Centaurea scoparia Sieber ex Spreng.
Subshrub up to 40(60) cm in height, intricately branched, from white-pubescent to subglabrous, with the lower part and base of the branches woody and branches greyish or greenish with a single capitulum. Leaves linear, upper leaves entire, lower leaves with some clearly marked teeth, subacute, unarmed, laxly covering the branches up to almost the base of the capitula. Capitula with arachnoid indumentum, receptacle with setaceous scales. Involucre 13-15 mm, ovoid, with several rows of bracts, imbricate, coriaceous, with a yellowish-brown apical spine up to 15 mm, divaricated, usually with a pair of small spinules at the base. Flowers all in disc florets, white or yellowish, with longly exserted androecium, yellow-golden. Achenes c. 3.5 mm, oblongish, with pappus of ± the same length, formed by several rows of scabrid setae.
Flowering:
March to April.
Fruiting:
April to June.
Habitat:
Rocky outcrops and sandy soils of desert areas.
Distribution:
Its distribution area is restricted to the desert areas of the E of Egypt, including the Sinai Peninsula, Israel, Palestine, Jordan and Saudi Arabia.
Observations:
Another species with woody stems, at least at the base, is C. debdouensis Breitw. & Podlech, endemic to the arid areas of the Debdou region (NE Morocco); it is a small shrub up to 40 cm in height, that differs from C. scoparia by its pinnatisect leaves with linear divisions, and especially by its capitula, smaller and involucral bracts with an apical appendage with 3-6 cilia on each side and a much shorter spine, 1.5-3 mm long.
Conservation status:
Rare species, especially C. debdouensis, which has a very small distribution area. Currently, they have not been assessed at a global level in the IUCN Red List of Threatened Species.