Flora of North America species comparison

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Quercus fusiformis

Quercus prinoides

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

dwarf chestnut oak, dwarf Chinkapin oak, dwarf chinquapin oak, scrub chestnut oak
Habit Trees, sometimes shrubs, subevergreen, trees to 25 m, shrubs often forming large clonal stands. Shrubs, deciduous, (0.5-)1-3(-5, 10?) m, sometimes spreading-rhizomatous.
Bark

dark brown or black, scaly.

gray, thin, flaky to papery.
Twigs

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

brownish, 1.5-3(-4) mm diam., sparsely fine-pubescent, soon becoming glabrate, graying in 2d year.
Buds

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

scale margins glabrous or puberulent.

brown to red-brown, subrotund to broadly ovoid, 1-3 mm, apex rounded, very sparsely pubescent.
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 lanceolate to oblanceolate or usually obovate, 40-140 × 20-60(-80) mm, leathery, base truncate to cuneate, margins regularly undulate, toothed or shallow-lobed, teeth usually acute, sometimes rounded, or acute-acuminate, often strongly antrorse, secondary veins usually 5-8(-9) on each side, ± parallel, apex short-acute to acuminate;

surfaces abaxially glaucous or light green, appearing glabrate, with scattered or crowded minute, appressed, symmetric, 6-10-rayed, stellate hairs, adaxially lustrous dark green, glabrate.
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.

solitary or paired, subsessile or on axillary peduncle to 3-8 mm;

cup deeply or shallowly cup-shaped, 9-12 mm deep × 13-17(-22) mm wide, enclosing 1/4-1/3 nut, base rounded, margin usually thin, scales rather tightly appressed, moderately tuberculate, uniformly short gray-pubescent;

nut light brown, oblong to ovoid, (13-)15-20 × 10-13 mm.
Cotyledons

connate.

distinct.

Quercus fusiformis

Quercus prinoides
Phenology Flowering spring. Flowering in 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 Pine barrens, scrublands, forest margins, prairies, and exposed ridges, on deep sands or dry shale, rarely reported on calcareous soils
Elevation 0-1200 m (0-3900 ft) 0-500 m (0-1600 ft)
Distribution
from FNA
OK; TX; Mexico (Coahuila, Nuevo León, and Tamaulipas)
[WildflowerSearch map]
[BONAP county map]
from FNA
AL; AR; CT; GA; IA; IL; IN; KY; MA; MI; MO; NC; NH; NJ; NY; OH; OK; PA; RI; SC; TN; VA; VT; WV; ON
[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.)

Some reports of Quercus prinoides growing in calcareous soils are probably referable to shrub forms of Q. muhlenbergii.

The debate over whether Quercus prinoides is distinct from Q. muhlenbergii has continued for most of the last century. Little doubt can exist that strong genetic differences, as expressed by characteristics of habit, leaf form, and habitat preference, separate the two taxa; the question is merely whether they are best treated as subspecies or varieties or as separate species. Over most of the eastern United States, the two taxa occur sympatrically over broad areas with little immediate contact (syntopy), because Q. muhlenbergii is found on calcareous soils and Q. prinoides occurs on sands (often acidic) and dry shales. Seedlings of Q. prinoides can flower and produce acorns in as few as 3-5 years from planting, when only 20-50 cm, and maintain their dwarf, clonal habit in cultivation. Quercus muhlenbergii begins fruiting as a small tree of 3 m or more in height. Because of these differences, and interdigitating geographic distributions, the two taxa seem to be similar in pattern of variation and interaction to other closely related oak species of eastern North America, and dissimilar in pattern to infraspecific taxa such as we see in Q. sinuata var. sinuata and Q. sinuata var. breviloba. The populations that are difficult to determine are usually small scrubby trees, probably mostly Q. muhlenbergii, stunted because of less than favorable moisture conditions, with or without indications of introgression from Q. prinoides.

Material of Quercus prinoides from Long Island, coastal Massachusetts, Nantucket Island, and Martha's Vineyard has been segregated as Q. prinoides Willdenow var. rufescens Rehder on the basis of vestiture and minor differences in leaf form. These populations have appressed-stellate leaf pubescence abaxially, as throughout the range of the species; in addition they have reddish, erect, fasiculate hairs similar to those found in Q. michauxii. The hairs make the abaxial leaf surface somewhat felty to the touch. Variability in this characteristic and lack of other consistently correlated features preclude taxonomic recognition of Q. prinoides var. rufescens, but this problem is worthy of further investigation.

(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. Quercus
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. 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. 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 Q. prinoides var. rufescens
Name authority Small: Bull. Torrey Bot. Club 28: 357. (1901) Willdenow: in G. H. E. Muhlenberg, Ges. Naturf. Freunde Berlin Neue Schriften 3: 397. (1801)
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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