Juglans microcarpa

Juglans microcarpa

Juglans microcarpa is a North American species of the genus walnuts ( Juglans ).

Features

Juglans microcarpa is a shrub or small tree up to 10 m height. The bark is medium gray and furrowed in rather strong. The branches are connected to the distal edge of the leaf scar, in which they stand, notched. You are bald or bounded by a poorly defined entire hairy zone. The cord is light to dark brown. The terminal buds are globose to ovoid short, not flattened and 3 to 5 mm long.

The leaves are pinnate, and 12 to 29 cm long, the petiole 1-3 cm. The 17 to 25 leaflets are lanceolate or narrowly lanceolate and weak to strong sickle-shaped. They are 5.2 to 6.3 cm long and 0.8 to 1.1 cm wide, the leaf margin is serrated in whole or in, the blade tip is acuminate. The underside bears capitate - glandular hairs, often also scattered scales. The axils of the nerves near the base of the leaf are usually, but not always, provided with a distinct tuft of hair. The top is covered with capitate - glandular hairs. The terminal leaflet is usually small.

The male catkins are 3-7 cm long and have a per flower 20 to 25, rarely 35 stamens. The pollen sacs are from 0.8 to 1 mm long. Bloom time is spring ( March-April, rarely to June).

The one to three fruits per inflorescence are spherical, 1.4 to 2.3 cm in size, smooth, and covered with capitate - glandular hairs. The nuts are globose to compressed, 1.1 to 1.7 cm long, grooved and smooth between the furrows.

Dissemination

Juglans microcarpa is native to the U.S. states of Kansas, New Mexico, Oklahoma and Texas, as well as in the Mexican states of Chihuahua, Coahuila and Nuevo Leon. It grows along rivers and streams from 200 to 2000 m above sea level.

System

Juglans microcarpa is placed in the section Rhysocaryon within the genus Juglans. It is closely related Juglans nigra with.

Specimens with large leaflets (up to 9.6 cm long) could be the result of introgression of Juglans major. They are sometimes as a separate variety ( Juglans microcarpa var stewartii (IM Johnston ) WE Manning ) considered and are known only from Mexico. There are also known intermediate forms between Juglans microcarpa and Juglans nigra.

Documents

  • Donald E. Stone: Juglandaceae. In: Flora of North America, Volume 3 (online, English)
  • Walnut Family
  • Juglandaceae
Rosids Fagales Chihuahua (state)
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