Dicotyls or Exogenoiis Plants. 35 



pubescent beneath ; cup-scales large and loosely imbricated or squar- 

 rose when dry, pubescent ; bark of trunk darker colored and rougher, 

 thicker and internally orange. 



Quer'-cus pa-lus'-tris Du Roi. Pin Oak: Swamp Spanish Oak. — Cup 



flat, saucer-shaped, fine-scaled, 5-7 lines broad, very much shorter than 

 the usually globose or depressed acorn which is 5-7 lines long; leaves 

 deeply pinnatifid with divergent lobes. In low grounds. 



c. Mature haves soft-doiuny beneath'.}: 



Quer'-cus il-i-ci-fo'-li-a Wang. Bear Oak ; Black Scrub Oak.— Dwarf 



and straggling, 3-8 ft. high; leaves 2-4 in. long, thickish, obovate, 

 cuneate at base, 3 to 7-lobed, white -downy beneath; acorn ovoid, 

 globular, 5-6 lines long. This species may occur in southern Ohio. 



b. Leaves entire or 'iuith a fe-M teeth or someivhat lobcd at the summit, 

 coriaceous^ 



Quer'-cus ni'-gra L. Black Jack; Barren Oak. — Leaves broadly wedge- 

 shaped, sometimes rounded at base, luidely dilated and usually some- 

 what .3-lobed at the summit, rusty pubescent beneath, 4-9 in. long; 

 cup top-shaped. 



Quer'-cus im-bri-ca'-ri-a Mx. Laurel Oak ; Shingle Oak. — Leaves en- 

 tire, lanceolate-oblong, shining above, down}' beneath. A h3'brid 

 between this species and O. coccinea, often called Quer'ciis lea'^ia 

 Nutt. (Lea's Oak), occurs sparingly in southern Ohio; its leaves are 

 usually somewhat irregularly and often bristly lobed. 



XV. Order UL-MA'-CE-ZE. ELM FAMILY.— Trees ; flowers polyga- 

 mous or dioecious-polygamous, not in catkins ; fruit a winged samara 

 or a drupe. 



Flowers preceding the leaves, fruit winged Ulmus. 1 



Flowers appearing with the leaves, fruit a drupe Cellis. 2 



1. Genus UL'-MUS. — Calyx 4-5-cleft, fruit a samara, winged all 

 around ; leaves strongly straight-veined, oblique at base. 



Ul'-mus pu-bes-'cens Walt. (U. fulvaM-K.) Red Elm ; Slippery Elm.— 

 Buds before expansion soft downy with rusty hairs ; leaves very rough 

 above, soft downy or slightly rough beneath ; branchles downy ; inner 

 bark mucilaginous. 



