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3 Leaves small, thinner, glabrate or grayish-pubescent beneath, with conspicuous tufts of yellowish tomentum in the axils of the principal veins beneath; buds small, 3-5 mm long, ovate-lanceolate, grayish-pubescent; cups 10-15 mm wide, rounded or flattened at the base, with small grayish brown or red-brown scales closely appressed in a thin edge, covering less than one-third of the acorns; acorns 15-18 mm long, glabrous, or nearly so, sometimes faintly striated | |
3 Leaves usually large, thick, leathery, usually rusty-tomentose on the under surface, less conspicuously tufted with tomentum in the axils of the three primary veins beneath; buds large, 6-8 mm long, ovoid, or oval, prominently angled, covered with rusty-brown hairs; cups 10-20 mm wide, mostly turbinate or hemispheric, decidedly tapering at the base, the scales at the thick edge squarrose or loosely imbricate, cinnamon-red; acorns oblong, usually broader below than above, about 18 mm long, light yellow-brown, often striate, the shell usually lined with dense fulvous tomentum, enclosed for one-third to nearly two-thirds their length in the cups | |
2 Leaves 2-10 (-15) cm long, mostly with cuneate or rounded bases (in some species sometimes subcordate, truncate, or oblique); lower leaf surfaces glabrous, glabrescent, or pubescent, but the pubescence not orange and glandlike. | |
4 Leaves shallowly and regularly serrate; leaves densely white pubescent beneath; [exotic species, rarely planted and persistent; [section Cerris; "West Asia group"] | |
7 Shrubs or small trees to 3(-5) m tall, often forming thickets, trunks multiple from near ground; acorn 7-12 (-15) mm long, 7-10 mm in diameter; [of dry limestone hills of OK and TX] | |
7 Trees to 20 m tall, trunk usually solitary; acorn 12-15 (-18) mm long, 8-12 (-17) mm in diameter; [of moist bottomlands, riparian habitats and calcareous bluffs of SC west to TX] | |
6 Leaves bright green or orange-scurfy beneath; [section Lobatae; subsection Phellos]. | |
9 Leaves evergreen, (including the petiole) usually < 4 cm long (sometimes to 9 cm long) and < 2 cm wide (to 6 cm wide); lower leaf surface usually entirely glabrous at maturity (rarely with pubescence in the vein axils); leaf blades rarely lobed; [shrub to scrubby tree of sandhills in se. SC and southward] | |
12 Twigs of the year densely and finely hairy, obscuring the surface; leaves (at maturity) sparsely pubescent beneath; [scrubby trees of sandhills from se. SC south to FL, west to s. AL]; [section Quercus; subsection Stellatae] | |
13 Leaves predominantly lanceolate, mostly 6-12 cm long and 0.7-2 cm wide, most of them 5-8× as long as wide, the apex acute; mature leaves with tufts of hairs in the vein axils below, and sometimes also some pubescence on the blade surface near the midrib; blades never with lobes or teeth; leaves deciduous in autumn; young leaves bronze red, emerging tightly rolled lengthwise and appearing linear; [trees of bottomlands and upland depression swamps, mesic uplands, and also weedy and frequent in disturbed successional habitats] | |
13 Leaves predominantly oblanceolate, obovate, or rhombic, mostly 2.5-10 cm long and 1.5-4 cm wide, most of them 2-5× as long as wide, the apex acute, obtuse, or rounded; mature leaves with or without tufts of hairs in the vein axils below, lacking pubescence on the blade surface; blades sometimes with 1-5 lateral lobes or teeth; leaves persisting until spring, or tardily and irregularly deciduous in winter; young leaves red, yellow, or green, not emerging tightly rolled lengthwise; [trees primarily either of swamp forests, maritime forests, or sandhills, not typically weedy]. | |
14 Mature leaves entirely glabrous below; leaves mostly with acute apices and bristle tips (rarely a few rounded), mostly 2.5-8 cm long and 1-2 (-3) cm wide, the upper surface shiny, the vein network not readily visible when backlit; leaves evergreen (persisting until spring); petiole 0.5-2 mm long; leaves of vigorous growth often with dentate lobes; [trees of dry sandy habitats, such as sandhills, maritime forests, and dry hammocks] | |
14 Mature leaves with tufts of stellate trichomes in the vein axils; leaves mostly with rounded apices (rarely a few acute and then bristle-tipped), mostly 5-10 cm long and (1.8-) 2-4 cm wide, the upper surface dull, the vein network readily visible when backlit; leaves tardily deciduous (at least northwards in the Southeast); petiole 2-6 mm long; leaves of vigorous growth rarely lobed, and then not dentate; [trees of moist habitats, such as floodplain forests, mesic slopes, and moist hammocks] | |
11 Leaves (at maturity) persistently and densely pubescent on the surface below, the pubescence in some species so dense and tight as to be difficult to perceive without at least 10× magnification. | |
15 Leaves bristle-tipped (sometimes the bristle fallen or broken off, but leaving a truncate scar), deciduous in autumn; multi-armed trichomes of the rosulate or multiradiate types, many of the arms ascending or erect (never with the stellate or fused-stellate trichomes characteristic of the live oaks); acorns maturing in 2 years (immature acorns present through the winter on fruiting trees); [section Lobatae; subsection Phellos]. | |
16 Leaves (including petiole) mostly 4-11 cm long, 0.5-3.0 cm wide; lower leaf surface densely covered with soft hairs; leaves lustrous dark-green or bluish-green above; [stoloniferous shrubs and small to medium trees of the Coastal Plain]. | |
17 Leaves 0.5-1.5 cm wide, mostly 4-8× as long as wide, lustrous dark-green above; acorns 8-12 mm long; petioles 1-3 mm long; [plant a stoloniferous shrub, to 1 m tall (or to 2 m in fire-suppressed pinelands)] | |
15 Leaves not bristle-tipped, evergreen (overwintering, falling with the expansion of new leaves in the spring) or deciduous (in Q. oglethorpensis and Q. mohriana); multi-armed trichomes of the fused-stellate and stellate types, the arms parallel to the leaf surface, radiating from a well developed disc that appears as a white eye or dot at 20-40× magnification (or rosulate or multiradiate in Q. oglethorpensis and Q. mohriana); acorns maturing in 1 year (immature acorns not present through the winter, unless aborted). | |
19 Stellate hairs of the leaf undersurfaces with 1-4 rays; bark light gray, resembling that of Quercus alba; [bottomlands and upland clay flats, GA and SC]; [section Quercus; subsection Stellatae] | |
18 Stellate hairs of the leaf undersurfaces appressed to the surface; leaves evergreen (overwintering, falling with the expansion of new leaves in the spring); bark (on the tree species) brownish, deeply furrowed; [trees and stoloniferous shrubs either of sandy habitats of the Coastal Plain of VA s. to FL or of rocky limestone areas of c. OK and c. TX]; [section Virentes]. | |
20 Plant a stoloniferous shrub, to 1 m tall (or to 2 m in fire-suppressed pinelands) and producing acorns at that size | |
21 Leaf blades with the margins strongly revolute, and also the sides of the blades generally rolled downward and obscuring part of the lower surface, the leaf appearing boatlike (the depth of the "boat" often approaching the width of the leaf); midvein and major lateral veins impressed on the upper surface and raised on the lower surface (the lower surface therefore appearing rugose); buds dark brown; cup scales gray-tipped; pubescence of the lower surface stellate, both appressed and erect, the individual stellae readily visible at 20× magnification (sometimes at 10× magnification); acorns (1-) 2 (-6) per stalk; [typically a small tree of dry sands] | |
21 Leaf blades flat, or the margins slightly to strongly revolute, the sides of the blade sometimes rolled downward, usually not obscuring part of the lower surface, the leaf not boatlike (the leaf much wider than deep); midvein and major lateral veins not impressed (or very slightly so) on the upper surface and only very slightly, if at all, raised on the lower surface (the lower surface therefore not appearing notably rugose); buds red-brown; cup scales red-tipped; pubescence of the lower surface stellate, all of it tightly appressed, the individual stellae readily visible only at 30× magnification (sometimes barely distinguishable at 20× magnification); acorns 1-2 per stalk. | |