IO ENGELMANN—OAKS OF THE UNITED STATES. [ 3 S 1 
wood, styles long and spreading or recurved, abortive ovules al¬ 
ways near the tip of the perfect seed. The leaves and their lobes 
are bristle-pointed, at least in youth ; lobes and teeth acute ; teeth 
sometimes spinous. Their stamens are usually less numerous, the 
scales of their cup membranaceous, the inner surface of their nut 
always tomentose ; the fruit generally matures in the second year : 
We may then arrange our oaks in the following order: 
Quercus, Lin. 
I- Lepidobalaniis, Endl. : Amenta mascula pendula; pollinis cellulae 
0.03-0.04 mm. latse; flores feminei a masculis distantes: stigmata dilatata. 
A. Leucobalanus : Ovula abortiva infera vel raro lateralia; stamina 
plerumque 6-8; stigmata sessilia vel subsessilia; nux intus glabra s. 
rarissime pubescens. 
ovula abortiva infera. 
«^. lyrata , 1 macrocarpa, 2 alba , lobata, stellata, Garryana, bico¬ 
lor, Mickauxii , 3 Prinus, 4 prinoides, Douglasii, undulata. 5 
11 Folia sempervirentia. 
dumosa, 6 Emoryi ,* 7 reticulata, 8 virens . 9 
lia; folia sempervirentia. . 
«^. cbrysolepis . 10 
b. Mel anobalanus : Ovula abortiva supera; stamina plerumque 
4-6; styli elongati demum recurvi; nux intus sericeo-tomentosa. 
«^. agrifolia, X1 kypoleuca , 12 pumila . 13 
t Folia decidua. 
Q.palustris, rubra, Sonomensh, coccinea, 14 ilicifolia, Georgia- 
na, Catesboei, falcata, nigra , cinerea, 15 aquatica, laurifolia, 16 
heterophylla, 17 imbricaria, Phellos. 
tf Folia sempervirentia. 
«^>. Wislizeni, 18 myrtifolia . 19 
II. Androgyne, A. DeC.: Amenta mascula erecta, basi flores femineos 
gerentia; pollinis cellulae fere 0.017 latse 5 stigmata linearia. 
densiflora. 
NOTES. 
1. Quercus lyrata, Walt., extends as far north as Taxodium does, to the 
banks of the lower Ohio in Illinois. 
2. Q.?nacrocarpa, Michx.,is extremely variable in the size of its acorns, 
and especially in , the depth and the margin of its cup, which sometimes 
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