ACERACEAE. 203 
A. Negundo. Blakeslee & Jarvis, 342, 546, pl.; Bosemann, 63; 
Brendel, 29, pl. 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, pl. 16. A. nikoense. 
Shirasawa, 278, pl. 12. A. obtusatum. Schneider, f. 220. A. 
palmatum. Schneider, f. 219; Shirasawa, 271, pl. 10. A. penn- 
sylvanicum. Blakeslee & Jarvis, 342, 532, pl.; Otis, 176; 
Schneider, f. 221; Trelease (2), 101, 102, pl. 14. A. pictum. 
Shirasawa, 280, pl. 12. A. platanoides. Blakeslee & Jarvis, 
342, 542, pl.; Bosemann, 63; Fant, 42, f. 40; Otis, 188; Schnei- 
der, 1 eee ety. Ward, '1* 154; 'f) °12:" Aweearini, “16, ‘pls Be As 
pseudoplatanus. Blakeslee & Jarvis, 342, 544, pl.; Bosemann, 
Ga* Want 42, £— 42: Otis; 190; Schneider; f£. 19, 217; Ward, 
1-156; 1. 732  Willkomm, 4,°9; 53, f:-’99; “Zuccarini, 16, pl... 8: 
A. purpurascens. Shirasawa, 280, pl. 12. A. pycnanthum. 
Shirasawa, 280, pl. 12. A. rubrum. Blakeslee & Jarvis, 324, 
f. 7, 342, 540, pl.; Otis, 186; Schneider, f. 221; Trelease (2), 
101, 104, pl. 15. <A. rufinerve. Shirasawa, 271, pl. 10. A. 
saccharinum. Blakeslee & Jarvis, 342, 538, pl.; Brendel, 29, 
pid: Hhiteheock (1), 3, £:'8,) €3), 11; Otis; 1845 -‘Tretease.(27, 
101, 103, pl. 15. A. saccharum. Blakeslee & Jarvis, 342, 536, 
pe: Brendel, 29, pl. 1; Hiteheock (1), 32 Otis, 180; Trelease 
(2), 102, 104, 105, pl. 16. A. Sieboldianum. Shirasawa, 276. 
A. spicatum. Blakeslee & Jarvis, 342, 534, pl.; Otis, 178; 
Trelease (2), 101, 102, pl. 14. A. tataricum. Boésemann, 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 
not opposite, and comparable leaves occur more confusingly 
in Viburnum and some other genera, certain species of which 
