Flora of North America species comparison

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Quercus fusiformis

Quercus montana

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

chestnut oak, mountain chestnut oak, rock chestnut oak
Habit Trees, sometimes shrubs, subevergreen, trees to 25 m, shrubs often forming large clonal stands. Trees, deciduous, to 30 m. Bark dark gray or brown, hard, with deep V-shaped furrows.
Bark

dark brown or black, scaly.

Twigs

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

light brown, 2-3(-4) mm diam., glabrous.
Buds

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

scale margins glabrous or puberulent.

light brown, ovoid, (3-)4-6 mm, occasionally apex acute, glabrous.
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 narrowly elliptic or narrowly obovate, (100-)120-200(-220) × 60-100(-120) mm, base subacute or rounded-acuminate, often unequal, margins regularly toothed, teeth rounded or rarely somewhat acute, secondary veins ± parallel, straight or moderately curved, 10-14(-16) on each side, apex broadly acuminate;

surfaces abaxially light green, appearing glabrous but with scattered minute, asymmetric, appressed-stellate hairs and usually visible, larger, simple or fascicled erect hairs along veins, adaxially dark green, glossy, glabrous or with minute, scattered, simple hairs.
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.

1-3, subsessile or on peduncle 8-20(-25) mm;

cup shallowly cup-shaped to hemispheric or deeply goblet-shaped, rim thin, often flared and undulate, helmetlike, 9-15 mm deep × 18-25 mm wide, scales often in concentric or transverse rows, laterally connate, gray, broadly ovate, tips reddish, glabrous;

nut light brown, ovoid-ellipsoid, 15-30 × 10-20(-25) mm, glabrous.
Cotyledons

connate.

distinct.
2n

= 24.

Quercus fusiformis

Quercus montana
Phenology Flowering spring. Flowering mid-late 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 Rocky upland forest, dry ridges, mixed deciduous forests on shallow soils
Elevation 0-1200 m (0-3900 ft) 0-1400 m (0-4600 ft)
Distribution
from FNA
OK; TX; Mexico (Coahuila, Nuevo León, and Tamaulipas)
[WildflowerSearch map]
[BONAP county map]
from FNA
AL; CT; DE; GA; IL; IN; KY; MA; MD; ME; MI; MS; NC; NH; NJ; NY; OH; PA; RI; SC; TN; VA; VT; 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.)

The name Quercus prinus Linnaeus is often applied to this species, particularly in the forestry literature, and in many regional floras. In a number of works, however, Q. prinus has been applied to the species here treated as Q. michauxii. Following the recommendations of J. W. Hardin (1979), because of the persistent confusion in the application of the name Q. prinus and uncertainty regarding the identity of the Linnean type materials, the names Q. montana and Q. michauxii should be used for the two species that have been variously called Q. prinus. Quercus prinus under this interpretation is a name of uncertain position.

The four species of the chestnut oak group in eastern North America (Quercus montana, Q. michauxii, Q. muhlenbergii, and Q. prinoides) are somewhat difficult to distinguish unless careful attention is paid to features of leaf vestiture and fruit and cup morphology. Attempts to identify these species mostly or solely on basis of leaf shape and dentition (as in many other oak species complexes) have resulted in a plethora of misidentified material in herbaria and erroneous reports in the literature. The closely appressed, asymmetric trichomes on the abaxial surface of the mature leaf, in combination with longer simple hairs along the midvein, are unique to Q. montana among North American species of Quercus. Immature leaves and densely shaded leaves sometimes exhibit a more erect trichome that could be confused with the longer, felty hairs of Q. michauxii, so it is important to evaluate mature sun leaves when possible.

(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. 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) Willdenow: Sp. Pl. 4(1): 440. (1805)
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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