White Saxaul Tree

This species is very useful for sand-binding and afforestation. It has been introduced to sand areas of Gansu, Nei Mongol, and Ningxia for this purpose.

Trees small, 1-7 m tall. Bark gray-white; wood hard, brittle; older branches gray-brown or light yellow-brown, usually fissured annular; annual branches pendulous, internodes 0.5-1.5 cm × ca. 1.5 mm. Leaves appressed to branch, scale-like, triangular, apex awned; leaf axil cottony. Flowers borne on dwarf, lateral spurs of previous year's branches; bractlets navicular, ovate, equaling perianth, margin membranous. Perianth segments ovate, apex obtuse or subacute; abaxial wing borne 1/4 of distance from apex, light yellow, flabellate or suborbicular, 4-7 mm wide, obscurely veined, base broadly cuneate to rounded, margin repand or subentire. Disk obscure. Utricle light yellow-brown; pericarp not adnate to seed. Seed ca. 2.5 mm in diam.; embryo spiral, abaxially convex, turbinate, adaxially plane. Fl. May-Jun, fr. Sep-Oct.

Small tree, up to 5 m high, with a stout rugged stem and light grey bark; branches of the preceding year whitish, densely covered with circular cracks; annotinous shoots pale-green, rather rigid, 1-2 mm in diam., usually erect when young, drooping when old; leaves reduced, scale-like, terminating in a straw-coloured cusp, appressed to stem. Flowers solitary in the axils of obtuse, scale-like bracts borne on very short, twigs; bracteoles round-oval, scarious- margined, obtusely carinate, as long as flower; perianth segments obtuse, membranous, winged in fruit near summit; wings suborbicular, or reniform-semiorbicular, usually somewhat twisted, rounded or subcordate at base, with a span of 9-12 mm. Fruit depressed, 2-2.5 mm in diam., scarcely surpassing the winged perianth.

Distribution: Palestine, Jordan, Egypt, Sinai, S. Iraq, Saudi Arabia; Iran to Oman and UAE, Turcomania, Afghanistan, Pakistan (Baluchistan) to China.

Fl. Per.: October-November.

Dunes. N Xinjiang [NE Africa, SC and SW Asia].

Arthrophytum acutifolium (Minkwitz) Minkwitz; A. ammodendron (C. A. Meyer) Litvinov var. acutifolium Minkwitz; A. persicum (Bunge) Savicz-Ryczegorski.

Arthrophytum acutifolium Minkw. in B. Fedschenko, Rast. Turk. 360. 1915. A. arborescens Litv. in Trav. Mus. Bot. Acad. Sc. Petersb. 11: 44. 1913; A. persicum (Bunge ex Boiss. & Buhse) Sawicz in Not. Syst. Herb. Petrop. 5: 45. 1924.