Mexican willow oak

Mexican willow oak
Systematics
	Eurosiden I
Order :	Beech-like (Fagales)
Family :	Beech family (Fagaceae)
Subfamily :	Quercoideae
Genre :	Oak trees ( Quercus )
Type :	Mexican willow oak
Scientific name
	Quercus hypoleucoides
	A. Camus

The Quercus Hypoleucoides ( Quercus hypoleucoides ) is a plant from the genus of oak ( Quercus ) within the family of the Fagaceae (Fagaceae). The natural range is in the southwestern USA and northwestern Mexico. Its common name is silverleaf oak .

description

Appearance, bark, terminal bud and leaf

The Mexican willow oak grows as an evergreen , small tree with heights of 6 to 10, rarely up to 18 meters with trunk diameters of 0.25 to 0.38 meters, or often as a shrub and then with heights of 2 to 5 meters. It forms a high trunk and a narrow, inverted-conical tree crown with slender branches. The twigs have a diameter of 1.5 to 3 millimeters and a white, downy, hairy, dark reddish-brown bark . The dark gray to almost black bark is thick with deep cracks.

The terminal buds that stand together are reddish-brown or light coconut-brown and, with a diameter of 2.5 to 4.5 millimeters, are egg-shaped with a pointed upper end. The bud scales are bare with a ciliate border and sometimes a tuft of hair on the upper end.

The alternate leaves arranged on the branches are 5 to 10 centimeters long and divided into petioles and leaf blades. The 1.5 to 13 millimeter long leaf stalk is densely hairy and downy. The simple, leathery leaf blade is 4.5 to 12 centimeters long and 1.5 to 4 centimeters wide, narrow-ovate to ovate, narrow-oblong, lanceolate, oblong-lanceolate or elliptical with a wedge-shaped or rounded blade base and pointed or pointed upper end. The strongly recurved leaf margin is entire or sawn in the front area with up to eleven points. The leaf blade is initially light red, later yellow-green in color. The glossy yellow-green or dark green, clearly wrinkled upper side of the leaf is sparsely covered with star hairs ( trichomes ) or glabrous and the underside is densely tan-colored, white, silvery woolly haired. The old leaves are shed when the new leaves emerge in spring.

Inflorescence, flower and fruit

The flowering time is in spring from April to May and takes place at the same time as the leaves shoot. The Mexican willow oak is single-sexed ( monoecious ). Many male flowers are in yellow-green, pendulous, long, cat-shaped inflorescences . The male flowers have four to six stamens . The female flowers are found individually or in small numbers in very short inflorescences in the leaf axils.

The acorns are usually solitary and sitting or have a short stem on the branches. With a height of 4.5 to 7 millimeters and a diameter of 6 to 13 millimeters deep, the bowl-shaped or cup-shaped fruit cup , called cupula, encloses a maximum of one third of the glans. The cupula is downy to flaky on the inside, more or less densely haired on the outside and it has pressed, blunt scales. The bald acorns are ellipsoidal to oblong with a length of 8 to 16 millimeters and a diameter of 5 to 10 millimeters. The acorns usually ripen in early autumn in the same growing season after fertilization, sometimes not until the second year.

Distribution map according to USGS

Occurrence

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

Systematics

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

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

Quercus hypoleucoides forms hybrids with Quercus gravesii (= Quercus × inconstans E.J. Palmer , Syn .: Quercus livermorensis C.H. Muller ) and also with Quercus shumardii .

use

The Mexican willow oak is used as an ornamental plant in warm areas because of its unusual leaves .

Use as firewood is assumed.

swell

Kevin C. Nixon: Quercus : Quercus hypoleucoides A. Camus, Silverleaf oak - same text online as the printed work , In: Flora of North America Editorial Committee (ed.): 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)