White Prickly-poppy - Argemone polyanthemos
Argemone intermedia var. polyanthemos
(see State Rank Reason below)
MNPS Threat Rank
State Rank Reason (see State Rank above)
Native to the Great Plains though it is unclear whether it was native to Montana or has been introduced.
Taprooted annual or biennial. Stems 40–80 cm with prickly foliage. Leaves oblanceolate, to 10 cm long, glaucous, deeply pinnately lobed with spiny-toothed margins, the upper clasping. Inflorescence bracteate cymose. Flowers 5–10 cm across; sepals 3, prickly; petals 6, white; stamens numerous with yellow filaments. Capsules ellipsoid, ca. 2 cm high, yellow-spiny (Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX)