DICOTYLEDONOUS PLANTS. 57 



of 3-12 stamens enclosed by a 4-8-parted perianth, often 

 containing an abortive ovary. Pistillate flowers solitary or 

 in small clusters, each consisting of a 3-celled ovary with 

 2 ovules in each c^ll, though rarely more than 1 ovule 

 matures ; styles short, erect, or recurved. Pistillate flowers 

 surrounded by a scaly involucre which at maturity becomes 

 a cup enclosing the base of the fruit or sometimes a large 

 part of it. Fruit an ovoid or subglobose, 1-seeded, thin- 

 shelled nut (acorn). 



A. Fruit biennial ; leaves entire or with bristle-pointed 

 lobes. "* 



1. Q. rubra, L. Red Oak. A large tree. Leaves oval or obovate, 

 green above, pale and slightly downy beneath, sinuses shallow and 

 rounded, lobes 8-12, taper-pointed ; petioles long. Cup saucer-shaped, 

 with fine scales ; acorn ovate or oblong, about 1 in. long. Common ; 

 wood not valuable ; leaves turning red after frost and often remain- 

 ing on the tree through the winter.* 



2. Q. coccinea, yar. tinctoria, Gray. Black Oak. A large tree 

 with rough, dark brown outer bark and thick, bright yellow inner 

 bark; leaves broadly oval, usually cut more than halfway to the 

 midrib, sinuses rounded ; lobes about 7, sharply toothed at the apex, 

 smooth above, usually downy on the veins beneath ; cup hemispher- 

 ical or top-shaped, with coarse scales, short-peduncled, enclosing about 

 half the roundish acorn. Common ; wood not valuable, but the 

 inner bark used for tanning and dyeing.* 



3. Q. falcata, Michx. Spanish Oak. A small or medium-sized 

 tree with leaves 3-5-lobed at the apex, obtuse or rounded at the 

 base, grayish-downy beneath, lobes lanceolate and often scythe- 

 shaped, sparingly cut-toothed. Cup top-shaped, with coarse scales, 

 enclosing about half the nearly round acorn. Conniion in dry 

 woods. Foliage quite variable in outline and lobing ; bark valu- 

 able for tanning.* 



4. Q. nigra, L. Black-jack Oak. A small tree ; leaves obovate, 

 usually with three rounded lobes at the apex, the lobes bristle-pointed, 

 rounded, or slightly cordate at the base, rusty-pubescent beneath, 

 shining above, coriaceous, short-petioled ; cup top-shaped, short- 

 peduncled, with coarse and truncate scales, enclosing about one- 

 third of the oblong-ovate acorn. An almost worthless tree, its 

 presence indicating a thin and sterile soil.* 



5. Q. Phellos, L. Willow Oak. A tree of medium size, leaves 

 lanceolate or elliptical, scurfy when young and becoming smooth 

 with age ; very short-petioled ; cup shallow, sessile ; acorn subglobose. 

 Wet soil ; often planted for shade.* 



