Artemisia L.
Genus composed of about 480 species, widely dispersed throughout the northern Hemisphere. In North Africa it is represented by some 22 species, distributed mainly through the Mediterranean area. In general, they are chamephytes smaller than 50 cm, although sometimes species such as A. judaica and A. absinthium can reach up to 1 m in height. Only one species, A. arborescens, can be considered truly shrubby. Among the other species, the following stand out as the most robust:
A. campestris and A. herba-alba are Mediterranean, missing almost entirely from the northern Sahara but with isolated populations in the mountainous massifs of the central Sahara as vestiges of the past, when these mountains were covered by Mediterranean vegetation.
Although small in size, usually smaller than 50 cm, there are 3 species that can become very common. The 3 with more or less whitish young twigs because they are covered with white hairs. They are:
A. herba-alba Asso (Fre.: Armoise blanche, Tamahaq: Zazaré). One of the most common species. It is very polymorphic and numerous subspecies have been described that have often been elevated to the rank of species. It differs by its very small adult leaves (2-8 mm long), greenish-greyish, with very narrow, filiform segments (less than 1 mm wide); elongated, narrow capitula (1-3 mm wide), with few flowers (3-6); it grows in dry areas in the southern Mediterranean region.
A. barrelieri Besser, which is up to 0.7 m in height and characterised by its adult leaves (1-2.5 cm), bipinnate, with terminal linear-spatulate segments, less than 1 mm wide, and ovoid floral capitula, 2.5-3 mm in diameter, homogamous (with all flowers hermaphrodite); it is endemic to the SE Iberian Peninsula and the N of Morocco.
A. alba Turra (A. fruticosa Asso), with woody stems at the base, glabrescent and greenish leaves, with segments 1-2 mm wide and capitula (3-4 mm wide) in narrow spiciform inflorescences. It is a Mediterranean plant that has 2 subspecies in North Africa: subsp. chitachensis Maire, endemic to Morocco, and subsp. kabylica (Chabert) Greuter, endemic to Algeria (western Kabylia: Aïn El Hammam).
Some species and more specifically, A. herba-alba, play a very important role in the formation of vast North African landscapes, mainly in steppic zones, where these chamaephytes are often dominant.
Common and widely distributed species. Currently, they has not been assessed at a global level in the IUCN Red List of Threatened Species.
Ling. Y.R. 1991. The Old World Artemisia L. (Compositae). Bull. Bot. Res. Harbin 12(1): 1-108.
Filatova, N. 1986. Species Artemisiarum (Asteraceae) subgeneris Seriphidium (Besser) Peterm. florae Africae septentrionalis. Nov. Syst. Vyssh. Rast. 22: 214-224.
Ouyahia, A. 1987. Systematique du genre Artemisia L. au Maroc. Thèse doc. ès-sciences. Univ. Aix-Marseille III. 433 pág.
Ouyahia, A. 1990. Clé de détermination des espèces marocaines du genre Artemisia L. Al Biruniya 6(1): 31-91. Rabat.
Ouyahya, A. 1995. Systématique du genre Artemisia au Maroc. in D.J.N. Hind & al. (eds.) in Advances in Compositae Systematics 293-354. Roy. Bot. Gard. Kew.
Key to species
1 Capitula ovoid, oblongish or campanulate, 1.5-3 mm in diameter, with 2-12 flowers 2
1 Capitula hemispheric, 3-6 mm in diameter, with more than 20 flowers 5
2 Plant glabrescent, green or slightly glaucous. Capitula heterogamous, with peripheral female flowers, the rest all disc florets and hermaphrodite 3
2 Plant grey or white tomentose, at least in young parts, not viscous. Capitula homogamous, with all the flowers in disc florets and hermaphrodite 4
3 Leaves green-glaucous, slightly fleshy, not viscous Artemisia monosperma
3 Leaves green, not fleshy, viscous when young Artemisia campestris
4 Branches ± erect. Capitula ovoid or campanulate. Leaves halfway along the stem 15-20(22) mm, petiolate, with lobes (0.2)0.3-0.6 mm wide Artemisia barrelieri
4 Branches ± patent. Capitula oblongish. Leaves halfway along the stem up to 10(15) mm, sessile, with lobes 0.2-0.3 mm wide Artemisia herba-alba
5 Receptacle glabrous 6
5 Receptacle hairy 7
6 Plant glabrous or white-tomentose. Lower leaves 2-3 pinnatisect, with linear lobes longer than wide. Capitula with lanceolate outer bracts Artemisia alba pp
6 Plant densely grey or whitish-tomentose. Lower leaves 1-2 pinnatifid or pinnatipartite, with ovate or oblong lobes, barely longer than wide. Capitula with suborbicular outer bracts Artemisia judaica
7 Lower leaves 2-3 pinnatisect, with lobes less than 1 mm wide. Capitula with 20-40 flowers and lanceolate outer bracts Artemisia alba pp
7 Lower leaves 1-3 pinnatisect, with lobes 1-4(6) mm wide. Capitula with 40-120 flowers and ovate or oblong outer bracts 8
8 Leaves 2-3 pinnatisect, punctate-glandular, with oblong-lanceolate lobes 1-4 (6) mm wide. Capitula 3-4 mm wide, with oblong outer bracts Artemisia absinthium
8 Leaves 1-2 pinnatisect, not punctate-glandular, with linear lobes 1-2 mm wide. Capitula 6-7 mm in diameter, with ovate outer bracts Artemisia arborescens
Updated by: B. Valdés & J. Charco.