Aquatic and Wetland Vascular Plants of the Northern Great Plains
41. Lamiaceae, the Mint Family
3. Physostegia Benth. -- Obedient plant
2. Physostegia parviflora Nutt. ex A. Gray
Stems 2-8 dm tall, from a slender caudex or short rhizome. Leaves
lanceolate to oblong-lanceolate, rarely ovate, 4-12 cm long, 0.7-2 cm wide,
acute to obtuse at the tip, remotely serrate or dentate to subentire, rounded
to subcordate and clasping at the base. Racemes 5-10 cm long; bracts
ovate to lanceolate or elliptic-lanceolate, to about 1/2 as long as the calyx.
Calyx 3-5(6) mm long in flower, to 7 mm long in fruit, sparsely stipitate
glandular, the teeth triangular, 1-1.5 mm long; corolla lavender to purple-lavender,
9-16 mm long, puberulent and usually with stipitate glands. Nutlets 2.1-3.3
mm long. Jul--Aug. Wet meadows, shores and stream banks; rare, with records
from nc ND and w NE; (sw Man., n ND, s Sask.; also w NE, WY and w MT to n OR,
WA and B.C.).