148 ACER ACE AE (MAPLE FAMILY) 



ACERACEAE (Maple Family) 



Shrubs or trees; sap often sweet. Leaves opposite, simple or com- 

 pound, palmately lobed or rarely pinnate. Flowers polygamous 

 or dioecious, regular, cymose or racemose, axillary or terminal. 

 Calyx usually 5-parted. Petals none or 5. Disk present or none. 

 Stamens 3-12. Styles 2. Carpels 2, united at base, winged, 

 indehiscent. Seeds i in each carpel. — Many eastern species 

 cultivated for shade.* Only the following genus. 



ACER (Maple) 



(Celtic ac = hard or sharp ; hence L. acer = these plants ; since their 

 hard wood was prized for making weapons.) Maple sugar is derived from 

 A. saccharin urn of the east. 



A. Leaves simple or 3-foHoIate: disk present. 

 B. Leaves 7-9-lobed, 7.5-13 cm. wide; flowers in corymbs; fruit glabrous; mature 

 carpels spreading at about 180*, 2-3.2 cm. long. W. C. E. 



A. circinatum (vine maple) 



BB. Leaves 5-7-lobed, 15-37 cm. wide; flowers in racemes; fruit hispid; mature 



carpels spreading at about 90° or less, 3.7-5 cm. long. W. C. E. — Our finest 



native shade tree. A. macrophyllum (large-leaved maple) 



BBB. Leaves 3-5-lobed or 3-foIiolate, 2.5-7.5 cm. wide; flowers in corymbs; fruit 



glabrous; mature carpels spreading at about 90° or less, 2-3 cm. long. W. C. E. 



A. glabrum (rocky mountain maple) 

 AA. Leaves 3-9-foliolate; disk none. W. E. — Often planted for shade. 



A. negundo (box elder) 



BALSAMINACEAE (Touch-me-not Family) 



Herbs, annual, glabrous, succulent. Leaves alternate, thin, simple, 

 dentate, petioled. Flowers somewhat clustered, axillary, showy, 

 very irregular. Sepals apparently 4, the i notched at apex is prob- 

 ably 2 combined; rear one large, petal-like, saccate, often spurred. 

 Petals 2-5. Stamens 5, short; filament with scales on inner side, 

 somewhat united; anthers somewhat united. Ovary oblong, 

 when young 5-celled; cells several-ovuled. Fruit in ours a capsule, 

 oblong or linear, dehiscent into 5 valves. — Only the following 



genus. 



IMPATIENS (Touch-me-not) 



Petals 4, apparently only 2 by the union of the lateral with the lower. — 

 (Impatient in that the ripe capsule flies into pieces when touched.) 



* See Gray's New Manual, American Book Co. 



