740 ACERACEAE 



long, acuminate at the apex, finely serrate, acute or acuminate at the base, finely pubescent 

 or glabrate in age : panicles 1-3 dm. long : flowers 2-3 cm. long : calyx oblong-campanu- 

 late, 1-1.5 cm. long, finely glandular : lobes broadly ovate, obtuse : corolla yellow or 

 purplish : petals glandular, those of the upper pair with oval blades which are about as 

 long as the villous claw, those of the lateral pair with oval or suborbicular blades narrowed 

 into winged villous claws which exceed them in length several times : stamens exserted : 

 filaments more or less villous : capsule unarmed, obovoid, 4-6 cm. in diameter : seeds de- 

 pressed, 2-3.5 cm. long. [A. flava Ait.] 



In woods and along streams, Pennsylvania to Iowa, Georgia and Texas. Spring. YELLOW BUCK- 

 EYE. SWEET BUCKEYE. LARGE BUCKEYE. 



5. Aesculus arguta Buckl. A shrub 1-3 m. tall, with a smooth bark. Leaf-blades 

 1-2 dm. in diameter : leaflets 7-9, the blades narrowly elliptic, 6-12 cm. long, acuminate 

 at both ends, finely serrate and incised above the middle, lustrous above, dull beneath, 

 villous beneath chiefly on the nerves: panicles 1-2 dm. long, finely villous: flowers 2.5 

 cm. long : calyx campanulate, 4-5 mm. long, minutely glandular ; lobes low and rounded : 

 corolla pale yellow : petals pubescent, villous at the base of the blade where they are 

 slightly dilated, those of the upper pair oval or broadly oblong, very thin, those of the 

 lateral pair with oblong blades which are narrowed into a thick portion about as long as 

 the claw : stamens exserted : anthers yellow : capsule subglobose, 3-4.5 cm. in diameter, 

 prickly : seeds 1.5-3 cm. broad. 



On plains or prairies. Missouri to Nebraska and Texas. Spring. SHRUBBY BUCKEYE. 



6. Aesculus glabra Willd. A tree sometimes 25 m. tall, with a maximum trunk 

 diameter of about 6 dm. Leaf-blades 1-3 dm. in diameter : leaflets 5 or rarely 7, the 

 blades elliptic or elliptic-oblanceolate, 7-18 cm. long, short-acuminate, finely serrate, be- 

 coming glabrous, cuneate at the base, nearly sessile or short-stalked : panicles 1-2 din. 

 long, finely pubescent : pedicels about 5 mm. long : flowers 12-18 mm. long : calyx 

 campanulate, 6-8 mm. long, finely pubescent ; lobes broadly ovate, rounded : corolla 

 greenish yellow : petals finely pubescent, crisped, dilated just above the claw, villous near 

 the base, those of the upper pair linear-spatulate, those of the lateral pair oval or oblong : 

 stamens 7, exserted : anthers orange : capsule obovoid or subglobose, 3-7 cm. in diameter, 

 prickly : seeds depressed, 2-4 cm. in diameter. 



In woods, Pennsylvania to Kansas, Alabama and the Indian Territory. Spring. OHIO BUCKEYE. 

 STINKING BUCKEYE. 



FAMILY 12. ACERACEAE J. St. Hil. MAPLE FAMILY. 



Shrubs or trees of temperate regions, of great economic value, often pos- 

 sessing a saccharine usually watery sap, the bark smooth or exfoliating. 

 Leaves opposite : blades simple or compound, commonly 3-lobed : stipules want- 

 ing. Inflorescence racemose or cymose, more or less compound, often congested. 

 Flowers perfect or polygamous, sometimes monoecious or dioecious, regular. 

 Calyx of 4 or 5, rarely 6-9, imbricated often colored deciduous sepals. Corolla 

 wanting, or often of as many petals as the sepals and alternate with them, inserted 

 on the margin of a hypogynous sometimes obsolete disk. Androecium of as 

 many stamens as there are sepals, often 8. Filaments filiform, distinct or some- 

 times almost wanting. Anthers introrse, versatile. Gynoecium of 2 more or 

 less united carpels. Ovary free. Styles united. Stigma 2-cleft. Ovules 2. 

 Fruit 2 nutlets with wings (samara). Seeds solitary, or rarely 2, with a mem- 

 branous testa. Endosperm wanting. Embryo with curved or coiled cotyledons. 



Leaves with simple or rarely digitately compound blades : flowers polygamo-dioecious. 1. ACER. 

 Leaves with pinnately compound blades : flowers dioecious. 2. RULAC. 



1. ACER L. 



Small or large trees, the trunk clothed with a close or exfoliating bark. Leaves 

 opposite : blades simple, lobed or digitately compound, or rarely entire. Flowers poly- 

 gamo-dioecious, regular, in axillary or terminal racemes or corymbs. Sepals 4 or 5, rarely 

 6-9. Disk wanting or cup-like, mostly lobed. Petals wanting or as many as the sepals, 

 imbricated. Stamens 4-9, often 8. Ovary 2-celled, 2-lobed, flattened contrary to the 

 septum. Samaras 2 together, with leathery or membranous reticulated wings. Seeds soli- 

 tary or rarely 2, flattened, ascending, the testa membranous. MAPLE. 



