Family
Asteraceae
Distribution in Canada
Present in ON
Duration of life cycle
Annual
Seed/Fruit type
Achene - a one-seeded, dry fruit
Seed identification features
Size
- length: 4.0–6.0 mm
- width: 2.5–3.5 mm
- thickness: 1.0–1.5 mm
- spine length: 3.0– 4.0 mm
Shape
- in outline: triangular
- in cross section: rectangular
Surface texture
- smooth and glossy
- covered in 1.0 mm-long hooked spines
Colour
- light brown to medium brown
- spines tend to be darker
Other structures
- two long, spreading spines (may be slightly curved) at top, or apex, of seed
Similar species
Low starbur (Acanthospermum humile)
- found in southeastern United States and New York state
- similar to hisbid starbur in triangular shape, medium-brown colour, and the presence of 2 long spines coming from apex
- shorter and narrower than hisbid starbur by 0.5–1.0 mm
- hooked spines run along only one side of achene (hooked spines cover the hispid starbur achene)
- slightly curved to one side (hispid starbur achene is straight)
Photos
Similar species
