ACERACEAE. 235 



Family 59. ACERACEAE. MAPLE FAMILY. 



Trees or shrubs; leaves simple or pinnately or palmately com- 

 pound, opposite, without stipules (in ours) ; flowers small, regular 

 (in ours) , polygamous or dioecious; sepals 4-5; petals often none 

 (in ours); stamens 3-12, inserted on the fleshy disk; ovary 2- 

 celled and lobed (in ours), with 2 ovules in each cell (in ours); 

 endosperm none. 



312. ACER. MAPLE. 



Trees or shrubs; leaves opposite, palmately-lobed, without 

 stipules; flowers small, polygamo-dioecious, in clusters; calyx 

 colored, usually 5-lobed; petals 5 and equal or none; stamens 

 3-12; styles 2; ovary 2-lobed, 2-celled; ovules 2 in each cell; 

 fruit a double samara, 2-winged above, separable at maturity, 

 each 1 -seeded. 



Flowers in racemes; fruit hispid. A. macro phyllum. 

 Flowers in corymbs; fruit glabrous. 



Leaves 3-5-lobed; fruit wings somewhat spreading. A. douglasii. 



Leaves 7-9-lobed ; fruit wings widely spreading. A . circinatum. 



Acer macrophyllum Pursh. Broadleaf Maple. Large tree reaching a 

 height of 10-30 m. and a diameter of 1-2 m.; bark longitudinally sulcate; 

 leaves 15-30 cm. long and broad, deeply 3-5-lobed, the lobes entire or more 

 commonly 3-5-cleft into acute sinuously-margined lobes, shiny above, paler 

 and somewhat pubescent beneath especially on the ribs; flowers greenish- 

 yellow, in pendent racemes 8-15 cm. long, the lower flowers infertile; calyx 

 campanulate; petals obovate, as long as the sepals; fruit very hispid, the 

 oblong slightly spreading wings 4-5 cm. long. 



Abundant in alluvial land; northward in Alaska to about latitude 55 and 

 southward in the mountains through California. First collected by Captain 

 Meriwether Lewis. 



Acer douglasii Hook. Dwarf Maple. Small tree, 3-10 m. high, with smooth 

 light-gray bark; leaves simple, rarely 3-foliolate, orbicular, acutish, 5-lobed, 

 coarsely serrate, truncate or subcordate at base, glabrous, dark-green above, 

 paler beneath, 5-10 cm. long; petiole slender; flowers polygamous, in small 

 corymbs; petals narrow, spatulate-oblong, veiny, about as long as the similar 

 sepals; fruit glabrous, roughened, the wings diverging at less than a right 

 angle, 2.5-3 cm. long. 



Along mountain streams, only rarely found at sea-level in our limits. Ex- 

 tends northward to Lynn Canal, Alaska. 



Acer circinatum Pursh. Vine Maple. Shrub or small tree, the trunk 

 3-10 m. high, rarely erect; bark smooth, gray; leaves 6-12 cm. long, nearly 

 orbicular, more or less cordate at base, cleft nearly to the middle into 7-9 

 acute serrate lobes, nearly glabrous when mature, somewhat villous when 

 young; flowers loosely corymbose; sepals oblong, acute, spreading; petals 

 hood-like, acutish, shorter than the sepals; fruit becoming glabrous, the wings 

 diverging nearly 180. 



Abundant in alluvial soil; found only west of the Cascade Mountains. 

 Northern limit near latitude 51; southern limit Mendocino and Trinity Coun- 

 ties, California. The leaves become purple-colored after midsummer and 

 gorgeously crimson in the fall. 



