RUBIACEAE Juss.
A large family with about 609 genera and about 13,673 species, with a tropical and subtropical distribution. These are trees, shrubs and herbaceous plants with simple leaves, inflorescences generally cymose and flowers usually hermaphrodite, actinomorphic. Corollas infundibuliform or generally rotate with 4-5 lobes. Ovary inferior, bilocular and fruit in capsule, berry or drupe.
An economically important family, including plants such as coffee or quinine. In North Africa most of its species are herbaceous, often thermophytes in poor, ruderal or weedy soils. The only genus with woody representatives of good size is Rubia, mainly lianas with more or less woody stock.
The other genus of this family that has woody species in North Africa is Plocama Aiton, with 4 species, all of them small chamaephytes, 10-50(80) cm in height, with opposite leaves, tetramerous flowers and fruit in drupe with 2 mericarps.
The largest species is P. reboudiana (Coss. & Durieu) M.Backlund & Thulin [Gaillonia reboudiana Coss. & Durieu, Jaubertia reboudiana (Coss. & Durieu) Ehrend. & Schönb.-Tem.] (Ara.: Sedrat, Cheikh), characterised by its linear leaves, from subcylindrical to cylindrical, fleshy; flowers (in pairs) surrounded by a dense involucre formed by linear bracts, sparse but covered in long white cilia. It grows in the driest areas of the southern Mediterranean region and the northern Sahara, in Morocco, Algeria and Tunisia.
The other 3 species do not have that showy involucre. More broadly distributed, since it reaches Libya, is P. calabrica (L.f.) M.Backlund & Thulin [Asperula calabrica L.f., Putoria calabrica (L.f.) DC., Putoria hispanica Boiss. & Reut.], with obovate to elliptical leaves, not too fleshy, and flowers grouped in cymes of 6-15. P. brevifolia (Coss. & Dur. ex Pomel) M.Backlund & Thulin (Putoria brevifolia Coss. & Dur. ex Pomel) in endemic to Morocco; it is characterised by its small leaves, broadly lanceolate, fleshy, and its solitary flowers. Finally, P. calycoptera (Decne.) M.Backlund & Thulin [Spermacoce calycoptera Decne., Pterogaillonia calycoptera (Decne.) Lincz.], from the Middle East, from Egypt to Pakistan; in North Africa it only grows in Egypt. It can be distinguished by its linear leaves, somewhat fleshy, and flowers generally solitary.
Fairly common and widely distributed species. Currently, they have not been assessed at a global level in the IUCN Red List of Threatened Species.
Updated by: H. Sainz & J. Charco.