Quercus macrocarpa

Michaux

Hist. Chênes Amér., plates 2, 3. 1801.

Common names: Burr oak mossy-cup oak chêne &agrave gros fruits
EndemicIllustrated
Synonyms: Quercus macrocarpa var. depressa (Nuttall) Engelmann Quercus mandanensis
Treatment appears in FNA Volume 3.

Trees, deciduous, to 30 (-50) m. Bark dark gray, scaly or flat-ridged. Twigs grayish or reddish, 2-4 mm diam., often forming extensive flat, radiating, corky wings, finely pubescent. Buds 2-5 (-6) mm, glabrous. Leaves: petiole (6-) 15-25 (-30) mm. Leaf-blade obovate to narrowly elliptic or narrowly obovate, often fiddle-shaped, (50-) 70-150 (-310) × (40-) 50-130 (-160) mm, base rounded to cuneate, margins moderately to deeply lobed, toothed, deepest sinuses near midleaf (at least in proximal 2/3), sinuses reaching nearly to midrib, longer lobes grading into shallow lobes or merely simple teeth distally, shallower, compound lobes proximally, secondary-veins arched, divergent, 4-5 (-10) on each side, apex broadly rounded or ovate; surfaces abaxially light green or whitish, with minute appressed-stellate hairs forming dense, rarely sparse, tomentum, erect felty hairs absent, adaxially dark green or dull gray, sparsely puberulent to glabrate. Acorns 1-3 on stout peduncle (0-) 6-20 (-25) mm; cup hemispheric or turbinate, (8-) 15-50 mm deep × (10-) 20-60 mm wide, enclosing 1/2-7/8 nut or more, scales closely appressed, laterally connate, broadly triangular, keeled, tuberculate, finely grayish tomentose, those near margins often with soft awns to 5-10 mm or more, forming fringe around nut; nut light-brown or grayish, ovoid-ellipsoid or oblong, (15-) 25-50 × (10-) 20-40 mm, finely puberulent or floccose. Cotyledons distinct. 2n = 24.


Phenology: Flowering in spring.
Habitat: Bottomlands, riparian slopes, poorly drained areas, prairies, usually on limestone or calcareous clays (in nw part of range on dry slopes and ridges, prairies)
Elevation: 0-1000 m

Distribution

V3 397-distribution-map.gif

Man., N.B., Sask., Ont., Que., Ala., Ark., Conn., Ill., Ind., Iowa, Kans., Ky., La., Maine, Md., Mass., Mich., Minn., Mo., Mont., Nebr., N.J., N.Y., N.Dak., Ohio, Okla., Pa., S.Dak., Tenn., Tex., Vt., Va., W.Va., Wis., Wyo.

Discussion

Quercus macrocarpa is one of our most cold-tolerant oak species; it also endures a wide variety of other harsh conditions including poor dry soils and wet, poorly drained, and inundated locations. Putative hybrids with Q. bicolor are common in the northeastern part of its range, where the two species often occur together in wet, poorly drained habitats. The effect of this contact may be partially responsible for morphologic differences across the range of Q. macrocarpa. The large acorns are best developed in the southern part of the range, and a clinal decrease in acorn size and extent of the mossy fringe on the acorn cup seems to occur as one travels from south to north. In the northwest part of its range, Q. macrocarpa varies clinally to smaller, shrubbier forms on bluffs and hillsides, with smaller, less fringed cups, that are the basis of Q. macrocarpa var. depressa (Nuttall) Engelmann and Q. mandanensis Rydberg. These scrubby forms may merit formal recognition after more thorough study; they are treated here as clinal variants of the species. Quercus macrocarpa forms putative hybrids also with Q. alba in the savannah-type regions of the midwest. Putative hybrids with Q. gambelii occur out of the range of Q. macrocarpa.

Quercus macrocarpa is the only oak species native to Montana (in the southeast corner). Wood of Q. macrocarpa is similar to that of Q. alba and produces one of the best and most durable oak lumbers.

Native Americans used Quercus macrocarpa medicinally to treat heart troubles, cramps, diarrhea, Italian itch, and broken bones, to expel pinworms, and as an astringent (D. E. Moerman 1986).

Selected References

None.

Lower Taxa

None.
... more about "Quercus macrocarpa"
ovate +  and rounded +
Kevin C. Nixon +
Michaux +
0.5 cm5 mm <br />0.005 m <br /> (?) +  and 1 cm10 mm <br />0.01 m <br /> (?) +
flat-ridged +
rounded;cuneate +
0.5 cm5 mm <br />0.005 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
0.2 cm2 mm <br />0.002 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
2-6-lobed +
pistillate +, capitate +  and spicate +
Burr oak +, mossy-cup oak +, chêne &agrave +  and gros fruits +
starchy +  and fleshy +
turbinate +  and hemispheric +
20mm +  and 60mm +
multibracteate +, spiny +  and scaly +
Man. +, N.B. +, Sask. +, Ont. +, Que. +, Ala. +, Ark. +, Conn. +, Ill. +, Ind. +, Iowa +, Kans. +, Ky. +, La. +, Maine +, Md. +, Mass. +, Mich. +, Minn. +, Mo. +, Mont. +, Nebr. +, N.J. +, N.Y. +, N.Dak. +, Ohio +, Okla. +, Pa. +, S.Dak. +, Tenn. +, Tex. +, Vt. +, Va. +, W.Va. +, Wis. +  and Wyo. +
0-1000 m +
pistillate +  and staminate +
biennial +, annual +  and maturation +
1-seeded +  and winged +
in groups +  and enclosed +
Bottomlands, riparian slopes, poorly drained areas, prairies, usually on limestone or calcareous clays (in nw part of range on dry slopes and ridges, prairies) +
appressed-stellate +
gray +, dull +  and dark green +
sparsely puberulent +  and glabrate +
minute +
pistillate +, spicate +  and staminate +
tomentulose +  and glabrate +
15 cm150 mm <br />0.15 m <br /> (31 cm310 mm <br />0.31 m <br />) +
13 cm130 mm <br />0.13 m <br /> (16 cm160 mm <br />0.16 m <br />) +
7 cm70 mm <br />0.07 m <br /> (15 cm150 mm <br />0.15 m <br />) +
fiddle--shaped +, obovate +  and narrowly elliptic or narrowly obovate +
arranged +  and alternate +
shallow +
entire +, dentate +  and serrate +
toothed +  and lobed +
1.5 cm15 mm <br />0.015 m <br /> (2.5 cm25 mm <br />0.025 m <br />) +
1 cm10 mm <br />0.01 m <br /> (2 cm20 mm <br />0.02 m <br />) +
grayish +  and light-brown +
2.5 cm25 mm <br />0.025 m <br /> (5 cm50 mm <br />0.05 m <br />) +
floccose +  and puberulent +
1/2 +  and 7/8 +
oblong +  and ovoid-ellipsoid +
2 cm20 mm <br />0.02 m <br /> (4 cm40 mm <br />0.04 m <br />) +
2 cm20 mm <br />0.02 m <br /> (2.5 cm25 mm <br />0.025 m <br />) +
0.6 cm6 mm <br />0.006 m <br /> (2 cm20 mm <br />0.02 m <br />) +
2.5 cm25 mm <br />0.025 m <br /> (3 cm30 mm <br />0.03 m <br />) +
1.5 cm15 mm <br />0.015 m <br /> (2.5 cm25 mm <br />0.025 m <br />) +
Flowering in spring. +
Hist. Chênes Amér., plates +
few-to-many +
tuberculate +
keeled +  and triangular +
reduced +
anastomosing +, branching +  and unbranched +
Endemic +  and Illustrated +
inconspicuous +
distinct +
subulate +  and dilated +
enlarged +
whitish +  and light green +
Quercus macrocarpa var. depressa +  and Quercus mandanensis +
Quercus macrocarpa +
Quercus sect. Quercus +
species +
spheric +  and ovoid terete or angled +
reddish +  and grayish +
0.2 cm2 mm <br />0.002 m <br /> (0.4 cm4 mm <br />0.004 m <br />) +
3,000 cm30,000 mm <br />30 m <br /> (5,000 cm50,000 mm <br />50 m <br />) +
extensive +