Onopordum nervosum, commonly known as Moor's cotton thistle or reticulate thistle, is a species of flowering plant in the genus Onopordum within the family Asteraceae. It was first described by the Swiss botanist Pierre Edmond Boissier in 1841, based on his botanical travels in southern Spain.
Distribution and habitat: The species is native to the Iberian Peninsula (Spain and Portugal). It has been introduced elsewhere, including Britain, where it is considered a neophyte (a non-native plant that has become established). In Britain, it occurs on waste ground and in rough places, often arising as a garden escape, and can become naturalized.
Description: It is a large, biennial herb. The plant produces spiny, thistle-like flower heads typical of the genus.
Taxonomy: Two subspecies are currently accepted:
- Onopordum nervosum subsp. castellanum Gonz.Sierra, Pérez Morales, Penas & Rivas Mart.
- Onopordum nervosum subsp. nervosum
Several natural hybrids with other Onopordum species have been documented, including hybrids with O. corymbosum, O. hinojense, O. illyricum, and O. macracanthum.
Common names: In addition to Moor's cotton thistle and reticulate thistle (English), it is known in Spanish as cardo blanco portugués, cardo borriguero, cardo gigante, espina blanca portuguesa, and toba gigante; in Portuguese as onopordo-dos-árabes; and in Catalan as bufassa aràbiga and cardot nervós.
Cultivation: The plant has gained the Royal Horticultural Society's Award of Garden Merit, indicating it is a recommended ornamental garden plant.
Conservation status: The species has not been evaluated by the IUCN Red List.
