- 

 lous ; anthers linear, appendaged or mucronate at the tip : leaves pinnately .')-7 

 (or even 9)-foliolate. — Dendr. i. 543. Negundo, Moench, Meth. 334. Negun- 

 dium, Raf. in Desv. Jour. Bot. ii. 170 (1809). 



A. Negundo, L. (Box Elder.) A widely branched tree 30 to 50 rarely 75 feet in height, 

 seldom more than 2 or 3 feet in diameter: bark light colored, considerablv fissured but of 

 close firm texture : branchlets and young shoots pale green turning brown, glabrous or 

 covered with a very fine close puberulence : leaflets ovate-lanceolate, mostly acuminate, 

 coarsely and unequally serrate-dentate from below the middle, light green above, somewhat 

 paler and finely pubescent on the veins beneath ; terminal leaflet always and lateral usually 

 petiolulate: bud-scales villous: flowers small, green, on slender pedicels, drooping, the 

 (f fasckled, the 9 in somewhat elongated racemes : fruit cuneate at the base ; carpels at 

 m-aturity inch to inch and a half in length, with rather narrow body, a third to half the 

 length of the broad incurved wing. — Spec. ii. 1056; Wang. Nordam. Ilolzart. 30, t. 12, 

 f. 29; Michx. Fl. ii. 253; Guimp. Otto & Hayne, Abbild. Holzart. 118, t. 95; Sargent, 

 Silv. H. Ill, t. 96. A. {Negundo) fraxlnifolium, Nutt. Gen. i. 2.53. Nerjnndo areroldes, 

 Mcench, Meth. 334 ; Torr. & Gray, Fl. i. 250 ; Gray, Gen. 111. ii. 202, t. 175^ & Man. ed. 1-6. 

 N. trifoliatum, & lobafum, Raf. New Fl. Am. i. 48. * N. Negundo, Karsten, Deutsch. Fl. 596. 

 Ne.gundiumfraxinlfollum, Raf. Med. Rep. hex. 2, v. 352. Ridar Negundo, Hitchcock, Spring 

 Fl. Manhattan, 25. —A widely distributed tree, common especially westward, N. Vermont 

 to Connecticut, Central New York, and Ontario south to Florida and across the continent to 

 California.^ (Mex.) Passing into var. TexAnum, Pax (in Engl. Jahrb. vii. 212, in great 

 part; A. Califomirum, var. Texarmm, Pax, 1. c. xi. 75), a form with tomentulose branchlets 

 and somewhat more soft and copiously pubescent leaflets, occurring in Texas, Lind/ieimer, 

 and a very similar northern form (ranging through Ontario and Assiniboia, Afncoun, to 

 Montana, Srrilmer) with hoary-tomentulose branchlets. Both of these forms serve to con- 

 nect the type with 



Var. Calif ornicum, Wesmael. Bark "darker": l)ranchlets tomentulose: leaves 



