FNA: Quercus pacifica vs. Quercus viminea

	Quercus pacifica	Quercus viminea
	Channel Island scrub oak, island scrub oak, Pacific oak	Mexican willow oak, Sonoran oak
Habit	Shrubs, rarely small trees, subevergreen, shrubs to 2 m, trees to 5 m or taller.	Trees, evergreen or drought-deciduous, to 10 m. Twigs brown to dark reddish brown, 2-3 mm diam., sparsely to uniformly pubescent.
Bark	scaly on older branches and trunk.
Twigs	brownish or reddish, minutely puberulent, becoming glabrate and gray with age.
Buds	light or chestnut brown, ovate or globose, 2-3 × 1-2 mm.
Leaves	blade obovate or oblong, planar to moderately convex or undulate, 15-40 × 7-20(-40) mm, base cuneate or rounded, attenuate-decurrent along petiole, margins minutely cartilaginous, entire or with 1-5 irregular teeth on each side, secondary veins obscure, 1-5 on each side, apex blunt or rounded, occasionally subacute with mucronate tip; surfaces abaxially waxy, glandular, with scattered minute, flat, appressed, ± 8-rayed stellate hairs, not obscuring surface, adaxially green, glossy, glabrate or with minute, scattered, stellate hairs.	blade narrowly lanceolate, widest at or proximal to middle, 35-60[-150] × 7-10 mm, base usually rounded or obtuse, often oblique, occasionally somewhat cordate, margins entire with 1 apical awn, apex acute to acuminate; surfaces abaxially glabrous or with prominent tufts of tomentum near base of blade, adaxially glabrous or with pubescence along midrib and scattered on blade.
Acorns	paired or solitary in leaf axil, subsessile, rarely pedunculate in teratological forms; cup hemispheric to turbinate, to 15 mm deep × 20 mm wide, enclosing only 1/4-1/2 nut, scales moderately to heavily tuberculate, irregularly formed; nut light brown, acute-cylindric or fusiform, tapered, (15-)20-30 × (6-)9-15 m, apex acute, glabrate.	(not known within our range) biennial; cup cup-shaped, 5-8 mm high × 8-10 mm wide, covering ca. 1/3 nut, inner surface pubescent, scales with appressed, obtuse tips; nut ovoid, 9-15 × 7-10 mm.
Cotyledons	distinct.
Terminal		buds brown to reddish brown, acutely ovoid, 1.5-2.5 mm, glabrous.

	Quercus pacifica	Quercus viminea
Phenology	Flowering spring.	Flowering spring or summer.
Habitat	Chaparral, oak woodlands, margins of grasslands, understory in closed-cone pine stands	Habitat not specified
Elevation	0-300 m (0-1000 ft)	1500 m (4900 ft)
Distribution	CA [WildflowerSearch map] [BONAP county map]	AZ; Mexico (Chihuahua, Sonora, and southward) [WildflowerSearch map] [BONAP county map]
Discussion	Of conservation concern. Quercus pacifica is endemic on three of the California Channel Islands: Santa Cruz, Santa Catalina, and Santa Rosa. It is not known from the mainland, but it bears a superficial similarity to some of the tree forms that are putative hybrids between Q. engelmannii and Q. cornelius-mulleri in San Diego County. The latter populations, sometimes treated as Q. ×acutidens, differ in having much greater variability in leaf shape; thicker, more leathery leaves; denser abaxial leaf vestiture; much smaller hairs, having more than 10 rays; and variable levels of connation of cotyledons (always distinct in Q. pacifica). Quercus pacifica appears to be most closely related to Q. douglasii, whether by direct descent or by introgression with another species no longer extant on the islands. Quercus ×macdonaldii Greene (as a species) [= Quercus dumosa var. macdonaldii (Greene) Jepson] is a stabilized hybrid complex between Quercus pacifica and Q. lobata Née. The plants tend to be small to moderate trees with leaves that resemble those of Q. lobata; the leaves are much more shallowly lobed and always less than two-thirds the distance from the margin to the midrib. Quercus ×macdonaldii is known from Santa Rosa, Santa Cruz, and Santa Catalina islands. (Discussion copyrighted by Flora of North America; reprinted with permission.)	As with many of the Madrean counterparts of the oak flora, in very dry years trees progressively lose their leaves through the long dry spring and may become virtually leafless by the time the rains come in early summer (R. W. Spellenberg, pers. comm.). In the flora, Quercus viminea is known from a single sterile specimen collected at Red Mountain, Santa Cruz County, Arizona. Recent attempts to find the taxon at this site have been fruitless. The Arizona specimen is similar to specimens from northern Mexico that have small, usually entire, narrowly lanceolate leaves with short petioles. These northern forms appear to grade clinally into larger-leaved southern forms that fit the general description of Q. bolanyosensis Trelease. (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. 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. 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. 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. virginiana, Q. wislizenii
Synonyms	Q. dumosa var. polycarpa
Name authority	Nixon & C. H. Muller: Novon 4: 391. (1994)	Trelease: Mem. Natl. Acad. Sci. 20: 123, plate 222. (1924)
Web links	Local floras: CA Local Web sites: CalFlora, CalPhotos WildflowerSearch iNaturalist (observations) USDA Plants Database LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search	WildflowerSearch iNaturalist (observations) USDA Plants Database LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search

Quercus viminea

Channel Island scrub oak, island scrub oak, Pacific oak

Mexican willow oak, Sonoran oak

Habit

Shrubs, rarely small trees, subevergreen, shrubs to 2 m, trees to 5 m or taller.

Trees, evergreen or drought-deciduous, to 10 m. Twigs brown to dark reddish brown, 2-3 mm diam., sparsely to uniformly pubescent.

Bark

scaly on older branches and trunk.

Twigs

brownish or reddish, minutely puberulent, becoming glabrate and gray with age.

Buds

light or chestnut brown, ovate or globose, 2-3 × 1-2 mm.

Leaves

blade obovate or oblong, planar to moderately convex or undulate, 15-40 × 7-20(-40) mm, base cuneate or rounded, attenuate-decurrent along petiole, margins minutely cartilaginous, entire or with 1-5 irregular teeth on each side, secondary veins obscure, 1-5 on each side, apex blunt or rounded, occasionally subacute with mucronate tip;

surfaces abaxially waxy, glandular, with scattered minute, flat, appressed, ± 8-rayed stellate hairs, not obscuring surface, adaxially green, glossy, glabrate or with minute, scattered, stellate hairs.

blade narrowly lanceolate, widest at or proximal to middle, 35-60[-150] × 7-10 mm, base usually rounded or obtuse, often oblique, occasionally somewhat cordate, margins entire with 1 apical awn, apex acute to acuminate;

surfaces abaxially glabrous or with prominent tufts of tomentum near base of blade, adaxially glabrous or with pubescence along midrib and scattered on blade.

Acorns

paired or solitary in leaf axil, subsessile, rarely pedunculate in teratological forms;

cup hemispheric to turbinate, to 15 mm deep × 20 mm wide, enclosing only 1/4-1/2 nut, scales moderately to heavily tuberculate, irregularly formed;

nut light brown, acute-cylindric or fusiform, tapered, (15-)20-30 × (6-)9-15 m, apex acute, glabrate.

(not known within our range) biennial;

cup cup-shaped, 5-8 mm high × 8-10 mm wide, covering ca. 1/3 nut, inner surface pubescent, scales with appressed, obtuse tips;

nut ovoid, 9-15 × 7-10 mm.

Cotyledons

distinct.

Terminal

buds brown to reddish brown, acutely ovoid, 1.5-2.5 mm, glabrous.

Quercus pacifica

Quercus viminea

Phenology

Flowering spring.

Flowering spring or summer.

Habitat

Chaparral, oak woodlands, margins of grasslands, understory in closed-cone pine stands

Habitat not specified

Elevation

0-300 m (0-1000 ft)

1500 m (4900 ft)

Distribution

[WildflowerSearch map]

[BONAP county map]

AZ; Mexico (Chihuahua, Sonora, and southward)

[WildflowerSearch map]

[BONAP county map]

Discussion

Of conservation concern.

Quercus pacifica is endemic on three of the California Channel Islands: Santa Cruz, Santa Catalina, and Santa Rosa. It is not known from the mainland, but it bears a superficial similarity to some of the tree forms that are putative hybrids between Q. engelmannii and Q. cornelius-mulleri in San Diego County. The latter populations, sometimes treated as Q. ×acutidens, differ in having much greater variability in leaf shape; thicker, more leathery leaves; denser abaxial leaf vestiture; much smaller hairs, having more than 10 rays; and variable levels of connation of cotyledons (always distinct in Q. pacifica). Quercus pacifica appears to be most closely related to Q. douglasii, whether by direct descent or by introgression with another species no longer extant on the islands.

Quercus ×macdonaldii Greene (as a species) [= Quercus dumosa var. macdonaldii (Greene) Jepson] is a stabilized hybrid complex between Quercus pacifica and Q. lobata Née. The plants tend to be small to moderate trees with leaves that resemble those of Q. lobata; the leaves are much more shallowly lobed and always less than two-thirds the distance from the margin to the midrib. Quercus ×macdonaldii is known from Santa Rosa, Santa Cruz, and Santa Catalina islands.

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

As with many of the Madrean counterparts of the oak flora, in very dry years trees progressively lose their leaves through the long dry spring and may become virtually leafless by the time the rains come in early summer (R. W. Spellenberg, pers. comm.).

In the flora, Quercus viminea is known from a single sterile specimen collected at Red Mountain, Santa Cruz County, Arizona. Recent attempts to find the taxon at this site have been fruitless. The Arizona specimen is similar to specimens from northern Mexico that have small, usually entire, narrowly lanceolate leaves with short petioles. These northern forms appear to grade clinally into larger-leaved southern forms that fit the general description of Q. bolanyosensis Trelease.

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

Source

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. 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. 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. 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. virginiana, Q. wislizenii

Synonyms

Q. dumosa var. polycarpa

Name authority

Nixon & C. H. Muller: Novon 4: 391. (1994)

Trelease: Mem. Natl. Acad. Sci. 20: 123, plate 222. (1924)

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).

Choose a data source: Flora of North America

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Quercus pacifica

Quercus viminea

Quercus pacifica

Quercus viminea