POLYGONACEAE Juss.
Family of herbaceous plants, some shrubs and a few trees, composed of about 59 genera and 1,380 species, of cosmopolitan Distribution. Most genera are from temperate regions, but some are tropical or subtropical. In North Africa it is represented by various genera, but only Calligonum has trees and shrub species.
However, we should also mention Atraphaxis L., that presents a curious subshrub A. spinosa L. (Ara.: Serra, saras), very woody, spinescent, barely 30 cm in height (although on good soils and light grazing can reach up to 50(70) cm); sheets (0.3-1.2 × 0.2-1 cm) oval-elliptical, slightly fleshy, flat or with a slightly revolute margin, subsessile; flowers with 4 whitish perianth parts, the 2 internal parts larger and more showy, persistent, turning scarious and pink-purple as they surround the small fruit (ovoid, 3-4 mm) in a kind of samara. The species grows in dry areas from Egypt to Mongolia, var. sinaica is present in NE Egypt, Palestine and the Arabian Peninsula. In the Red List of vascular plants of Egypt (Flora Aegyptiaca Vol 1, 2000) it is listed as “Vulnerable”.
Key to genera
1 Trees and shrubs not spinescent, with few and minute leaves (up to 5 mm long), ephemeral Calligonum
1 Subshrub strongly spinescent, with branches covered by leaves, larger (up to 120 mm long), persistent Atraphaxis
Updated by: F. Alcaraz & J. Charco.