ACER 



j. Wings about as long 

 as nutlets: hs. 

 truncate at base: . 6. truncatum 

 JJ. Wings about twice 

 as long as nutlets: 

 les. cordate or sub- 

 cordate 7. pictum 



HH. Bark remaining smooth 

 and lustrous for sev- 

 eral years, without or 

 with, few inconspicu- 

 ous lenticels, greenish 



or purplish 8. cappadoci- 



oo. Lvs. pubescent beneath, [cum 



usually 3-lobed, 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-oblong, rarely mixed 

 with a few 3-B-lobed hs.: 

 corymb nearly sessile, very 



large 10. catalpif olium 



EE. Winter-buds with 2 outer valvate 



scales: lobes serrate or doubly 



serrate: corymbs small. 



r. Lvs. 3-lobed or 3-foliolate, 



occasionally 5-lobed, pale 



or glaucescent beneath, 



quite glabrous 11. glabrum 



PF. Lm. 6-11-lobed, green be- 

 neath. 



G. Petioles and peduncles gla- 

 brous: ovary glabrous. 

 H. Sepals purplish; petals 

 white: hs. lobed nearly 



to the middle 12. circinatum 



HH. Sepals and petals pur- 

 plish: Ivs. lobed beyond 



the middle 13. palmatum 



oo. Petioles and peduncles 

 pubescent, at least while 

 young: ovary villous. 

 H. F Is. yellowish: Ivs. sub- 

 cordate or cordate, 

 sharply or doubly 



serrate 14. Sieboldia- 



HH. Fls. purple, larger: hs. |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 hs. sharply 



serrate. 

 H. Panicle only little 



longer than broad. 

 I. The Ivs. 6-lobed, 

 sharply and simply 



serrate 16. Oliverianum 



II. The hs. 3-lobed or 

 without lobes, dou- 

 bly serrate. 

 J. Foliage dull green; 

 Ivs. ovate-oblong, 



not lobed 17. tataricum 



JJ. Foliage shining 

 dark green: Ivs. 



S-lobed 18. ginnala 



HH. Panicle narrow, spike- 

 like, upright: Ivs. 3-5- 

 lobed, doubly serrate: 

 petals linear, much 

 longer than the sepals. 

 I. Foliage pubescent be- 

 neath: Ivs. S-, 

 rarely S-lobed .... 19. spicatum 

 II. Foliage glabrous or 

 pubescent be- 

 neath: hs. B-, 

 rarely 7-lobed .... 20. caudatum 

 oo. Edges of hs. coarsely or cre- 

 nately dentate, fi-l<>l '/. 



ACER 



197 



H. Panicles pendulous, 

 much longer than 

 broad. 



I. F r. hispid: hs. 10-lt 

 in. long, deeply 



lobed 21. raacrophyllum 



II. Fr. glabrous: Its. 4-6 



in. long 22. pseudoplat- 



HH. Panicles upright, little [anus 



longer than broad. 

 I. Blade with middle 

 lobe free nearly to 



the base 23. Heldreichii 



II. Blade with lobes di- 

 vided to the middle 

 or little beyond. 

 J. Lobes longer than 

 broad: hs. glau- 

 cescent beneath. . 24. Trautvetteri 

 jj. Lobes about as long 

 as broad: Ivs. 

 green beneath ... 25. insigne 

 FF. Lvs. quite entire, generally 



oblong 26. oblongum 



EE. Infl. racemose. 



F. Lvs. oblong, undivided, ser- 

 rate, with about 20 pairs of 

 parallel veins: winter-buds 

 with many imbricate scales.27. carpinif olium 

 FF. Lvs. lobed or undivided, with 

 about 10 pairs of veins or 

 less: winter-buds with % 

 outer valvate scales, 

 a. Sepals and petals 5; ra- 

 cemes terminal: hs. 

 brownish pubescent 

 beneath while young, at 

 least on the veins. 

 H. Outline of hs. 'oblong, 

 without lobes or with 

 # lobes near the base. 

 I. The hs. undivided, 



crenately serrate. . . 28. Davidii 

 n. The hs. lobed. 



j. With hs. green be- 

 neath, sharply 

 serrate, long-acu- 

 minate, slightly 



lobed 29. laziflorum 



JJ. With hs. glauces- 

 cent beneath, un- 

 equally serrate, 

 acuminate, often 



deeply lobed 30. cratsegif olium 



HH. Outline of hs. ovate or 



roundish, 5-lobed. . . .31. Tschonoskii 

 HHH. Outline of Ivs. obovate, 

 3-lobed, with the lobes 

 near or above the 

 middle. 



I. Young branchlets 

 bloomy: young Ivs. 

 densely brownish 

 villous on the veins 

 beneath: raceme 



pubescent 32. rufinerve 



n. Young branchlets not 

 bloomy: young un- 

 folding hs. brown- 

 ish mllous on the 

 whole under side, 

 primary veins gla- 

 brescent: raceme 

 often glabrous .... 33. pennsylvan- 

 oo. Sepals and petals 4 ;stam- [icum 



inate fls. from lateral 

 leafless buds: hs. doubly 

 serrate, 5-lobed or with- 

 out lobes. 



H. Lvs. undivided or in- 

 cisely lobed, ovate to 



oblong 34. tetramerum 



HH. Lvs. distinctly 5-lobed, 



roundish in outline. .35. argutum 

 cc. F Is. appearing long before the hs. 

 in dense lateral clusters: Ivs. 5- 

 lobed:fr. ripening in May or June. 



