Asparagus L.
Genus comprised of about 210 species, mainly in the in the Northern Hemisphere. 9 in North Africa, of which 3 are herbaceous (A. officinalis, A. maritima and A. aphyllus) and 3 more are woody (A. altissimus, A. albus and A. pastorianus). They are distributed unevenly almost throughout the entire Mediterranean area.
In the middle the other 3 species that grow in the region, with slightly woody stems, but hardly to be considered as shrubs or shrublets, they are:
A. horridus L. (A. stipularis Forssk.) Ara. (Egypt): Aqoul gabal, shawk, halioun), with cladodes fasciculate by 2 or 3, very large (up to 5 cm), persistent, linear, rigid and sharp; and A. acutifolius L., with cladodes fasciculate by 4-12, small (3-6 mm), persistent, linear, semirigid and slightly prickly. Both species are distributed throughout the Mediterranean area, except for the steppes and cooler and wetter areas. In Libya A. horridus grows throughout the northern Mediterranean strip, but A. acutifolius is very rare (cited only in the vicinity of Khoms).
A final species worthy of mention is A. verticillatus L., a perennial plant, with stems not too lignified, but reaching up to 2.5 m in length; erect or flexible branches; cladodes (20-60 × 0.5-1.2 mm), trigonous, and with papillae in the margins, grouped in whorls of (1)10-20(30); fruits 5.5 to 8 mm, black. Distributed in the eastern Mediterranean. In North Africa it is only found, and appears as adventitious, in NE Libya (Jebel Akhdar, reaching to the W to the Kuf River).
In principle none of these species are considered threatened. A. horridus are not currently assessed at a global level in the IUCN Red List of Threatened Species, while A. acutifolius and A. verticillatus are considered at a global level as Least Concern (LC) (Rhodes & Maxted, 2016).
Key to species
1 Stems herbaceous or slightly lignified at the base.Cladodes forming straight and large (up to 5 cm) spines Asparagus horridus
1 Stems well lignified, the oldest strongly woody.Cladodes slightly or not spinescent, small (up to 3 cm) 2
2 Climbing shrublet, lianescent, that can reach up to 6-8 m in height.Cladodes flexible Asparagus altissimus
2 Shrublets that can climb to some extent but not lianescent, up to 1.5 m in height. Cladodes rigid or semi 3
3 Shrublet very slender, not spiny, with somewhat woody stems. Cladodes short (3-6 mm) dark green, slightly spinescent Asparagus acutifolius
3 Bulkier shrublets, with stems and spines distinctly woody. Cladodes longer (10-30 mm) green-greyish, ± acute but not spinescent 4
4 Young branchlets white. Foliar spines nearly straight.Widely distributed in the Mediterranean region Asparagus albus
4 Young branchlets blackish. Foliar spines distinctly recurved backwards.Endemic to SW Morocco Asparagus pastorianus
Updated by: B. Valdés & J. Charco.