Rumex abyssinicus Jacq.

Global description

Rumex abyssinicus is a robust vivacious, erect plant, reaching up to 4 m in height. The stem is green or reddish green, furrowed, glabrous, usually unbranched. The leaves are alternate, simple, entire, glabrous, long-stalked. At the base of the petiole is a brown cylindrical membranous sheath surrounding the stem. The leaf blade is long triangular or spearhead shaped. Green flowers are made of small circular leafy pieces, 4 to 5 mm in diameter, arranged on large loose and highly branched non-leafy inflorescences, rapidly becoming brown to reddish brown. The fruit is dry, triangular section.
 
First leaves

First leaves simple, petiolate, in rosette. The lamina is triangular to hastate in shape.
 
General habit

Plant in rosette the first year, then becoming a robust plant, sparsely branched, generally 1 to 2 m in height but can reach 4 m high.
 
Underground system

Taproot thick, yellow and very deep.
 
Stem

Cylindrical stem, furrowed, smooth, fleshy, green or reddish green, can reach up to 3 cm in diameter.
 
Leaf

Leaves simple, alternate, long-stalked (up to 14 cm long, often longer than the blade). At the base of the petiole is an ocrea, cylindrical membranous sheath surrounding the stem, 10 to 18 mm long, brown in color. The basal leaves have a triangular blade, hastate or saggitate, sometimes sublinear or rarely oval, 5 to 30 cm long and 4 to 20 cm wide, basal lobes spreading, more rarely directed forwards, acute or obtuse at the top. The base is truncated, rounded or cordate, the apex is in acute. Both sides are glabrous; venation is palmate. The margin is entire. The upper leaves are progressively smaller, becoming subsessile.
 
Inflorescence
 
Inflorescence in large terminal panicle, branched, non foliage, oblong or pyramid, reaching up to 40 cm long and 25 cm wide, formed of dense whorls.
 
Flower
 
The hermaphrodite flowers are carried by a pedicel, reaching up to 5 mm long. The flowers are surrounded by 2 sets of 3 tepals, first green then becoming quickly brown. External tepals are small and thin, spread out or reflected on the fruit. The inner tepals are circular, cordate, accrescent, pellucid, with reticulate venation. They are green turning to brown or reddish brown, entire, from 4 to 5 mm diameter on the fruit, with deep basal sinus up to 1 mm, having small reflected protuberances. They do not have tines at the time of fruiting.
 
Fruit
 
The fruit is a trigonal achene, 2 to 3 mm in diameter, light brown, shiny.

Origin

Rumex abyssinicus is native to Central and Eastern Africa and Madagascar.

Worldwide distribution

This species has been introduced in Europe and in the Indian Ocean in Réunion.

https://www.gbif.org/fr/species/4035195