Big-head Star-thistle - Centaurea macrocephala
Bighead Knapweed, Big Yellow Centaurea, Armenian Basketflower, Yellow Hardhat, Yellow Bachelor's Button
Plants: Stems erect, little branched, 50-150 cm; herbage short-villous, thinly arachnoid.
Leaves: Basal and alternate, simple, petiolate below; the blades oblanceolate, 5-30 cm long, entire or dentate, the upper ones wavy-margined, clasping to decurrent.
Inflorescence: Heads discoid, solitary. Involucres hemispheric, about 2-3 cm high; phyllaries well-imbricate in numerous series, the outer ones obovate, green to tan with a brown, scarious, highly fringed appendage wider than the bract; receptacle flat, bristly.(Adapted from Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX.)
Introduced ornamental sparingly escaped in northwest and northeast North America. Known from Gallatin and Pondera Counties in Montana (adapted from Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX.)
Observations in Montana Natural Heritage Program Database
Number of Observations:
(Click on the following maps and charts to see full sized version)
Map Help and Descriptions
(Observations spanning multiple months or years are excluded from time charts)
Flowers: Disk flowers perfect, numerous, yellow, the outer ones with a slightly expanded limb, the inner about 2 cm long; style branches short, united with a thickened ring at the base.
Fruit: Achenes ellipsoid, glabrate, 7-8 mm long. Pappus of many flattened bristles.(Adapted from Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX.)
- Literature Cited AboveLegend: View Online Publication
- Flora of North America Editorial Committee. 2006. Flora of North America North of Mexico. Vol. 19. Magnoliophyta: Asteridae, part 6: Asteraceae, part 1. Oxford Univ. Press, New York. xxiv + 579 pp.
- Lesica, P., M. T. Lavin, and P. F. Stickney. 2012. Manual of Montana Vascular Plants. Fort Worth, TX: BRIT Press. viii + 771 p.
- Additional ReferencesLegend: View Online Publication
Do you know of a citation we're missing?
- Lesica, P., B. Christiaens, D. Hanna, L. Larsen, and C. Odegard. 2013. Noteworthy collection. Madroño 60(3): 262-263.