E-Flora BC: Electronic Atlas of the Flora of British Columbia

Silybum marianum (L.) Gaertn.
milk thistle (blessed milkthistle)
Asteraceae (Aster family)

Introduction to Vascular Plants

© Jamie Fenneman  Email the photographer   (Photo ID #10792)

E-Flora BC Static Map
Distribution of Silybum marianum
Click here to view our interactive map and legend
Details about map content are available here
Click on the map dots to view record details.

Species Information

Click on the image below to view an expanded illustration for this species.



General:
Annual or biennial herb from a fibrous root; stems erect, solitary, simple or few-branched, ridged, glabrous to sparsely woolly-hairy, 0.5-1.5 m tall.
Leaves:
Basal leaves lacking; stem leaves elliptic below, becoming oblanceolate or lanceolate above, alternate, spiny-toothed, pinnately lobed, 15-80 cm long, 5-30 cm wide, veins lighter in colour thus leaves appearing white-mottled, stalked below, becoming unstalked above with conspicuous ear-like flanges, clasping at the bases.
Flowers:
Heads discoid, terminating the branches; involucres 2-6 cm wide; involucral bracts narrowly egg-shaped, margins spiny, tips spiny but basally expanded; ray flowers lacking; disk flowers purple.
Fruits:
Achenes elliptic to egg-shaped, 6-7 mm long, flattened, dark brown with a narrow, yellow, apical collar, glabrous; pappus with numerous bristles, these deciduous in a ring.

Source: The Illustrated Flora of British Columbia

Habitat / Range

Mesic to dry roadsides and disturbed areas in the lowland zone; rare on SE Vancouver Island and the adjacent mainland; introduced from the Mediterranean region.

Source: The Illustrated Flora of British Columbia

Climate

The climate type for this species, as reported in the: "British Columbia plant species codes and selected attributes. Version 6 Database" (Meidinger et al. 2008), is not evaluated, unknown or variable.

Synonyms and Alternate Names

Carduus marianus L.
Mariana mariana (L.) Hill

Taxonomic and Nomenclatural Links

Additional Photo Sources

General References