GERANIACE.E SAPINDACE^ 



315 



closely appressed to the tube, the tail of the spur curled under the spur: 

 pod opening elastically when ripe, throwing the seeds (the 5 valves quickly 

 curling from above downwards). Common in swales. 

 I. aurea, Muhl. ( J. pallida, Nutt.). Yellow jewel- 

 weed. Fig. 463. Leaves usually stronger-toothed, the 

 teeth usually ending in sharp points : flowers 1 in. long 

 and much broader than those of I. biflora, clear yellow, 

 the upper lip of two parts, the lower also of two parts 

 and nearly horizontal, the 2 sepals at apex of pedicel 

 large and not closely appressed, tail shorter : pods as 

 in the other. Less common than the other, but often 

 growing with it. 463. Impatiens aurea. 



XV. SAPINDACE^E. SOAPBERRY or MAPLE FAMILY. 



Trees or shrubs, of various habit: flowers polypetalous or apeta- 

 lous, often inconspicuous, 4- or 5-merous: stamens 10 or less, borne 

 on a fleshy ring or disk surrounding the single 2-3-loculed pistil: fruit 

 a pod or samara. A various family, largely tropical. Genera about 

 75, and species about 600 to 700. Maple, box-elder, buckeye, horse- 

 chestnut, bladder-nut, are familiar examples. 



1. ACER. MAPLE. BOX-ELDER. 



Trees or shrubs, with opposite lobed or parted leaves (pinnate in box- 

 elder) : flowers small and greenish or reddish, in early spring and often 

 from winter buds, in box-elder dioecious, in true maples 

 perfect (or imperfectly diclinous) : calyx about 5-cleft: 

 petals 5 or none: stamens usually 3-8: fruit a samara 

 with 2 seeds and 2 wings. Two shrubby woods maples 

 are common in some parts of the country. 



a. Maples: leaves simple, palmately lobed. 

 b. Flowers from lateral winter buds, preceding the 



leaves: fruit maturing very early. 

 A. saccharinum, Linn. (A. dasycarpnm, Waugh). 

 White or silver maple. Fig. 464. Fow- 

 ers greenish, with no petals : leaves 



very deeply 5-lobed, silvery white beneath, the narrow 

 divisions lobed and toothed : fruit with large spreading 

 wings, downy when young. Common along streams and in 

 low grounds; much planted. There is a cut-leaved form 

 known as Wier's maple, popular as a lawn tree. Wood 

 white. Linnseus thought it to be the sugar maple, hence 

 his name "saccharinum." 



A. rubrum, Linn. Red, soft, or swamp maple. Fig. 465. 

 Tree usually of only medium size: flowers red, with narrow-oblong petals: 



464. 

 Acer saccharinum. 



465. 

 Acer rubrum. 



