Quercus hypoleucoides

The Mexican willow oak (Quercus hypoleucoides ) is a species of the genus of oaks (Quercus ) in the beech family ( Fagaceae ). The natural range is located in the southwestern United States as well as in northwestern Mexico. Their English common name is Silverleaf oak.

Description

Appearance, bark, terminal bud and leaf

The Mexican willow oak grows as evergreen small tree with stature heights of 6 to 10, rarely up to 18 meters with trunk diameters from 0.25 to 0.38 meters, or often a shrub and then treated with plant height 2-5 meters. It forms a tall trunk and a narrow, inverted - conical canopy with slender branches. The branches have a diameter of 1.5 to 3 millimeters and a white fluffy haired, dark reddish- brown bark. The dark gray to almost black bark is thick with deep cracks.

The several standing together end buds are reddish - brown or light - brown coconut and with a diameter of 2.5 to 4.5 mm egg-shaped with a pointed top. The bud scales are bare with ciliated edge and sometimes a tuft of hair on the upper end.

The alternate arranged on the branches leaves are divided 5 to 10 inches long and in petiole and leaf blade. 1.5 to 13 mm long petiole with dense coat fluffy. The simple, leathery leaf blade is at a length of 4.5 to 12 inches and a width of 1.5 to 4 inches narrow - ovate to ovate, narrow -oblong, lanceolate, oblong- lanceolate or elliptic with a wedge-shaped or rounded and pointed Spreitenbasis or tapered at the top. The strongly recurved leaf margin is entire or at the front of sawn with up to eleven points. The leaf blade is initially light red, later yellow-green color. The shiny yellow-green or dark green, much wrinkled upper leaf surface is sparse with stellate hairs ( trichomes ) covered or bare and the underside tight tan, white, hairy silvery woolly. The dropping of the Altblätter happens during the sprouting of new leaves in the spring.

Inflorescence, flower and fruit

The flowering time is in the spring from April to May and occurs simultaneously with the foliation. The Mexican willow oak is monoecious getrenntgeschlechtig ( monoecious ). Many male flowers are yellow - green, drooping, long, kitten -like inflorescences. The male flowers have four to six stamens. The female flowers are single or few in very short racemes in the leaf axils.

The acorns are individually and seated in the normal case or have a short stalk on the branches. The deep cup- to cup-shaped fruit cup, cupula called with a height from 4.5 to 7 mm and a diameter of 6 to 13 mm, enclosing more than one third of the glans. The cupula is fluffy inside to fuzzy hairy, hairy outside, more or less dense fluffy and it has been pushed, blunt scales. The bare acorns are at a length of 8 to 16 mm and a diameter of 5 to 10 millimeters ellipsoid to oblong. The acorns mature in early fall usually in the same growing season after fertilization, sometimes only in the second year.

Occurrence

The Mexican willow oak is common in the southwestern United States and northern Mexico. In the U.S. there are localities in Arizona, New Mexico and Texas. It grows at altitudes from 1800 to 2700 meters. It prefers moist pine forests and populated slopes of canyons or thrives on ridges. At lower altitudes the Mexican willow oak grows as a shrub. It thrives in USDA climate zones 7-8, so it is not very frost hardy.

System

The first description of Quercus hypoleucoides was in 1932 by Aimée Antoinette Camus in Bulletin du Muséum d' Histoire Naturelle, Sér. 2, 4, p 124 are synonyms for Quercus hypoleucoides A.Camus: Quercus hypoleuca Engelm. nom. illeg. , Quercus confertifolia Bonpl.

Quercus hypoleucoides belongs to the section of red oak ( Lobatae ) from the subgenus Quercus in the species of oaks (Quercus ).

Quercus hypoleucoides forms hybrids with Quercus gravesii ( = Quercus × inconstans EJPalmer, syn. Quercus livermorensis CHMuller ) and also with Quercus shumardii.

Use

The Mexican willow oak is used due to their unusual leaves in warm regions as an ornamental plant.

The use of firewood is assumed.

Swell

• Kevin C. Nixon: Quercus: Quercus hypoleucoides A. Camus, Silverleaf oak - text the same online as printed work, In: Flora of North America Editorial Committee ( eds.): Flora of North America North of Mexico, Volume 3 - Magnoliidae and Hamamelidae, Oxford University Press, New York and Oxford, 1997. ISBN 0-19-511246-6 ( Description section )