Cowcockle

Vaccaria pyramidata

Plants glabrous, glaucous. 
Stems 20-100 cm. 
Leaf blades 2-10 cm, base cuneate to cordate. 
Cymes open, 16-50(-100)-flowered. 
Pedicels (5-)10-30(-55) mm. 
Flowers: calyx 9-17 mm, with 5 prominent, usually green, winged angles or ridges, each ridge with strong, cordlike marginal vein; petals with claw 8-14 mm, blade 3-8 mm. 
Capsules included in calyx tube.
Seeds 2-2.5 mm wide. 2n = 30.