The Flora of the Cayuga Lake Basin 293 



80. ACERACEAE (Maple Family) 



1. Acer (Tourn.) L. 



a. Leaves simple ; floral disk present. 



b. Flowers corymbose, umbellate, or capitate. 

 c. Flowers capitate, appearing before the leaves ; leaves whitened beneath, the 

 lobes 3-5, serrate; bark coarsely fissured. 

 d. Petals ; fruit woolly when young, with large divergent wings ; leaves 



deeply cleft or parted. 1. A. saccharinum 



d. Petals present ; fruit glabrous, with small and less divergent wings ; leaves 

 lobed. 2. A. rubrum 



c. Flowers loosely subumbellate, small, appearing with the leaves ; pedicels 

 drooping ; petals ; wings of fruit of medium size, little divergent ; leaves 

 very slightly whitened beneath, or green, the 3-5 lobes with a few coarse 

 distant teeth or subentire; bark coarsely or finely fissured (see also 3d c). 

 d. Leaves flat, not rugose, dull green, paler beneath and slightly glaucous, 

 glabrous ; stipules small, not covering the axillary bud of the next 

 season ; branchlets brown ; bark of trunk dark brown, breaking into 

 coarse ridges or plates. 3. A. sacchartim 



d. Leaves with drooping sides, rugose, usually pubescent and yellowish green 

 beneath, not glaucous ; stipules often large, when full-grown inclosing 

 the bud ; branchlets orange-brown ; bark, especially of the branches, light 

 orange-brown, breaking into fine uniform ridges. 4. A. nigrum 

 c. Flowers corymbose, large (10-15 mm. in diam.) ; pedicels not drooping; 

 petals large ; leaves green beneath, with 5-7 coarsely few-toothed lobes ; 

 bark finely fissured, close. 5. A. platanoides 



b. Flowers racemose. 

 c. Petals obovate, about 5 mm. long; racemes drooping; wings of fruit 7-10 

 mm. wide ; leaves finely serrate, scarcely villous beneath ; bark green, 

 striped with white. 6. A. pennsylvanicum 



c. Petals linear, about 2 mm. long ; racemes erect ; wings of fruit 3-5 mm. 

 wide ; leaves coarsely toothed, plainly villous beneath ; bark reddish brown, 

 not striped. 7. A. spicatum 



a. Leaves pinnate ; floral disk ; petals ; flowers racemose or subumbellate, 

 drooping; wings of fruit large, approximate, incurved. 8. A. Negundo 



1. A. saccharinum L. {A. dasycarpum of Cayuga Fl.) Silver Maple. 

 Swamps, river thickets, and other low woodlands ; frequent or locally common. 



March-Apr. 



Frequent in the valley of Cayuga Lake ; abundant from Ovid northw. on the 

 Ontario plain ; rare back from the lake in Lansing and Dryden ; apparently absent 

 in the towns s. and s. e. of Ithaca. 



N. B. to S. Dak., southw. to Fla., Ark., Okla., and Nebr. ; infrequent near the 

 coast. A tree primarily of the rich soils of the Mississippi Valley. 



2. A. rubrum L. Red Maple. Soft Maple. 



Swamps and damp hillsides, in sandy, gravelly, mucky, or even boggy, neutral 

 or acid soil, occasionally on the floating moors of peat bogs, rarely on calcareous 

 gravels or clays ; common. Apr. 



E. Que. and Me. to Man., southw. to Fla., Tex., and Kans., including the Coastal 

 Plain. 



3. A. saccharum Marsh. {A. saccharinum of Cayuga Fl.) Sugar or Rock Maple. 



Upland woods, in gravelly, mostly calcareous, soils ; common. May 12-30. 



Rare in the lighter chestnut acid soils of the hills w., s., and s. e. of Ithaca; in- 

 frequent along the cliffs of Cayuga Lake, but common and a characteristic forest 

 tree in the McLean region; locally abundant wherever the soil is suitable. 



Newf. to Man., southw. to Fla. and Tex. ; rare or absent on the Coastal Plain. 



