742 ACERACEAE 



staminate flowers surrounded by the base of the filaments : fruit drooping : samaras slightly 

 spreading, 3.5-4 cm. long. [^1. saccharinum Wang., not L. ] 



In rich woods or open grounds, Newfoundland to Manitoba, south to Georgia and Texas. Spring. 

 Sugar Maple. Hard Maple. Sugar-tree. Rock Maple. Black Maple. 



6. Acer Florid^num (Chapm. ) Pax. A graceful tree rarely over 18 m. tall, 

 with a maximum trunk diameter of about 1 m., the bark rather close, but rough in age, 

 chalky white. Leaves appearing with the flowers ; blades rather broader than long, 5-6 

 cm. broad, with 3-5 blunt few-toothed lobes about as long as the body, deep green above, 

 glaucous and more or less pubescent beneath, truncate or shallowly cordate at the base : 

 pedicels sparingly pubescent at least until the fruit matures : calyx campanulate, 1-1.5 mm. 

 long : sepals broad, somewhat pubescent : fruit green : samaras 1.5-2 cm. long, sparingly 

 pubescent near the base, the wings rather widely spreading. 



In river swamps, Georgia to Florida and Louisiana. Spring. 



7. Acer leucod^rme Small. A shrub or small tree reaching a height of 8 m., 

 with a trunk diameter of 1-5 dm., clothed with a smooth white bark, except the gray or 

 reddish branchlets. Leaves appearing with the flowers ; blades broader than long, or 

 rarely orbicular in outline, mostly 4-lobed, sometimes imperfectly 5-Iobed, 4-9 cm. in 

 diameter, cordate or truncate, with a rather open and shallow sinus, dark green, glabrous 

 and marked with light nerves above, greenish, tinged with red, prominently nerved and 

 velvety (especially to the touch) beneath, the lobes acute or acuminate (the 4th. or 5th., 

 when present, obtuse), each, or the terminal one only with two obtuse teeth: fruit 

 drooping : wings of the samaras oblong-spatulate, 1-2 cm. long, red, conspicuous, parallel 

 or nearly so (more or less spreading when the fruits separate at maturity). 



On rocky river banks, North Carolina to Georgia and Louisiana. Spring. 



8. Acer splcatum Lam. A shrub or small tree, sometimes 10 m. tall, with a max- 

 imum trunk diameter of 20 dm., the bark thin, relatively smooth, the twigs tomentulose 

 or glabrate in age. Leaves appearing before the flowers : blades mostly longer than broad, 

 mainly 3-lobed, sometimes with 2 additional lobes near the base, serrate, glabrate above, 

 paler and more or less tomenulose beneath, cordate or subcordate : panicles terminal, 

 raceme-like, 8-15 cm. long, peduncled, erect or ascending, many-flowered : pedicels spread- 

 ing, 6-10 mm. long, or longer at maturity: petals linear or spatulate, twice or thrice as long 

 as the sepals : stamens mostly 8, equal : staminate flowers with a pubescent rudimentary 

 pistil : disk with almost distinct glands : fruit green, about 2.5-3.5 cm. broad, the wings 

 of the samaras spreading at about 90 degrees. 



In damp rocky woods and on mountain slopes, Newfoundland to Manitoba, Minnesota and along 

 the mountains to Georgia. Spring and early summer. Mountain Maple. Low Maple. 



9. Acer Pennsylvdnlcum L. A shrub or tree, rarely over 11 m. tall, with a maximum 

 trunk diameter of about 5 dm., the bark relatively smooth, longitudinally striped. Leaves 

 appearing before the flowers ; blades sometimes broader than long, 1-3 dm. broad, deep 

 green, with 3 nearly erect acuminate lobes, sometimes with 2 additional lobes, finely and 

 doubly serrate, glabrous above, finely pubescent beneath, rounded or subcordate at the base : 

 racemes drooping, 8-15 cm. long, relatively few-flowered : pedicels not spreading, 5-10 

 mm. long : petals pale or yellowish green, obovate, slightly surpassing the oblong sepals : 

 stamens included : filaments outside the well-developed crenate disk : staminate flowers 

 with rudimentary pistils : fruit bright green, 3.5-5.5 cm. broad, glabrous, the wings of the 

 samaras spreading at an angle of about 120 degrees. 



In rockv woods, Nova Scotia to Lake Superior, southward, especially along the mountains, to 

 Georgia. Spring. Striped Maple. Mountain Alder. Striped Dogwood. 



2. RULAC Adans. 

 Widely branching trees, the trunk with scaly bark, the branches light green. Leaves 

 opposite: blades pinnately compound, the leaflets usually toothed. Flowers dioecious, 

 appearing before the leaves : the staminate in drooping clusters, the pistillate in drooping 

 racemes. Sepals 4 or 5, relatively small. Petals wanting. Stamens 4-5. Disk obsolete. 

 Ovary, and fruit, nearly similar to that of Acer. Boxelder. 



Twigs and petioles essentially glabrous : leaflets thin, coarsely toothed. 1. i?. Kegundo. 



Twigs and petioles copiously pubescent : leaflets thick, lobed. 2. R. Texana. 



1. Rulac Negundo (L. ) A.S.Hitchcock. A tree, with conspicuously light green 

 foliage, rarely 25 ni. tall, witli a maximum trunk diameter of fully 1 m., the bark flaky 

 at maturity: leaves numerous ; petioles essentially glabrous ; blades pinnately 3-9-f olio- 

 late ; leaflets oval, ovate or ovate-lanceolate, often 5-12 cm. long, accuminate, coarsely 

 toothed, more or less pubescent on or near the nerves beneath : flowers dioecious, appear- 



