ACERACEAE. 



Family 9. ACERACEAE St. Hil. 



Maple Family. 



Trees or shrubs, with watery often saccharine sap, opposite simple and 

 palmately lobed (rarely entire) or pinnate leaves, and axillary or terminal 

 cymose or racemose regular polygamous or dioecious flowers. Calyx gener- 

 ally 5- parted, the segments imbricated. Petals of the same number, or 

 none. Disk thick, annular, lobed, sometimes obsolete. Stamens 4-12, 

 often 8 ; filaments filiform. Ovary 2-lobed, 2 celled ; styles 2, inserted 

 between the lobes. Fruit of 2 long-winged samaras, joined at the base 

 and i-seeded (rarely 2-seeded). Seeds compressed, ascending ; cotyledons 

 thin, folded. The family consists of the following genus and Dtpteronia 

 Oliver, of central Asia. There are about 100 species of Maples. 



i ACER L. (See Appendix.) 



[Ancient name of the maples.] Besides the following, some 5 others occur in 

 southern and western North America. 



Leaves simple, palmately lobed. 



Flowers in dense sessile lateral clusters, unfolding before the leaves. 



Petals none; ovary tomentose ; samaras divergent. i. A. saccharinum. 



Petals present ; ovary glabrous : samaras incurved. 



Leaves pale and glabrous or but slightly pubescent beneath. 



2. A. rubrum. 

 Leaves densely whitish-pubescent beneath ; southern. 



3. A. Drummondii. 

 Flowers corymbose, unfolding with the leaves. 



Flowers long-pedicelled, drooping; large trees. 



Leaves pale and nearly glabrous beneath. 4. A. Saccharum. 



Leaves green and pubescent, at least on the veins, beneath. 



5. A. nigrum. 



Flowers short-pedicelled, erect ; shrub or small tree. 6. A. glabrum. 

 Flowers racemed, terminal, unfolding after the leaves. 



Racemes drooping; leaves finely serrate. 7. A. Pennsylvanicum. 



Racemes erect ; leaves coarsely serrate, 8. A. spicatum. 



Leaves pinnate. t 9. A. Negundo. 



1. Acer saccharinum L. SILVER MAPLE. SOFT OR WHITE MAPLE. (I. F. f. 

 2372.) A tree with flaky bark. Leaves I- 1.5 dm. long, deeply 5-lobed, the lobes 

 rather narrow, acuminate, coarsely and irregularly dentate, truncate or slightly cor- 

 date at the base, green above, silvery white and more or less pubescent beneath; 

 flowers greenish or red; fruiting pedicels elongating; samaras at length 5-7 cm. 

 long, the wing often 1.2 cm. wide. Along streams, N. B. to Fla., S. Ont., Dak., 

 Neb. and the Ind. Terr. Yields maple sugar in small quantities. Feb. -April. 



2. Acer rubrum L. RED, SCARLET OR WATER MAPLE. SWAMP MAPLE. 

 (I. F. f. 2373.) A tree with flaky or smoothish bark. Twigs reddish; leaves 

 7-10 cm. long, cordate at the base, sharply 3~5-lobed, the lobes irregularly den- 

 tate, acute or acuminate, green above, generally whitish beneath; flowers reddish 

 or yellowish; petals narrowly oblong; stamens 3-6; fruiting pedicels elongating; 

 samaras 1.8-2.5 cm - l n g> the wing 6-8 mm. wide. In swamps and low grounds, 

 N. B. to Manitoba, Fla. and Tex. Foliage crimson in autumn. March-April. 



3. Acer Drummondii H. & A. DRUMMOND'S MAPLE. (I. F. f. 2374.) 

 Similar to the preceding. Leaves 7-15 cm. long, thicker, 3-lobed, or sometimes 

 5-lobed, obtuse or cordate at the base, the lobes shorter, broader, acute or acumi- 

 nate; young twigs and petioles more or less tomentose; fruiting pedicels 2. 5-5 cm. 

 long; samaras 3.75-6.25 cm. long, the wing 1-2 cm. broad at middle. In swamps, 

 southern Mo. to Ga., Fla. and Tex. Fruit scarlet, ripening in March or April. 



4. Acer Saccharum Marsh. SUGAR OR ROCK MAPLE. SUGAR-TREE. (I. F. 

 f- 2 375-) A large tree. Leaves 7.5-15 cm. long, dark green above, cordate or 

 truncate at the base, 3-7-lobed, the lobes acuminate, irregularly sinuate, the sin- 

 uses rounded; flowers in sessile corymbs, greenish yellow; petals none; samaras 

 glabrous, slightly diverging, 2.5-3.75 cm. long, the wing 6-10 mm. wide. In rich 



