Click the number at the start of a key lead to highlight both that lead and its corresponding lead. Click again to show only the two highlighted leads. Click a third time to return to the full key with the selected leads still highlighted.
..2 Leaves broadest near or past the blade midpoint
..2 Leaves broadest below the blade midpoint
....3 Scales of the acorn cup prolonged and long tapered; lateral veins terminating in a well-developed bristle; [species planted, and naturalizing]; [section Cerris; "East Asia group"]
......4 Acorns on peduncles (2-) 4-7 cm long; acorns 1.5-2.5 cm long; veins ending in crenations usually 6-10 on each side of leaf; [section Quercus; subsection Prinoideae]
........5 Leaves mostly obovate (but sometimes narrower and broadest near the middle of the leaf blade or towards the base, especially on sun leaves), with rounded teeth (crenations), the teeth sometimes with a minute mucro; hairs of the leaf undersurface clustered in sessile, stellate-appearing clusters of 2-8 hairs; acorns 2.5-3.5 cm long; large trees; [section Quercus; subsection Albae].
..........6 Hairs of the leaf undersurface in clusters with a diameter of 0.15-0.5 mm, dense to sparse; bark of mature trees light gray, loose, breaking into plates or scales
..........6 Hairs of the leaf undersurface asymmetric, appressed-stellate, with a diameter of 0.1-0.25 mm, sparse; bark of mature trees dark gray, tight, deeply furrowed
........5 Leaves mostly narrowly elliptic, narrowly ovate, or narrowly obovate (but sometimes broadly obovate), with sharp ascending, often incurved teeth, the teeth ending in a hardened projection; hairs of the leaf undersurface tiny and stellate, with 6-10 rays parallel to the leaf surface; acorns 1-2 cm long; medium to large trees or stoloniferous shrubs; [section Quercus; subsection Prinoideae].
............ 7 Medium to large tree; veins ending in teeth usually 7-13 on each side of the leaf; leaves 8-20 cm long and 4-10 cm wide; [dry to moist calcareous woodlands and forests]
............ 7 Stoloniferous shrub to 5 m tall; veins ending in teeth usually 3-8 (-9)on each side of the leaf; leaves 4-10 (-14) cm long and 2-6 (-8) cm wide; [dry, often sandy and acid woodlands]