Large-flowered Golden Thistle

Scolymus grandiflorus is a spiny herbaceous annual or biennial of up to ¾ m high, that contains a milky latex. It has twenty chromosomes (2n=20).

Root, stem and leaves. The stems carry uninterrupted spiny wings along their lengths. The rosette leaves are usually 10-16, exceptionally up to 24 cm long and ovate to oblong in shape, pinnately incised, with a wavy, spiny and dentate margin. The leaves on the stem are alternately set and are smaller but comparable to the rosette leaves.

Inflorescence, flowers and fruits. The flowerheads are seated at the end of the stem or in the limbs of the higher leaves, and are arranged in a spike, which are subtended by two or three leaflike bracts. Each flowerhead is circled by an involucre that consists of many spine-tipped bracts of usually between 9 and 15 mm long, in several rows, the outer papery and shorter than the inner ones, which are leaflike in consistency and have a white papery margin. These surround the common floral base (or receptacle), which is mostly 13–18 mm in diameter conical in shape and is set with ovate papery bracts called chaff or paleae. Inplanted are dorsally compressed cypselas, each enclosed by a palea, the outer rows higher than the inner ones. There are three to seven pappus bristles on top of the cypselas in the centre, three to five with bordering the involucre. …

The species is most widely present in Morocco, Algeria, Tunisia, Malta, Libya, and on Sicily. It further occurs in Lebanon, Turkey, Italy (Sicily, Sardinia, Lombardia, Tuscany, Basilicata, Calabria, Puglia and Abruzzo), and in France (the coast of the Languedoc-Roussillon region, the departement Bouches-du-Rhône and on southern Corsica), but has a patchy distribution in these parts. Remarkable is its absence from the east of Spain and the Balears and from the south of the Balkans.

S. grandiflorus has a preference for coastal areas, and can mostly be found on sandy soils. It grows on wastelands, often in the company of Carduus spp., Carthamus spp. and Onopordum spp.