SILYBUM MARIANUM

Family and Genus:- See- COMPOSITAE

Common Names:- Milk Thistle.

Homotypic synonyms:- Carduus marianus; Mariana mariana.

Meaning:- Silybum. From Greek silybon, an ancient name for a thistle-like plant.
Marianum. Latin, “of Mary”, associated with the traditional legend explaining the white marbling of the leaves.

General description:- A robust annual or biennial thistle with glossy white-marbled leaves and large purple capitula. A neophyte in Great Britain.

Stems:-
1) Usually 50-150 cm high, erect, stout, branched and leafy.

Leaves:-
1) Lower, large, oblong to oblanceolate, pinnatifid, glossy green with conspicuous
white marbling along the veins and strongly spiny margins.
2) Upper, alternate, sessile, clasping, similarly white-marbled and spiny.

Flowers:-
1) Capitula, large, solitary, terminal and purple.
2) Phyllaries, imbricate, the outer and middle ending in long stout spreading spines.
3) Florets, all tubular, bisexual and fertile, purple, with 5 lobes.
4) Stamens, 5, with anthers united into a tube around the style.
5) Ovary, inferior, unilocular, with a single ovule.

Fruit:-
1) Cypsela, obovoid, smooth, glossy, dark brown to blackish and often mottled.
2) Pappus, of numerous white bristles united at the base and deciduous as a ring.

Distinguishing features:-
Readily distinguished by the conspicuous white marbling of its glossy leaves, very strong marginal spines and large solitary purple capitula with long spine-tipped phyllaries.

Flowering time:- June to August.

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Toxicity:- The plant is very spiny and can cause mechanical injury. Preparations from the fruits are used medicinally, but self-treatment or ingestion of wild material is not recommended.

Habitat:- Waste ground, roadsides, field margins, coastal disturbed ground, farmyards and other nutrient-rich open places.

Distribution:- Neophyte in Great Britain and Ireland, locally naturalised. Native from Macaronesia and the Mediterranean region eastwards to Central Asia and India.

Conservation status:- No native Great Britain Red List category.

Photos by:- Steve Lenton