Buphthalmum is a small genus of perennial flowering herbs in the family Asteraceae (the daisy or aster family), placed within the order Asterales. The genus name is derived from Greek and alludes to the resemblance of the flower heads to an ox eye — a reference shared with several other yellow-flowered composites. Plants in the genus produce alternately arranged leaves along upright stems, each stem terminating in a solitary flower head. The heads are distinctive for their very narrow, strap-like phyllaries (bracts surrounding the head), surrounding bright yellow ray florets and yellow disc florets at the centre. The fruit is a cypsela — the typical achene-like fruit of the daisy family — usually crowned with a pappus of scales that aids wind dispersal; fruits from the ray florets may lack pappi altogether.
The genus is native to Europe, with species centred in the western Mediterranean and central European regions. Buphthalmum salicifolium (willow-leaved ox-eye) is the most widespread and the only species commonly cultivated as an ornamental; it has naturalised in parts of China and southeast Asia following introduction. GBIF recognises one accepted species in the genus, reflecting a narrow modern circumscription after several formerly included species were transferred to Telekia and related genera.
Etymology
The name Buphthalmum derives from the Greek bous (ox) and ophthalmos (eye), referring to the large, round, ox-eye appearance of the yellow flower heads. This folk-etymological naming parallels the common English name "ox-eye" applied to the genus and its best-known species.
Distribution
The genus is native to Europe, with its centre of diversity in western, central, and southern Europe. Buphthalmum salicifolium has the widest natural range and has been introduced beyond Europe, establishing in China and parts of southeast Asia.
Cultivation
Buphthalmum salicifolium is the only species in regular cultivation. It is grown as a hardy perennial border plant valued for its long season of bright yellow, daisy-like flower heads. It tolerates a range of well-drained soils and performs well in sunny positions. The species is sufficiently vigorous that introduced populations have naturalised outside its native European range.
