Common name(s): bachelor's button; cornflower
- Wikipedia. Online encyclopedia entry (if defined).
- Google images. Web search for photographs.
- GRIN. Taxonomical details, with common names, distribution, and synonyms.
- The Plant List. Taxonomical lookup
Links for Centaurea cyanus
- All Things Plants - Community-assembled plant profile (14 varieties in database) (20 photos)
- Annie's Annuals: Centaurea cyanus 'Black Gem' - Catalog page with photo, basic horticultural information, and noteworthy features. (additional cultivars listed in catalog) (2 photos)
- BBC Gardening - Plant profile with horticultural details and garden uses. (1 photo). Also a page for 'Black Ball'.
- Dave's Garden PlantFiles - Profile page with horticultural basics, and member-contributed photos and comments. (54 photos)
- Denver Botanic Gardens - Description, native range, and cultural requirements. (additional pages for other varieties) (8 photos)
- Iris' Garden - Gardener in the Netherlands presents a photo of this plant, with basic horticultural information. (1 photo)
- Kansas Wildflowers & Grasses - Plant portrait with botanical details and description (4 photos)
- Missouri Botanical Garden - Plantfinder page for one of the plants growing at the garden, with usually one or more photos, horticultural information, and noteworthy characteristics. (4 photos)
- Missouri Plants - Description and photographs of botanical features, with notes about habitat and native status. (5 photos)
- North Carolina State University factsheet - Plant profile with horticultural details and comments (1 photo)
- Ontario Rock Garden Society - Germination information
- Paghat's Garden - Illustrated articles by a gardener in the Pacific Northwest, with background and personal observations. (6 photos)
- Rob's Plants - Plant profile with basic horticultural information and often personal observations. (1 photo)
- Turner Photographics - Profile of wildflower of the US Pacific Northwest, with botanical description, habitat and distribution, and photo gallery.