Flora of North America species comparison

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Quercus fusiformis

Quercus marilandica

escarpment live oak, live oak, plateau oak, Texas live oak

blackjack oak
Habit Trees, sometimes shrubs, subevergreen, trees to 25 m, shrubs often forming large clonal stands. Trees, deciduous, to 15 m. Bark almost black, with irregular or rectangular blocks, inner bark orangish.
Bark

dark brown or black, scaly.

Twigs

light gray, 1.5-3 mm diam., tomentulose, tomentulum often persistent in age.

ashy brown, (1-)2-4(-5) mm diam., pubescent to tomentose.
Buds

reddish or dark brown, subglobose or ovate, 1.5-3 mm;

scale margins glabrous or puberulent.

Leaves

blade oblong-elliptic to narrowly ovate or lanceolate, sometimes obovate, ± planar, (10-)35-90(-150) × (15-)20-40(-85) mm, base rounded to truncate or cordate, rarely cuneate, margins minutely revolute or flat, entire or irregularly 1-3 toothed on each side, teeth mucronate (rarely spinose in suckers or juveniles), secondary veins obscure, 8-10 on each side, apex obtuse-rounded or acute;

surfaces abaxially whitish or glaucous, densely covered with minute, appressed, fused-stellate hairs, light green and glabrate in shade leaves, adaxially dark or light green, glossy, glabrous or with minute, scattered, stellate hairs.

blade obovate to obtrullate, (50-)70-200 × (40-)70-200 mm, base rounded or cordate, blade not decurrent, margins with 3-5 shallow, often very broad lobes and 3-10 awns, apex acute to obtuse, rarely rounded;

surfaces abaxially scurfy or with scattered pubescence, adaxially glossy, glabrous, secondary veins raised on both surfaces.
Acorns

1-3, on peduncle 3-30 mm;

cup funnel-shaped, hemispheric, or deeply goblet-shaped, 8-15 mm deep × 6-12(-15) mm wide, base often constricted, scales whitish or grayish, thickened basally, keeled, acute-attenuate, tomentulose, tips reddish, glabrous or puberulent;

nut dark brown, often with light brown longitudinal stripes, subfusiform and acute to narrowly barrel-shaped, rarely distally rounded, (17-)20-30(-33) × 8-15 mm, glabrous.

biennial;

cup turbinate, 6-10 mm high × 13-18 mm wide, covering 1/3 nut, outer surface puberulent, inner surface pubescent, scale tips loose, especially at margin of cup, acute or acuminate;

nut broadly ovoid or ellipsoid, 12-20 × 10-18 mm, often striate, glabrate, scar diam. 5-8 mm.
Cotyledons

connate.

Terminal

buds conic or narrowly ovoid-ellipsoid, 5-10 mm, noticeably 5-angled in cross section, tawny pubescent.
[r.

c

.
Friesner

1930. J. W.
Duffield

(1940) suggested that Friesner was counting bivalents;

if so, then 2n = 24, consistent with all other reports for Quercus.]
2n

= 12.

Quercus fusiformis

Quercus marilandica
Phenology Flowering spring. Flowering spring.
Habitat Hills, grasslands, scrublands, open woodlands, oak-juniper woodland, and margins of thorn scrub, often on limestone or deep calcareous loams, sometimes on granular sand or gravel Poor shallow soils of glades, barrens and flatwoods, disturbed fields, rocky outcrops, and dry ridges
Elevation 0-1200 m (0-3900 ft) 0-900 m (0-3000 ft)
Distribution
from FNA
OK; TX; Mexico (Coahuila, Nuevo León, and Tamaulipas)
[WildflowerSearch map]
[BONAP county map]
from FNA
AL; AR; DC; DE; FL; GA; IA; IL; IN; KS; KY; LA; MD; MO; MS; NC; NE; NJ; NY; OH; OK; PA; SC; TN; TX; VA; WV
[WildflowerSearch map]
[BONAP county map]
Discussion

The difficulty in distinguishing Texas populations of Quercus fusiformis from Q. virginiana is reflected in a variety of taxonomic treatments, including reducing Q. fusiformis to varietal rank under Q. virginiana. The latter disposition is problematic, however, because Q. fusiformis in northeastern Mexico is amply distinct from Q. virginiana and appears to be more closely related to Q. brandegei Goldmann, an endemic of Baja California, Mexico. Thus, here we assume that the intergradation of Q. virginiana and Q. fusiformis is a result of secondary contact, and is not primary clinal variation. Under this interpretation, Q. virginiana in typical form extends into Texas only as far west as the Brazos River drainage along the coast from there to the escarpment of the Edwards Plateau; most populations elsewhere are either intermediate between the two species or show greater affinity with Q. fusiformis. On the Edwards Plateau, the live oak populations are small trees forming rhizomatous copses (shinneries) and having mostly acute acorns.

Populations of live oak on deep sands in south Texas differ from typical Quercus fusiformis in having broader, more rounded leaves, often with the secondary veins somewhat impressed abaxially, and relatively blunt, barrel-shaped acorns. These characteristics suggest introgresion from the Mexican-Central American species Q. oleoides Schlechtendal & Chamisso, which in its typical form reaches north only as far as southern Tamaulipas, Mexico. The name Q. oleoides var. quaterna C. H. Muller has been applied to what is apparently a shrub form of one of these Q. fusiformis × Q. oleoides hybrids.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Evidence suggests that small trees from the western portion of the range (primarily Texas and Oklahoma) should be recognized as Quercus marilandica Münchhausen var. ashei Sudworth (D. M. Hunt 1989). These trees are characterized by 50-70 × 40-60 mm leaf blades with abaxial surfaces gray-tomentose in vein axils.

Quercus marilandica reportedly hybridizes with Q. buckleyi and Q. falcata (E. J. Palmer 1948); and with Q. georgiana, Q. ilicifolia (= Q. ×brittoni W. T. Davis), Q. imbricaria [= Q. ×tridentata (A. de Candolle) Engelmann], Q. incana, Q. nigra, Q. phellos (Q. ×rudkini Britton), and Q. velutina (= Q. ×bushii Sargent). D. M. Hunt (1989) cited evidence of hybridization also with Q. arkansana, Q. hemisphaerica, Q. laevis, Q. laurifolia, Q. myrtifolia, Q. palustris, and Q. rubra.

The Choctaw used Quercus marilandica to ease cramps and to aid in childbirth (D. E. Moerman 1986).

(Discussion copyrighted by Flora of North America; reprinted with permission.)
Source FNA vol. 3. FNA vol. 3.
Parent taxa Fagaceae > Quercus > sect. Quercus Fagaceae > Quercus > sect. Lobatae
Sibling taxa
Q. acerifolia, Q. agrifolia, Q. ajoensis, Q. alba, Q. arizonica, Q. arkansana, Q. austrina, Q. berberidifolia, Q. bicolor, Q. boyntonii, Q. buckleyi, Q. carmenensis, Q. chapmanii, Q. chihuahuensis, Q. chrysolepis, Q. coccinea, Q. cornelius-mulleri, Q. depressipes, Q. douglasii, Q. dumosa, Q. durata, Q. ellipsoidalis, Q. emoryi, Q. engelmannii, Q. falcata, Q. gambelii, Q. garryana, Q. geminata, Q. georgiana, Q. graciliformis, Q. gravesii, Q. grisea, Q. havardii, Q. hemisphaerica, Q. hinckleyi, Q. hypoleucoides, Q. ilicifolia, Q. imbricaria, Q. incana, Q. inopina, Q. intricata, Q. john-tuckeri, Q. kelloggii, Q. laceyi, Q. laevis, Q. laurifolia, Q. lobata, Q. lyrata, Q. macrocarpa, Q. margarettae, Q. marilandica, Q. michauxii, Q. minima, Q. mohriana, Q. montana, Q. muehlenbergii, Q. myrtifolia, Q. nigra, Q. oblongifolia, Q. oglethorpensis, Q. pacifica, Q. pagoda, Q. palmeri, Q. palustris, Q. phellos, Q. polymorpha, Q. prinoides, Q. pumila, Q. pungens, Q. robur, Q. robusta, Q. rubra, Q. rugosa, Q. sadleriana, Q. shumardii, Q. similis, Q. sinuata, Q. stellata, Q. tardifolia, Q. texana, Q. tomentella, Q. toumeyi, Q. turbinella, Q. vacciniifolia, Q. vaseyana, Q. velutina, Q. viminea, Q. virginiana, Q. wislizenii
Q. acerifolia, Q. agrifolia, Q. ajoensis, Q. alba, Q. arizonica, Q. arkansana, Q. austrina, Q. berberidifolia, Q. bicolor, Q. boyntonii, Q. buckleyi, Q. carmenensis, Q. chapmanii, Q. chihuahuensis, Q. chrysolepis, Q. coccinea, Q. cornelius-mulleri, Q. depressipes, Q. douglasii, Q. dumosa, Q. durata, Q. ellipsoidalis, Q. emoryi, Q. engelmannii, Q. falcata, Q. fusiformis, Q. gambelii, Q. garryana, Q. geminata, Q. georgiana, Q. graciliformis, Q. gravesii, Q. grisea, Q. havardii, Q. hemisphaerica, Q. hinckleyi, Q. hypoleucoides, Q. ilicifolia, Q. imbricaria, Q. incana, Q. inopina, Q. intricata, Q. john-tuckeri, Q. kelloggii, Q. laceyi, Q. laevis, Q. laurifolia, Q. lobata, Q. lyrata, Q. macrocarpa, Q. margarettae, Q. michauxii, Q. minima, Q. mohriana, Q. montana, Q. muehlenbergii, Q. myrtifolia, Q. nigra, Q. oblongifolia, Q. oglethorpensis, Q. pacifica, Q. pagoda, Q. palmeri, Q. palustris, Q. phellos, Q. polymorpha, Q. prinoides, Q. pumila, Q. pungens, Q. robur, Q. robusta, Q. rubra, Q. rugosa, Q. sadleriana, Q. shumardii, Q. similis, Q. sinuata, Q. stellata, Q. tardifolia, Q. texana, Q. tomentella, Q. toumeyi, Q. turbinella, Q. vacciniifolia, Q. vaseyana, Q. velutina, Q. viminea, Q. virginiana, Q. wislizenii
Synonyms Q. virginiana var. fusiformis
Name authority Small: Bull. Torrey Bot. Club 28: 357. (1901) Münchhausen: Hausvater 5(1): 253. (1770)
Web links 
Unless otherwise noted, all data comes from the online version of the Flora of North America, who have made most of their content available via a Creative Commons license (CC BY 4.0).



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