Rhamnus cathartica Linnaeus (1753: 193)

Alijanpoor, Behnaz, Khodayari, Hamed, Assadi, Mostafa, Rahiminejad, Mohammadreza & Mehregan, Iraj, 2021, A taxonomic revision of Rhamnus L. and Atadinus Raf. (Rhamnaceae) in Iran, Phytotaxa 521 (3), pp. 127-158 : 131

1. Rhamnus cathartica Linnaeus (1753: 193) .

Typus —Europa ( L 262-1 image!) .

Description— Trees or shrubs, erect, 2–4 or rarely 1.5 m high. Branches dark grey or greyish brown, pubescent when young, spiny and rarely not spiny, spiny branches mostly alternate and rarely opposite. Leaves green, thin, herbaceous, sometimes pubescent, (1–) 1.5–7.5 cm × (1–) 1.5–3.5 cm, ovate or obovate to elliptic, orbicular or lanceolate, dimorphic or rarely monomorphic in each specimen, fasciculate on scaly branches and alternate on long branches with numerous teeth on margin; base of leaves mostly roundish, cuneate; apex obtuse or rarely acute; lateral nerves curved, alternate, opposite, conspicuous, 3–5 pairs (mostly 3 pairs); petioles 5-16 (-20) mm long. Inflorescence fasciculate. Flowers 4- merous, mostly unisexual, sometimes bisexual, (3–) 4–5 mm long, with 2–4 styles; calyx campanulate, rarely ligulate, with 3 veins, acute, (1–) 1.5–4 mm long, lobes 1–3 mm long; petals 4, sometimes absent, linear and rarely broad, opposite to filament; disk very small; ovary with (2–)3–4 locular and with (2–)3–4 styls; peduncles 3–10 mm long, sometimes pubescent. Fruits a fleshy drupe, mainly spherical, 4–5 mm long, with (2–)3–4 seeds, with (2–)2–4 furrows.

Habitat and distribution — R. cathartica grows in a wide variety of habitats. In Iran, it grows at an altitude of 980–2400 m, between 49° and 54° E and between 36° and 38° N. The species occurs in N to C & W Iran on E, W and S slopes in the forests or shrublands, sometime along the rivers in valleies on rocks and pasture lands. There are different companion species in different habitats, but one species of Crateagus L. and Berberis vulgaris L. are common in all of their distribution .

Phenology —Flowering is in late April to early May, fruits and seeds maturie in late August to September.

Key to the varieties of R. cathartica (in N & W Iran)

1. Leaves glabrous, ovate to obovate and orbicular; shrubland in forest habitat ............................................................. var. cathartica

- Leaves pubescent, orbicular, ovate to elliptic or lanceolate; along rivers in forests, rocks and pasture; rocky forest habitat ............. ....................................................................................................................................................................................... var. caucasica