202 



ACERACEAE. 



Acer. Maple. 

 (Family Aceraceae). 



Shrubs or round-topped trees: 

 deciduous. Wood rather hard, 

 brownish, diffused-porous. Twigs 

 moderate, nearly terete or some- 

 what 6-sided: pith round, con- 

 tinuous, pale. Buds moderate, 

 solitary or sometimes collaterally 

 multiple, ovoid or conical, dis- 

 tinctly stalked in some groups, 

 with 2 or several pairs of scales. 

 Leaf-scars U-shaped: bundle- 

 traces 3 or occasionally 5 or 7 or 

 9, or multiplied: stipule-scars 

 lacking. The box elders are segre- 

 gated frequently as Negundo or 

 Rulac. 



Winter-character references: 

 Acer argutum. Shirasawa, 275, pi. 

 21. A. calif ornicum. Schneider, 

 f. 219. A. campestre. Bosemann, 

 63; Fant, 42, f. 41; Schneider, 

 f. 217; Ward, 1:170, f. 84; Zuccarini, 14, pi. 8. A. carpinifolium. 

 Shirasawa, 278. pi. 12. A. circinatum. Schneider, f. 218; 

 Trelease (2), 101. 103. pi. 14. A. c'is si folium. Shirasawa, 272, 

 pi. 10. A. crataegifolium. Shirasawa, 271, pi. 10. A. disty- 

 lum. Shirasawa, 275, pi. 11. A. Drummondii. Trelease (2), 

 101, 104, pi. 15. A. floridanum. Trelease (2), 102, 105, pi. 

 16. A. Ginnala. Schneider, f. 220; Shirasawa, 279, pi. 12. 

 A. glabrum. Trelease (2), 101, 102, pi. 14. A. grandidenta- 

 tum. Trelease (2), 102, 104, pi. 16. A. japonicum. Shira- 

 sawa, 276, pi. 11. A. leucoderme.. Trelease (2), 105. A. 

 macrophyllum. Schneider, f. 218; Trelease (2), 101, 103, pi. 

 15. A. monspessulanum. Bosemann, 63; Schneider, f. 221. 



