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Quercus taxonomy
Quercus michauxii Nutt.
EOL Text
Trees , deciduous, to 20 m. Bark light brown or gray, scaly. Twigs brown or reddish brown, 2-3 mm diam., with sparse spreading hairs or glabrate. Buds reddish brown, ovoid, apex rounded or acute, glabrous or minutely puberulent. Leaves: petiole 5-20 mm. Leaf blade broadly obovate or broadly elliptic, (60-)100-280 × 50-180 mm, base rounded-acuminate or broadly cuneate, margins regularly toothed, teeth rounded, dentate, or acuminate, secondary veins 15-20 on each side, parallel, straight or somewhat curved, apex broadly rounded or acuminate; surfaces abaxially light green or yellowish, felty to touch because of conspicuous or minute, erect, 1-4-rayed hairs, adaxially glabrous or with minute simple or fascicled hairs. Acorns 1-3, subsessile or more often on axillary peduncle to 20-30 mm; cup hemispheric, broadly hemispheric or even short-cylindric, 15-25 mm deep × 25-40 mm wide, enclosing 1/2 nut or more, scales very loosely appressed, distinct to base, gray or light brown, moderately to heavily tuberculate, tips silky-tomentose; nut light brown, ovoid or cylindric, 25-35 × 20-25 mm, glabrous. Cotyledons distinct.
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Numerous fungi and insects damage swamp chestnut oak. The fungi include wood-decaying species of Fomes, Polyporus, and Stereum. Oak leaf blister (Taphrina caerulescens) is sporadic in occurrence, as is oak anthracnose (Gnomonia veneta) (3).
Swamp chestnut oak acorns are attacked by weevils such as Curculio pardalis, Conotrachelus naso, and C. posticatus, which consume the seed. Insect defoliators that attack the swamp chestnut are June beetles (Phyllophaga spp.), orangestriped oakworm (Anisota senatoria), fall cankerworm (Alsophila pometaria), spring cankerworm (Paleacrita vernata), forest tent caterpillar (Malacosoma disstria), yellownecked caterpillar (Datana ministra), variable oakleaf caterpillar (Heterocampa manteo), and the redhumped oakworm (Symmerista canicosta).
Borers that attack healthy trees are the red oak borer (Enaphalodes rufulus) in cambium and outer sapwood; carpenterworms (Prionoxystus spp.), in heartwood and sapwood; and the Columbian timber beetle (Corthylus columbianus), in the sapwood. Those attacking weakened trees include the twolined chestnut borer (Agrilus bilineatus), in cambium; and the tilehorned prionus (Prionus imbricornis), in roots. Dying trees are attacked by the oak timberworm (Arrhenodes minutus) (1).
The golden oak scale (Asterolecanium variolosum) kills reproduction and tops in older trees. The gouty oak gall (Callirhytis quercuspunctata) and homed oak gall (C. cornigera) injure small limbs, while the basswood leafminer (Baliosus ruber) attacks the leaves.
Trees begin to produce seed at about age 20 to 25 and attain their optimum production around age 40. Good seed crops can be expected every 3 to 5 years with poor to fair production the balance of the time. There are about 187 cleaned seeds per kilogram (85/lb), with a range of 77 to 430 (35 to 195) (7). The acorn is very palatable and is eaten by white-tailed deer, wild hogs, and squirrels. Squirrels are perhaps the most helpful animals in disseminating the acorns because they hoard far more than they can actually eat.
Chestnut oak shows a 7 to 10 day delay in budbreak and leaf flush on
sites that have heavy metal (copper, zinc, and lead) enrichment of the
soil. This retarded leaf flush may be used in geobotanical
remote-sensing techniques for mineral detection [3].
Quercus houstoniana C. H. Muller
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| Rights holder/Author | eFloras.org Copyright © Missouri Botanical Garden |
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Flowers of swamp chestnut oak appear about the same time as the leaves, from April to May. Swamp chestnut oak is monoecious. The fruit or acorn is nearly sessile and may be solitary or paired. Its cup is broad based and covers about one-third of the acorn. Scales on the cup are free to the base and are pubescent. Its dimensions are 1.9 to 3.2 cm (0.75 to 1.25 in) wide by 2.5 to 3.8 cm (1 to 1.5 in) long. The acorns ripen and fall during September and October.
Good crops of chestnut oak acorns are infrequent, but when available the
acorns are eaten by numerous upland wildlife species, including
white-tailed deer, squirrels, chipmunks, mice, and wild turkeys [49].
White-tailed deer occasionally browse young oak sprouts, especially the
first year after cutting or burning. The deer only take the top few
inches of the sprout unless it is extremely succulent or other food is
scarce [41].
Small birds and mammals, as well as insects such as bees, use chestnut
oak cavities for nesting. In a survey of 31 oak-hickory (Carya spp.)
stands in the Appalachian Mountains, a disproportionate share of
cavities were in chestnut oak [9].
Isotype for Quercus houstoniana C.H. Mull.
Catalog Number: US 1433275
Collection: Smithsonian Institution, National Museum of Natural History, Department of Botany
Verification Degree: Card file verified by examination of alleged type specimen
Preparation: Pressed specimen
Collector(s): E. J. Palmer
Year Collected: 1917
Locality: San Augustine., San Augustine, Texas, United States, North America
- Isotype: Muller, C. H. 1942. Amer. Midl. Naturalist. 28: 743.
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Fire scar wounds left on surviving trees allow the entry of fungi which
can cause heartwood decay [26]. Butt swelling and bulging are
indications of heartrot. Rot usually starts 4 to 5 years after fire.
The scar gets bigger, moving upward along the trunk about 1.5 feet (0.5
m) in 10 years if a quarter of the tree's circumference is damaged [26].
Fire is less damaging during the tree's dormant season because of
lowered ambient temperatures and the tree's physiological state [31].
Crooked trees may be killed more easily than straight trees if crooked
trees are leaning towards the flames. Also, overstocked stands may
suffer more damage from fire due to reduced vigor and size of
individuals [31]. Fire does not appear to affect acorn crops; however,
dying trees tend to produce a massive crop. Acorns themselves are
easily killed because of high moisture content [31].