Quercus arkansana

Sargent

Trees & Shrubs 2: 121. 1911.

Common names: Arkansas oak
EndemicIllustrated
Synonyms: Quercus caput-rivuli Ashe
Treatment appears in FNA Volume 3.
Revision as of 07:22, 30 July 2020 by imported>Volume Importer
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Trees, deciduous, to 15 m. Bark black with long rough ridges separated by deep furrows. Twigs 1.5-3 mm diam., gray-pubescent, rarely glabrate. Terminal buds redbrown, ovoid, 2-5 mm, glabrous or with scales somewhat ciliate on margins, especially at apex. Leaves: petiole 5-25 mm, pubescent, rarely glabrate. Leaf-blade rhombic to obovate or obtrullate, 50-150 × 35-100 mm, base acute to cordate, margins entire or with 2-3 shallow lobes and up to 10 awns, apex broadly obtuse to rounded; surfaces abaxially uniformly pubescent to glabrous except for conspicuous axillary tufts of tomentum, veins prominent, adaxially planar or somewhat rugose with a few persistent hairs near base. Acorns biennial; cup thin, shallow goblet to almost saucer-shaped, 5-9 mm high × 10-16 mm wide, covering 1/4-1/2 nut, outer surface puberulent, inner surface sparsely to uniformly pubescent, scale tips appressed, acute; nut broadly ellipsoid to subglobose, 10-15 × 9-15 mm, puberulent, scar diam. 5-10 mm.


Phenology: Flowering spring.
Habitat: An understory tree of well-drained, sandy soils, on ravine heads (pocosins, steepheads)
Elevation: 50-150 m

Distribution

V3 1078-distribution-map.gif

Ala., Ark., Fla., Ga., La., Tex.

Discussion

Quercus arkansana reportedly hybridizes with Q. incana (= Q. ×venulosa Ashe) and Q. nigra (D. M. Hunt 1986; W. H. Duncan and M. B. Duncan 1988). While agreeing that an isotype of the former clearly indicated a relationship to Q. arkansana, E. J. Palmer (1948) questioned the identity of the second parent and noted that venulosa is a homonym of a fossil species. In addition, D. M. Hunt (1989) cited evidence of hybridization with Q. hemisphaerica, Q. laevis, Q. marilandica, Q. myrtifolia, and either Q. falcata or Q. velutina.

Selected References

None.

Lower Taxa

None.
... more about "Quercus arkansana"
broadly obtuse +  and rounded +
Kevin C. Nixon +
Sargent +
furrowed +  and smooth +
acute;cordate +
2-6-lobed +
pistillate +, capitate +  and spicate +
Arkansas oak +
connate +  and distinct +
starchy +  and fleshy +
shallow +
tuberculate +
saucer--shaped +
×10-16 +, 5mm +  and 9mm +
multibracteate +, spiny +  and scaly +
Ala. +, Ark. +, Fla. +, Ga. +, La. +  and Tex. +
50-150 m +
pistillate +  and staminate +
biennial +, annual +  and maturation +
1-seeded +  and winged +
in groups +  and enclosed +
An understory tree of well-drained, sandy soils, on ravine heads (pocosins, steepheads) +
persistent +
pistillate +, spicate +  and staminate +
silky-tomentose +
5 cm50 mm <br />0.05 m <br /> (15 cm150 mm <br />0.15 m <br />) +
rhombic +  and obovate or obtrullate +
arranged +  and alternate +
shallow +
0 (?) +  and 10 (?) +
with 2-3 shallow lobes +  and entire +
toothed +  and entire +
1 cm10 mm <br />0.01 m <br /> (1.5 cm15 mm <br />0.015 m <br />) +
puberulent +
1/4 +  and 1/2 +
broadly ellipsoid +  and subglobose +
0.9 cm9 mm <br />0.009 m <br /> (1.5 cm15 mm <br />0.015 m <br />) +
glabrate +  and pubescent +
0.5 cm5 mm <br />0.005 m <br /> (2.5 cm25 mm <br />0.025 m <br />) +
Flowering spring. +
Trees & Shrubs +
distinct +
few-to-many +
reduced +
0.5 cm5 mm <br />0.005 m <br /> (1 cm10 mm <br />0.01 m <br />) +
anastomosing +, branching +  and unbranched +
Endemic +  and Illustrated +
inconspicuous +
distinct +
linear-spatulate +
abaxially uniformly pubescent +  and glabrous +
Quercus caput-rivuli +
Quercus arkansana +
Quercus sect. Lobatae +
species +
with scales +  and glabrous +
0.2 cm2 mm <br />0.002 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
bristle-tipped +
0.15 cm1.5 mm <br />0.0015 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
glabrate +  and gray-pubescent +