Cheirolophus mauritanicus (Font Quer) Susanna
Centaurea sempervirens var. mauritanica (Font Quer) Jahand. & Maire
Shrub up to 1.5 m in height with an indumentum formed by abundant glandular pluricellular hairs and scarce eglandular hairs, with woody branches in the lower half and abundantly branched in the upper half. Leaves of the middle part of the stem lanceolate, serrated, sessile, amplexicaul, with 2 stipuliform lobes at the base; upper leaves linear, entire and without lobes at the base; uppermost leaves subinvolucrate. Capitula with hairy receptacle and involucre 15-25 mm in diameter, with several rows of imbricate, scarious and glabrous bracts; outer and middle bracts ovate-elliptical, with 3-5 clear veins on the outside and a yellowish appendage from semilunate to widely triangular, with 10-16 cilia longer than the body of the appendage, flexuous, scabrid. Flowers all in disc florets, purple; outer florets sterile or feminine; inner florets hermaphrodite. Achenes 5-6 mm, oblongish, glabrous, with lateral-basal hilum partly hidden by 3 lobes of the pericarp; pappus c. 3 mm, formed by a row of white and scabrid setae; hilum of outer achenes promptly caducous.
Flowering:
April to June.
Fruiting:
May to July.
Habitat:
Cool and shady areas of low and medium altitude mountains.
Distribution:
It is a rare endemic species of the Tellian Atlas in Algeria (Chiffa, Mouzaïa) and the Rif of Morocco [Tetuan (Semsa), Xaüen (Jebel Kalaa, Ras-el Ma, Jebel Tissuka)].
Observations:
The other 2 species of this genus are endemic to the Atlas Mountains of Morocco. They differ from C. mauritanicus because their leaves do not have stipuliform lobes, as well as for their smaller capitula with arachnoid indumentum, not glabrous; In addition, the involucral bracts have a more elongated appendage, with shorter and somewhat stiffer cilia, particularly in Ch. benoistii.
Ch. benoistii (Humbert) Holub is a subshrub, highly branched, up to 1 m in height; branches with laxly arranged leaves, each with a single capitula; lower and middle leaves are ± laxly white-tomentose on both sides, petiolate and subentire or dentate; capitula with pink flowers, with involucre slightly arachnoid, 10-15 mm in length and bracts with not decurrent appendage and with 7-11 short setae. It is endemic to the Anti-Atlas (Tizi-n-Ounzour), High Atlas and Middle Atlas.
Ch. tananicus (Maire) Holub is a somewhat smaller subshrub that does not reach 1 m in height. Leaves green on both sides; lower and middle leaves can be dentate or lobed, with lobes ovate or triangular and mucronate. Capitula of purple flowers, with an involucre c. 15 mm, slightly arachnoid, bracts with a ± longly decurrent appendage, with 1 rigid terminal seta and 4 flexuous setae on each side. It is only known from 3 locations in the High Atlas (Ida-ou-Tanane, Sksaoua and Tizi-n-Test).
Conservation status:
Rare species with very small distribution areas. Currently, they have not been assessed at a global level in the IUCN Red List of Threatened Species.