Fraxinus dimorpha Coss. & Durieu
F. xanthoxyloides var. dimorfa (Coss. & Durieu) Wenz., F. xanthoxyloides var. dumosa (Carrière) Lingelsh.
Eng.: Atlas ash. Spa.: Fresno del Atlas. Fre.: Frêne de l’Atlas. Ara.: Dardar. Tam.: Tuzzalt, imts, imdes, imtass aslen, taslen, aseln.
Deciduous tree, hermaphrodite, up to 12(15) m in height, irregular in shape, but ± oval or rounded crown. Trunk usually slightly tortuous, thick, short, promptly branching. Bark highly fissured, reticulates, light grey. Branches erect-patent, opposite. Younger branchlets chestnut-green. Buds very dark, black or blackish. Leaves of 2 types: adult leaves in the well developed parts of the tree have 7-11 leaflets (2.5 × 2.1 cm), broadly lanceolate, with slightly acute teeth; leaves in the less developed (shrubby) parts and in buds and new shoots are smaller, with 3-9 leaflets (0.5-2 × 0.3-1.6 cm), ellipsoid, obovate or suborbicular, with slightly pronounced obtuse lobules. Inflorescence appears very early, in small, opposite, sessile and highly condensed umbels. Flowers with a small cupuliform calyx, with 4 or more unequal, acute teeth. Corolla absent. Stamens 2 and pistil with 2 stigmas. Fruit an oblong-spatulate samara with apex obtuse, entire or emarginate.
Flowering:
February to March.
Fruiting:
July to September.
Habitat:
Forests (mainly in cedar and holm oak forests) and thickets in plateaux and mountains, up to 2,500 m in altitude. It seems indifferent to the type of substrate. From semiarid to humid bioclimate, on mesomediterranean and supramediterranean floors.
Distribution:
Endemic to North Africa. Morocco (Middle Atlas, central and eastern High Atlas, eastern Anti-Atlas, mountains, plains and plateaux of eastern Morocco and western Saharan Atlas) and Algeria (Eastern and central Saharan Atlas, massifs of the Aures and Bellezma, Hodna and Great Kabylia).
Observations:
For a long time this species and similar species, F. xanthoxyloides (G.Don) Wall. ex A.DC. (from central and eastern Asia), were considered a single species. Currently, all specimens from North Africa of this Asian species should be assigned to F. dimorfa.
Conservation status:
Rare but widely distributed species. In the IUCN Red List of Threatened Species, it is listed as Endangered (EN) at global level (Rankou et al., 2017). In Algeria it is included in the List of protected non cultivated flora (Executive Decree 12-03 on 4-Jan-2012).