394 ABOUT THE OAKS OF THE UNITED STATES. 
sometimes spinous-tipped ; their stamens are more numerous, the scales of the cup more or less 
knobby at base, the inner surface of the nut glabrous or (rarely) pubescent; the fruit generally 
matures in the first year. 
The black-oaks have dark, furrowed bark, brittle and porous wood, styles long and [381 (10)] 
spreading or recurved, abortive ovules always near the tip of the perfect seed. The 
leaves and their lobes are bristle-pointed, at least in youth; lobes and teeth acute; teeth some- 
times 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, Liny. 
L SORRGI MOM RS Endl. : Amenta mascula pendula; pollinis cellule 0.03-0.04 mm. late ; flores feminei a masculis dis. 
dilata 
As aN : Ovula abortiva infera vel raro lateralia; stamina plerumque 6-8; stigmata sessilia vel subsessilia; nux 
intus glabra s. rarissime pubescens. 
* Maturatio annua ; nux intus glabra ; ovula abortiva infera. 
+ Folia decidua, 
Q. lyrata,) macrocarpa,? alba, lobata, stellata, Garryana, bicolor, Michauxii,8 Prinus,4 prinoides, Douglasii, undulata5 - 
tt Folia sempervirentia. 
Q. dumosa,§ Emory,’ reticulata,’ virens.® 
** Maturatio biennis ; nux intus pubescens ; ovula abortiva infera vel lateralia ; folia sempervirentia. 
Q. chrysolepis.10 
B, MELANOBALANUS: Ovula abortiva supera ; stamina plerumque 4-6; styli elongati demum recurvi ; nux intus sericeo- 
* Maturatio annua ; folia persistentia s. subpersistentia. 
Q. agrifolia,4 hypoleuca,}2 pumila.1s 
* * Maturatio biennis. 
t Folia decidua. 
Q. palustris, rubra, Sonomensis, coccinea,'4 ilicifolia, Georgiana, Catesberi, falcata, nigra, cinerea,5 aquatica, laurifolia,\é 
heterophylla,\! imbricaria, Phellos. 
++ Folia sempervirentia. 
Q. Wislizeni,18 myrtifolia.9 
II, ANDROGYNE, A. DeC.: Amenta mascula erecta, basi flores femineos gerentia ; pollinis cellule fere 0.017 late ; stigmata 
earia. 
Q. densiflora. 
NOTES. 
1. QuERcus LyRATA, Walt., extends as far north as Taxodiwm does, to the banks of the lower Ohio = Illinois. 
s Q MACROCARPA, Michz., is extremely variable in the size of its acorns, and especially in the dep 
the margin of its cup, which sometimes covers the acorn scarcely one-half, usually three-fourths, y [382 (11)] 
occasionally entirely ; the margin is profusely or sparsely fringed. — Throughout the north-west, north of 
the Missouri River, a low scrubby form is found, which might be designated as var. depressa, as it is undoubtedly the 
obtusiloba B. depressa, Nutt. Gen. 2, 215, which has waitek leaves and much smaller acorns erent the species, but is 
clearly a form of macrocarpa. 
3. Q. Micnauxu, Nutt. Gen. 2, 215, excl. syn. — The figure of Michaux, quoted by Nuttall, refers to Q. bicolor: 
and none of his figures represent our plant. Elliott adopts Nuttall’s name, but Chapman as well as DeCandolle con- 
sider it a form of Prinus. @Q. Prinus was described by Linneus with foliis obovatis utrinque acuminatis, which suffi 
ciently well agrees with all the forms of Prinus proper. Our plant is distinguished by having the leaves omg or 
mostly cordate, at base ; thicker, more leathery, and tomentose, on the lower side ; and the male flowers 10-androus. 
All the forms of Prinus proper have a very deciduous pubescence on the lower side of the leaf, which is acute or 
acutish at base. 
4. Q. Prixvs, Linn., would then comprise Michaux’s varieties, palustris, monticola, and acuminata. 
5. Q. unpuxaTA, Torr., has been treated of in the introduction to this paper; the different forms, there also enu- 
merated, are a. Gambelit (Q. Gambelii, Nutt. and probably Q. Drummondii, Liebm.) ; 8. Gunnisoni (Q. alba, var. Gun- 
