SAPINDACEAE. 185 



Leaf-blades scarcely paler beneath than above ; lobes entire 



or undulate. 3. A. nigrum. 



Leaf-blades pale or glaucous beneath ; lobes coarsely toothed. 4. A. Saccharum. 



1. A. saccharinum L. Tree rarely 36 m. tall, the bark flaky at maturity, gray, 

 or that of the twigs reddisli-brown : leaf -blades about as long as broad, 10-15 

 cm. long, with 3-5 prominent incised lobes longer than the body, silky when 

 young, glabrate, bright-green above, glaucous or silvery-white beneath, truncate 

 or cordate at the base: calyx greenish or yellowish: samaras 5-6 cm. long, 

 tomentose, or glabrate at maturity, green, at length widely spreading. — 

 Common, on river-banks and on creek-banks. — Silver-maple. White- maple. 



2. A. rubrum L. Tree sometimes 35 m. tall, the bark dark-gray and fissured 

 on the trunk^ smooth and pale or white-gray on the branches: leaf -blades com- 

 monly broader than long, deep-green above, pale or glaucous beneath, mostly 

 shallowly 5-lobed, rather evenly serrate, cordate at the base: flower-clusters 

 red or yellowish: sepals nearly distinct: petals narrower than the sepals: 

 samara-wings commonly red. — Common, in low grounds and swamps. — Eed- 

 MAPLE. Swamp-maple. 



3. A. nigrum Michx. f. Tree sometimes 30 m. tall, the bark dark, coarsely 

 flaky, the twigs light orange-brown : leaf-blades mainly broader than long, 

 often 15-20 cm. broad, relatively thin, deep-green above, scarcely paler and 

 more or less downy beneath, with 3-5 entire or merely undulate lobes ; basal sinus 

 closed by the overlapping lobes: calyx canipauulate, about 5 mm. long; sepals 

 rounded : samaras 3-4 cm. long, slightly spreading. — S. Not common, on 

 river hills. — ■ Scliists. — Black-maple. 



4. A. Saccharum Marsh. Tree sometimes 40 m. tall, the bark usually separat- 

 ing in coarse scales at maturity, the twigs red-brown: leaf -blades firm, mostly 

 with 5 sinuate-toothed lobes, 8-15 cm. in diameter, deep-green above, pale or 

 glaucous beneath, with an open shallow sinus: calyx campanulate, about 5 mm. 

 long ; sepals obtuse : samaras slightly spreading, 3.5-4 cm. long. — Common, on 

 river-banks and creek-banks. — Sugar-maple. Hard-maple. Eock-maple. 

 Sugar-tree. 



2. NEGUNDO [Ray] Ludwig-Boehmer. Trees. Leaf-blades pinnately 

 compound. Flowers dioecious. Disk wanting. Stamens mostly 5 or 4. Fruit 

 resembling that of Acer. 



1. N. Negundo (L.) Karst. Tree becoming 25 m. tall: leaflets 3-9; blades 

 oval, ovate, or ovate-lanceolate, often 5-12 cm. long, coarsely toothed: flowers 

 greenish, drooping: samaras 2.5-3.5 cm. long. — Common, along creeks and 

 the Susquehanna. — Spr. — Box-elder. 



Family 7. SAPINDACEAE. Soapberry Family. 



Shrubs, trees, or vines. Leaves opi^osite or alternate : blades simple 

 or pinnate, sometimes 1-foliolate. Flowers dioecious, polygamous, or 

 polygamo-dioecious, or rarely perfect, in racemes, panicles, or coiymbs. 

 Calyx of 4 or 5 sepals. Corolla of 4 or 5 petals, or wanting. Disk some- 

 times gland-bearing. Androecium mostly of 5 or more stamens. Gynoe- 

 cium of 2-4 more or less united carpels. Fruit capsular or baccate. 



1. CARDIOSPERMUM L. Herbaceous or woody vines. Leaves alternate : 

 blades biternate or decompound. Flowers polygamo-dioeeious, irregular. 

 Sepals 4. Petals 4, unequal. Disk 1-sided, with 2 glands opposite the lower 

 petals. Stamens 8. Capsule bladdery. 



1. C. HalicacaTjum L. Leaflets 3 ; blades ovate to ovate-lanceolate, coarsely 

 serrate, incised, or parted: petals 3.5-4.5 mm. long: capsules obovoid. — M. 

 Occasional, about gardens. Nat. of trop. Am. — Sum. — Balloon-vine. 



