ACER 



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197 



J. Wings about (u long 

 as nutlets: Ivs. 

 truncate at base: . 6. tTuncatum 

 jj. Wings about twice 

 as long as nutlets: 

 li^s. cordate or sub- 

 cordate 7. pictum 



HH. Bark remaining smooth 

 and lustrous for sev- 

 eral years, without or 

 viilh few inconspicu- 

 ous lenticels, greenish 



or purplish 8. cappadoci- 



GQ. Lvs. pubescent beneath, [cum 



usually S-lobcd, occa- 

 sionally 5-lobed or quite 

 entire: corymbs nearly 



sessile, very large 9. longipes 



FFF. Lobes none or not prevalent, 

 the Ivs. quite entire, ovate to 

 ovate-oblotig, rarely mixed 

 with a few 3— 5-lobed Ivs.: 

 corymb nearly sessile, very 



large 10. catalpif olium 



EB. Winter-buds with 2 outer valvate 



scales: lobes serrate or doubly 



serrate: corymbs small. 



F. Lvs. S-lobed or S-foliolate, 



occasionally 5-lobed, pale 



or glaucescent beneath, 



quite glabrous 11. glabrum 



FF. Lvs. 5-11-lobed, green be- 

 neath. 

 G. Petioles and peduncles gla- 

 brous: ovary glabrous. 

 H. Sepals purplish; petals 

 white: lvs. lobed nearly 



to the middle 12. circinatuzn 



HH. Sepals and petals pur- 

 plish: lvs. lobed beyond 



the middle 13. palmatum 



QG. Petioles and peduncles 

 pubescent, at least while 

 young: ovary villous. 

 H. Fls. yellowish: lvs. sub- 

 cordate or cordate, 

 sharply or doubly 



serrate 14. Sieboldia- 



HH. Fls. purple, larger: lvs. [num 



deeply cordate, in- 



cisely serrate 15. japonicum 



DD. Arrangement of infl. paniculate 

 or racemose. 

 E. Infl. paniculate (nearly corym- 

 bose in No. 16). 

 F. Lvs. dentate or serrate, usu- 

 ally lobed. 

 a. Edges of lvs. sharply 

 serrate. 

 H. Panicle only little 

 longer than broad. 

 I. The lvs . S-lobed, 

 sharply and simply 



serrate 16. Oliverianum 



n. The lvs. 3-lobed or 

 without lobes, dou- 

 bly serrate. 

 3. Foliage dull green; 

 lvs. ovate-oblong, 



not lobed 17. tataricum 



JJ. Foliage shining 

 dark green: lvs. 



3-lohed 18. ginnala 



HH. Panicle narrow, spike- 

 like, upright: lvs. 3-5- 

 lobed, doubly serrate: 

 petals linear, much 

 longer than the sepals. 

 I. Foliaye pubescent be- 

 neath: lvs. S-, 



rarely 5-lobed 19. spicatum 



ir. Foliage glabrous or 

 pubescent be- 

 neath: lvs. 5-, 

 rarely 7-lobed ... 20. caudatum 

 GO. Edges of lvs. coarsely or cre- 

 nately dentate, 6~lobed. 



I. 



II. 



FF. 



FF. 



H. Panicles pendulous, 



much longer than 



broad. 



I. Fr. hispid: lvs. 10-12 



in. long, deeply 



lobed 21. 



II. Fr. glabrous: lvs. U-6 



in. long 22. 



HH. Panicles upright, little 

 longer than broad. 

 Blade with middle 

 lobe free nearly to 



the base 23. 



Blade with lobes di- 

 vided to the middle 

 or little beyond. 

 J. Lobes longer than 

 broad: lvs. glau- 

 cescent beneath. . 24. 

 JJ. Lobes about as long 

 as broad: lvs. 

 green beneath. . .25. 

 Lvs. quite entire, generally 



oblong 26. 



EE. Infl. racemose. 



F. Lvs. oblong, undivided, ser- 

 rate, with about 20 pairs of 

 parallel veins: winter-buds 

 with many imbricate scales.27, 

 Lvs. lobed or undivided, with 

 about 10 pairs of veins or 

 less: winter-buds with 2 

 outer valvate scales. 

 . Sepals and petals 5; ra- 

 cemes terminal: lvs. 

 brownish pubescent 

 beneath while young, at 

 least on the veins. 

 H. Outline of lvs. oblong, 

 without lobes or with 

 2 lobes near the base. 

 I. The lvs. undivided, 

 crenately serrate. . . 28. 

 The lvs. lobed. 

 J. With lvs. green be- 

 neath, sharply 

 serrate, long-acu- 

 minate, slightly 



lobed 29. 



With lvs. glauces- 

 cent beneath, un- 

 equally serrate, 

 acuminate, often 



deeply lobed .30. 



HH. Outline of lvs. ovale or 



roundish, 5-lobed. . . .31. 



HHH. Outline of lvs. obovate, 



S-lobed, with the lobes 



near or above the 



middle. 



I. Young branchlets 



bloomy: young lvs. 



densely brownish 



villous on the veins 



beneath: raceme 



pubescent 32. 



n. Young branchlets not 

 bloomy: young un- 

 folding lvs. brown- 

 ish villous on the 

 whole under side, 

 primary veins gla- 

 brescent: raceme 

 often glabrous . . . .33. 

 GG. Sepals and petals 4: stam- 

 inaie fls. from lateral 

 leafless buds: lvs. doubly 

 serrate, 5-lobed or with- 

 out lobes. 

 H. Lvs. undivided or in- 

 cisely lobed, ovate to 



ol)long 34. 



HH. Lvs. distinctly 5-lobed, 



roundish ^^outline . .35. 

 cc. Fls. appearing long b^^e the lvs. 

 in dense lateral clusters: lvs. 5- 

 lobed:fr. ripening in May or June. 



macrophyllum 



pseudoplat- 



[anus 



Heldreichii 



Trautvetteri 



insigne 

 oblongum 



carpinif olium 



n. 



JJ. 



Davidii 



laxiflorum 



cratsegifolium 

 Tschonoskii 



rufinerve 



pennsylvan- 

 [icum 



tetramerum 

 argutum 



