- Leathery texture of leaves
- Juvenile acorn
- Mature acorns
- Shown with Garrya buxifolia
Leather Oak | |
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var. durata | |
Scientific classification | |
Kingdom: | Plantae |
Clade: | Tracheophytes |
Clade: | Angiosperms |
Clade: | Eudicots |
Clade: | Rosids |
Order: | Fagales |
Family: | Fagaceae |
Genus: | Quercus |
Subgenus: | Quercus subg. Quercus |
Section: | Quercus sect. Quercus |
Species: | Q. durata |
Binomial name | |
Quercus durata | |
Natural range of Quercus durata | |
Synonyms [2] | |
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Quercus durata, commonly known as leather oak, is a species of oak endemic to California, common in the Coast Ranges and the foothills of the Sierra Nevada. The common name "leather oak" is derived from the leathery texture on the lop of its leaves. Taxonomically it is placed in the white oak group (subgenus Quercus, section Quercus).
As described by English horticulturist and botanist Theodore Payne, leather oak is "A rather low spreading shrub with rigid branches, foliage rich deep green. Desirable for hillside planting." [3] Quercus durata is a short species of oak generally growing to 1–2 metres (3+1⁄2–6+1⁄2 feet) in diameter with a height of about 0.5–1.5 m (1+1⁄2–5 ft). In more extreme cases they have been known to grow to be 3–4 m across. The gray or yellowish twigs have scaly bark and are about 1–3 centimetres (1⁄2–1+1⁄4 inches) in diameter with the trunk diameter reaching 4–5 cm; the branches can be densely or sparsely distributed. The buds are smooth brown or reddish brown ovals.
The leaf blades are cupped or convex, rarely somewhat planar; their dimensions are 1.5–3 cm long and 1–1.5 cm broad densely or sparsely distributed along the branches while the margins of the leaves can be entirely or irregularly toothed. [4] The adaxial (upper) surface of the leaves are greenish or yellowish with short semi-erect hairs; the secondary veins are obscure, dense or scattered. The abaxial (lower) surface of the leaves are covered with erect rayed hairs 1–4 millimetres (1⁄16–3⁄16 in) in length that are felty to the touch with prominent secondary veins.
The acorns of the leather oak can be found solitary or paired at the end of a small stalk; the cup which encloses up to half of the nut is reddish or yellowish with a scaly texture. The nut itself is cylindrical, measuring 1.5–2.5 cm in diameter and 1–2.5 cm long, the apex can be rounded or obtuse. [5] [6] Because leather oak is a species of white oak, its acorns mature in about 6 months, are hairless inside the acorn shell, and are sweet or slightly bitter tasting; the shell is mildly toxic. It is a dicot that flowers in the spring, typically April or May. [7]
The largest differentiation between the morphology of the durata variant and the gabrielensis variant is found in the leaves. The leaves of the gabrielensis variant are not as densely crowded and still commonly have regular teeth along the edges. The upper surfaces are colored a darker green and are glossy, glabrous (without hair) and usually moderately cupped or sub-planar. The lower surface of the leaves have persistently wooly surfaces with hairs 2–4 mm in length. [8] [9]
The range of Quercus durata stretches from Shasta County in Northern California to the bottom of the South Coast Range in Santa Barbara County. The most common variant is found in foothill woodlands and chaparral ecosystems at elevations between 30 and 1,570 m (100 to 5,150 ft). [7] It is especially abundant in Sargent cypress ( Hesperocyparis sargentii ) woodlands which can be found in portions of Mendocino, Sonoma, San Mateo, Santa Clara, Monterey, San Benito, San Luis Obispo and Santa Barbara counties as well as the San Francisco Bay region. [4] In more sheltered, inland areas like MacNab cypress ( Hesperocyparis macnabiana ) woodlands this shrub can extend into riparian zones where summer fogs persist. [10] Q. durata is well suited for ultramafic soils which are reddish and typically nutrient poor, having abundant nickel, magnesium, and chromium content while lacking calcium. Ultramafic chaparral communities are found below 500 m (1,500 ft) from Santa Barbara County north through the North Coast Ranges and also within the foothills of the Sierra Nevada and portions of the California Central Valley. Here, Q. durata can be found with shrubs including chamise ( Adenostoma fasciculatum ), coffeeberry ( Frangula californica ), buckthorn ( Rhamnus crocea ) and toyon ( Heteromeles arbutifolia ). Scattered occurrences of canyon live oak and coast live oak are also found here. In cases outside of serpentine environments, leather oaks typically occur as isolated individuals within a backdrop of plant associations dominated by California scrub oak (Q. berberidifolia) and interior live oak (Q. wislizeni). [4] The climate in Q. durata habitat is characterized by 41 to 170 cm (16 to 67 in) of annual precipitation during a wet season of 3 to 8 months, temperatures range from a December low of 30 °F to a July high of 96 °F. It can sustain life in soil pH between 5.5 and 8.3. [7]
Based on controlled studies done at Jasper Ridge Biological Preserve the harsh environment of Q. durata limits species re-establishment after forest clearing or in colonization of grassland at chaparral-prairie boundaries. Low summer precipitation, high solar insolation, and herbivory are the basis for this difficulty rather than germination rates. [11]
Occurs at elevation 370–2,290 m (1,215–7,515 ft) as a limited distribution taxon in the San Gabriel Mountains within the San Bernardino and Los Angeles counties. The dry, exposed slopes of the San Gabriels stretching from La Cañada to Pomona are covered in a chaparral with non-serpentine soils suitable for Quercus durata var. gabrielensis. [4] [5] The precipitation, temperature, and soil pH ranges for the gabrielensis variant are much narrower than the common variant sitting at approximately 24-47 in of water annually, 44-51 °F, and 6.4 to 6.9 pH respectively. The December low in this region is 36 °F while the July high can reach 90 °F. [8]
When located close to species of pine, Q. durata can be infected by certain species of heteroecious rust fungi ( cronartium). [12] Leather oak is a host for the parasitic Gall Wasp Cynips washingtonensis, who deposits its larvae onto the plant and construct small 1–3 mm spherical galls on Q. durata as well as valley oak (Q. lobata) and coastal sage scrub oak (Q. dumosa). These galls appear in early spring and can be quite numerously attached to twigs and leaves; the gall is typically engulfed in a mass of velvety hairs. Crystalline gall wasp larvae ( Andricus crystallinus) can form irregularly shaped, pallidal galls that agglomerate into masses, with individual galls being between 8–9 mm in length. [13]
It is also a host plant for the sleepy duskywing (Erynnis brizo) butterfly, which sometimes feeds on nectar, and the Pacific tent caterpillar moth (Malacosoma constricta). [14] Birds and small mammals can be attracted to the acorns.
In a study done by Narvaez et al. in 2000 with a group of goats and sheep at the Hopland Research and Extension Center, it was found that for animals employed in vegetation management programs across grass woodlands and chaparral ecosystems nutritional quality and intake levels of Q. durata and Adenostoma fasciculatum foliage were low and demonstrated a need for diet supplementation in livestock performing as part of vegetation control programs. [15]
Native Americans peoples used leather oak as a source of food and medicine. After leaching tannins from the acorns, they would mash it into a nutritional mush that in tandem with other oak products was a staple in their diets. One prevalent leaching method was to place raw acorns in a cloth pouch and leave it in a stream for several weeks to break down. In modern times the mulch from the leather oak is applied to gardens for its efficacy in repelling slugs and grubs. After pupation the oak's gall extracts can be used in tannins and dyes. [16]
Chaparral is a shrubland plant community and geographical feature found primarily in the U.S. state of California, in southern Oregon, and in the northern portion of the Baja California Peninsula in Mexico. It is shaped by a Mediterranean climate and infrequent, high-intensity crown fires. Chaparral features summer-drought-tolerant plants with hard sclerophyllous evergreen leaves, as contrasted with the associated soft-leaved, drought-deciduous, scrub community of coastal sage scrub, found often on drier, southern facing slopes within the chaparral biome. Three other closely related chaparral shrubland systems occur in central Arizona, western Texas, and along the eastern side of central Mexico's mountain chains (mexical), all having summer rains in contrast to the Mediterranean climate of other chaparral formations. Chaparral comprises 9% of California's wildland vegetation and contains 20% of its plant species. The name comes from the Spanish word chaparro, which translates to "place of the scrub oak".
Quercus kelloggii, the California black oak, also known as Kellogg oak, is an oak in the red oak section, native to western North America. Although genetically separated from them for more than 20 million years, its leaves are remarkably similar in appearance to several other members of the red oak section including the red oak and the black oak found in eastern and central North America.
Quercus agrifolia, the California live oak, or coast live oak, is a highly variable, often evergreen oak tree, a type of live oak, native to the California Floristic Province. It may be shrubby, depending on age and growing location, but is generally a medium-sized tree. It grows west of the Sierra Nevada mountain range from Mendocino County, California, south to northern Baja California in Mexico. It is classified in the red oak section of oaks.
Quercus wislizeni, known by the common name interior live oak, is an evergreen oak, highly variable and often shrubby, found in many areas of California in the United States continuing south into northern Baja California in Mexico. It generally occurs in foothills, being most abundant in the lower elevations of the Sierra Nevada, but also widespread in the Pacific Coast Ranges—where since 1980 it has been known as a separate species Quercus parvula—and the San Gabriel Mountains. It was named for its collector, Friedrich Adolph Wislizenus (1810–1889).
Quercus douglasii, known as blue oak, is a species of oak endemic to California, common in the Coast Ranges and the foothills of the Sierra Nevada. It is California's most drought-tolerant deciduous oak, and is a dominant species in the blue oak woodland ecosystem. It is occasionally known as mountain oak and iron oak.
Quercus coccifera, the kermes oak, is an oak bush in the Quercus section Cerris. It is native to the Mediterranean region and Northern African Maghreb, south to north from Morocco to France and west to east from Portugal to Cyprus and Turkey, crossing Spain, Italy, Libya, Balkans, and Greece, including Crete. The Kermes Oak was historically important as the food plant of the Kermes scale insect, from which a red dye called crimson was obtained. The etymology of the specific name coccifera is related to the production of red cochineal (crimson) dye and derived from Latin coccum which was from Greek κόκκος, the kermes insect. The Latin -fera means 'bearer'.
Adenostoma fasciculatum, commonly known as chamise or greasewood, is a flowering plant native to California and Baja California. This shrub is one of the most widespread plants of the California chaparral ecoregion. Chamise produces a specialized lignotuber underground and at the base of the stem, known as a burl, that allow it to resprout after fire has off burned its stems. It is noted for its greasy, resinous foliage, and its status as one of California's most iconic chaparral shrubs.
Quercus berberidifolia, the California scrub oak, is a small evergreen or semi-evergreen shrubby oak in the white oak section of Quercus. It is a native of the scrubby hills of California, and is a common member of chaparral ecosystems.
Ribes malvaceum, the chaparral currant, is a member of the Grossulariaceae. It is native to California and northern Baja California, where it occurs from sea level to 1,500 metres (4,900 ft), in chaparral, foothill oak woodland, and closed-cone pine forest habitats.
Eriogonum fasciculatum is a species of wild buckwheat known by the common names California buckwheat and flat-topped buckwheat. Characterized by small, white and pink flower clusters that give off a cottony effect, this species grows variably from a patchy mat to a wide shrub, with the flowers turning a rusty color after blooming. This plant is of great benefit across its various habitats, providing an important food resource for a diversity of insect and mammal species. It also provides numerous ecosystem services for humans, including erosion control, post-fire mitigation, increases in crop yields when planted in hedgerows, and high habitat restoration value.
Quercus faginea, the Portuguese oak, is a species of oak native to the western Mediterranean region in the Iberian Peninsula. Similar trees in the Atlas Mountains of northwest Africa are usually included in this species, or sometimes treated as a distinct species, Quercus tlemcenensis. It occurs in mountains from sea level to 1,900 metres above sea level, and flourishes in a variety of soils and climates. Out of all the oak forests in the Iberian Peninsula, the southern populations of Portuguese oak were found to have the highest diversity and endemism of spider species.
Quercus chrysolepis, commonly termed canyon live oak, canyon oak, golden cup oak or maul oak, is a North American species of evergreen oak that is found in Mexico and in the western United States, notably in the California Coast Ranges. This tree is often found near creeks and drainage swales growing in moist cool microhabitats. Its leaves are a glossy dark green on the upper surface with prominent spines; a further identification arises from the leaves of canyon live oak being geometrically flat.
Quercus dumosa is a species of plant in the family Fagaceae, belonging to the white oak section of the oak genus (Quercus). This tree goes by the common names coastal sage scrub oak and Nuttall's scrub oak.
Quercus vacciniifolia, the huckleberry oak, is a member of the Protobalanus section of genus Quercus. It has evergreen foliage, short styles, very bitter acorns that mature in 18 months, and a woolly acorn shell interior.
Quercus sinuatavar. breviloba, commonly called Bigelow oak or Bigelow's oak, is a variety of Quercus sinuata, a species of oak tree that grows in parts of the southern United States and northeastern Mexico. Common names for this taxon are shallow-lobed oak, white shin oak, scaly-bark oak, limestone Durand oak, and shortlobe oak. The less specific common name bastard oak may refer to either of the two varieties of Quercus sinuata, var. sinuata and var. breviloba. Other common names include scrub oak or shin oak, but these names may refer to a number of other low growing, clump forming oak species, subspecies or varieties. For clear differentiation in common reference, American Forests uses Durand Oak to mean Quercus sinuata var. sinuata and Bigelow oak to mean Quercus sinuata var. breviloba, a shrubby variety of Quercus sinuata distinguished in part by its habit of forming clonal colonies in parts of its range.
Quercus cornelius-mulleri is a North American species of oak known by the common name Muller oak, or Muller's oak. It was described to science in 1981 when it was segregated from the Quercus dumosa complex and found to warrant species status of its own. It was named after ecologist Cornelius Herman Muller. It is native to southern California and Baja California, where it grows in chaparral, oak woodlands, and other habitat in foothills and mountains. It can most easily be observed in Joshua Tree National Park and in the woodlands along the western margins of the Colorado Desert in San Diego County, California.
Quercus john-tuckeri is a North American species of oak known by the common name Tucker oak, or Tucker's oak. It is endemic to California, where it grows in the chaparral and oak woodlands of mountain slopes in the western Transverse Ranges, the southernmost Central Coast Ranges, and the margins of the Mojave Desert. The species is named after John M. Tucker, professor of botany (1947–1986) at the University of California at Davis, specialist in Quercus.
Quercus palmeri is a species of oak known by the common name Palmer oak, or Palmer's oak. It is native to California, Baja California, Southern Nevada, and in Arizona through the transition zone to the eastern Mogollon Rim, where it grows in canyons, mountain slopes, washes, and other dry habitats.
Quercus turbinella is a North American species of oak known by the common names shrub oak, turbinella oak, shrub live oak, and gray oak. It is native to Arizona, California, New Mexico, Utah, Colorado, and Nevada in the western United States. It also occurs in northern Mexico.
Quercus pacifica is a species of oak known by the common names island scrub oak, Channel Island scrub oak, and Pacific oak.