Acer platanoides L.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Species Description - Tree with widely spreading crown; lvs much like those of no. 2 [Acer saccharum Marshall], with 5–7 sharply acuminate lobes and few large teeth; juice milky (best seen at base of a detached petiole); fls yellow-green, in erect, pedunculate, rounded corymbs; pedicels glabrous; pet obovate, 5–6 mm, spreading; stamens seated on the disk; mericarps of the fr 3.5–5 cm, scarcely distended over the seed, the wings divergent at an angle of nearly 180°; 2n=26. Native of Europe, often found as an escape from cult. in vacant lots, and now spreading into successional forests. Apr., May.