ACERACEAE. 203 



A. Negundo. Blakeslee & Jarvis, 342, 546, pi.; Bosemann, 63; 

 Brendel, 29, pi. 1; Hitchcock (1), 3, (3), 11, (4), 135, f. 26- 

 31; Otis, 192; Schneider, f. 50, 219; Trelease (2), 105, illus- 

 tration on cover of separates. A. nigrum. Blakeslee & Jar- 

 vis, 536; Otis, 182; Trelease (2), 102, 105, pi. 16. A. nikoense. 

 Shirasawa, 278, pi. 12. A. obtusatum. Schneider, f. 220. A. 

 palmatum. Schneider, f. 219; Shirasawa, 271, pi. 10. A. penn- 

 sylvanicnm. Blakeslee & Jarvis, 342, 532, pi.; Otis, 176; 

 Schneider, f. 221; Trelease (2), 101, 102, pi. 14. A. pictum. 

 Shirasawa, 280, pi. 12. A. platanoides. Blakeslee & Jarvis, 

 342, 542, pi.; Bosemann, 63; Fant, 42, f. 40; Otis, 188; Schnei- 

 der, f. 51, 217; Ward, 1:154, f. 72; Zuccarini, 16, pi. 9. A. 

 pseudoplatamis. Blakeslee & Jarvis, 342, 544, pi.; Bosemann, 

 63; Fant, 42, f. 42; Otis, 190; Schneider, f. 19, 217; Ward, 

 1:156, f. 73; Willkomm, 4, 9, 53, f. 99; Zuccarini, 15, pi. 8. 

 A. purpurascens. Shirasawa, 280, pi. 12. A. pycnanthum. 

 Shirasawa, 280, pi. 12. A. rubrum. Blakeslee & Jarvis, 324, 

 f. 7, 342, 540, pi.; Otis, 186; Schneider, f. 221; Trelease (2), 

 101, 104, pi. 15. A. ruflnerve. Shirasawa, 271, pi. 10. A. 

 saccharinum. Blakeslee & Jarvis, 342, 538, pi.; Brendel, 29, 

 pi. 1; Hitchcock (1), 3, f. 8, (3), 11; Otis, 184; Trelease (2), 

 101, 103, pi. 15. A. saccharum. Blakeslee & Jarvis, 342, 536, 

 pi.; Brendel,. 29, pi. 1; Hitchcock (1), 3; Otis, 180; Trelease 

 (2), 102, 104, 105, pi. 16. A. Sieboldianum. Shirasawa, 276. 

 A. spicatum. Blakeslee & Jarvis, 342, 534, pi.; Otis, 178; 

 Trelease (2), 101, 102, pi. 14. A. tataricum. Bosemann, 62; 

 Schneider, f. 220. 



In their opposite lobed leaves, maples in general are fa- 

 miliar to most people who have even the slightest knowledge 

 of plants, and the characters of flowers and fruit on which 

 their botanical classification rests are distinctive. 



A novice is apt to mistake the sweet gum for a maple 

 through failing to observe that its leaves are alternate and 

 riot opposite, and comparable leaves occur more confusingly 

 in Viburnum and some other genera, certain species of which 



