Juglans major

Juglans major

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

Features

Juglans major is a 5 to 18 m tall tree and sometimes makes several tribes. The bark is light to medium gray and a checkerboard pattern divided into small plates. The pith of the branches is brown. The terminal buds small ovoid or conical, flattened and 4-7 mm long.

The leaves are 18-38 cm long, of the leaf stalk 3 to 6 cm. The leaflets are 9-15 lanceolate to lanceolate - ovate, symmetrical or sickle-shaped, 6.5 to 10.5 cm long and 1.5 to 3.4 cm wide. The leaf margin serrate, the tip acuminate narrow. The lower leaf surface is covered with capitate - glandular hairs, with single or two-to four-jet hair tufts and often with scattered scales. In the nerve axils often are tufts of hair. On the upper leaf surface sit capitate - glandular hairs, sometimes scattered tufts of hair, the top verkahlt later. The terminal leaflet is usually small or absent.

The male catkins are 5-8 cm long. Each flower has 20-40 stamens. The pollen sacs are 1.2 to 1.4 mm long.

One to three fruits are formed per inflorescence, which are approximately spherical or short ovate and 2 to 3.5 cm in size. The surface is smooth and densely covered with capitate - glandular hairs and shield-shaped scales. The nuts are globose to ovoid, 1.8 to 2.7 cm in size, deeply furrowed longitudinally. The surface between the furrows is smooth.

Dissemination

Juglans major is native to the southern United States and Mexico. The trees grow along rivers and on rocky ravine locations in 300 m to 2,100 m above sea level.

System

Juglans major is provided in the section Rhysocaryon within the genus Juglans. It is closely related Juglans nigra and Juglans microcarpa with.

Within the species, two varieties are distinguished:

  • Juglans major var major is the nominate form with the features described above.
  • Juglans major var glabrata W. E. Manning: The leaves are larger, less hairy, the fruit and the nuts are larger. It solves the nominate in the south, from about the 25th degree of latitude, from.

Documents

  • Donald E. Stone: Juglandaceae. In: Flora of North America, Volume 3 (online)
  • Wayne E. Manning: The genus Juglans in Mexico and Central America. Journal of the Arnold Arboretum, Volume 38, 1957, pp. 121-150.
Rosids Fagales John Torrey
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