Quercus pumila |
Fagaceae |
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runner oak, running oak |
beech family, oak family |
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Habit | Shrubs, deciduous or tardily deciduous, to 1 m. Bark gray to dark brown. | Trees or shrubs, evergreen or deciduous, shrubs sometimes rhizomatous. | ||||||||||||||||
Twigs | gray-brown to reddish brown, 1-2 mm diam., sparsely to uniformly pubescent. |
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Leaves | blade oblong to narrowly obovate, 25-100 × 10-33 mm, base acute to rounded, margins entire, revolute, with 1 apical awn, apex acute or obtuse to rounded; surfaces abaxially uniformly gray-brown pubescent, rarely glabrate, adaxially somewhat convex, rugose, glabrous or with scattered hairs along midrib. |
blade lobed or unlobed, pinnately veined, margins serrate, dentate, or entire; surfaces usually pubescent, at least when young, sometimes with scales. |
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Inflorescences | unisexual or androgynous catkins; staminate and androgynous catkins spicate or capitate, rigid, flexible, or lax, consisting of few- to many-flowered clusters, bracts present or absent; pistillate catkins rigid or flexible, with 1-several spicately arranged, rarely solitary, terminal cupules bearing 1-3(-15 or more) pistillate flowers. |
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Staminate flowers | bracteate, bracts often caducous; sepals (3-)4-6(-8); stamens (3-)6-12(-18 or more); petals absent; anthers 2-locular, dehiscing by longitudinal slits, pollen sacs contiguous; pistillode often present and indurate, or vestigial as central tuft of trichomes. |
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Pistillate flowers | calyx of 4-6 distinct or connate sepals; petals absent; pistil 1, 3(-6 or more)-carpellate; ovary inferior, locules as many as carpels; placentation axile; ovules pendulous, 2 in each locule, all but 1 in each pistil usually aborting; styles as many as carpels, distinct to base; stigmas dry; staminodes present or absent. |
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Fruits | nuts, sometimes winged, 1-seeded, subtended or enclosed individually or in groups of 2-3(-15) by scaly or spiny, multibracteate cupule; seed coat membranous; endosperm none; embryo straight, as long as seed; cotyledons fleshy, starchy or oily. |
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Acorns | annual; cup deeply saucer-shaped to turbinate, 5-12 mm high × 10-15 mm wide, covering 1/3-1/2(-2/3) nut, outer surface pubescent, inner surface densely pubescent, scales rarely involute, often tuberculate, tips tightly appressed, acute; nut globose to ovoid or broadly oblong, 9.5-15 × 9-12 mm, glabrate, scar diam. 5-8 mm. |
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Terminal | buds brown to red-brown, ovoid, 2.5-4.5 mm, glabrous or with ciliate scale margins. |
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Winter | buds sessile, with few to many imbricate scales (2 valvate scales enclosing imbricate scales in Castanea); terminal bud present or absent. |
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Quercus pumila |
Fagaceae |
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Phenology | Flowering spring. | |||||||||||||||||
Habitat | Dry sandy soils of savannahs, low ridges and oak-pine scrub, occasionally at margins of poorly drained sites | |||||||||||||||||
Elevation | 0-100 m (0-300 ft) | |||||||||||||||||
Distribution |
AL; FL; GA; MS; NC; SC
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Widespread; often dominant forest trees in temperate; subtropical; and tropical areas; mostly Northern Hemisphere |
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Discussion | Although no hybrid combinations have been formally proposed, D. M. Hunt (1989) has reported evidence of hybridization with Quercus hemisphaerica, Q. incana, Q. myrtifolia, and Q. phellos. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Genera 9, species probably 600-800 (5 genera, 97 species, and numerous hybrids in the flora). In the Western Hemisphere, Fagaceae are found from southern Canada to Colombia; they are absent or infrequent in most of the northern Great Plains and northern Rocky Mountain region. Fagaceae are one of the most important families of Northern Hemisphere woody plants in terms of total biomass and economic use. They are widely used for lumber, firewood, and horticultural plantings; the nuts are often used for animal fodder and, in some species, for human food (particularly Castanea). As dominants in forests, woodlands, and chaparral, native stands of fagaceous trees and shrubs provide optimal wildlife habitat, often harboring an exceptionally diverse insect fauna. Most of the diversity of the family in the Western Hemisphere is concentrated in the genus Quercus, with the greatest number of species in Mexico (at least 125 species), and a secondary area of diversity in the southeastern United States. Polyploidy has not been reported in any natural populations of species of Fagaceae. Natural interspecific hybridization is common in the family, particularly in Quercus, and also in Castanea and Lithocarpus. The most important diagnostic feature of Fagaceae is the cupule, which occurs as the cup or cap of the acorn in Quercus and Lithocarpus and the spiny bur that surrounds the fruits of Castanea and Chrysolepis. The cupule is sometimes referred to as an involuc involucre, however, is made up of bracts, while the cupule has been shown to be a complex structure that is interpreted as an indurated, condensed, partial inflorescence formed by fusion of stem axes with several orders of branching, bearing bracts that are modified as scales and/or spines (see B. S. Fey and P. K. Endress 1983). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 3. | FNA vol. 3, p. 436. | ||||||||||||||||
Parent taxa | Fagaceae > Quercus > sect. Lobatae | |||||||||||||||||
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Name authority | Walter: Fl. Carol., 234. (1788) | Dumortier | ||||||||||||||||
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