southern obedient plant

not listed

NNR - Unranked

SNR - Unranked

not listed

FACW - Facultative wetland

FACW - Facultative wetland

FACW - Facultative wetland

Southern obedient plant is a 2′ to 5′ tall, erect, perennial forb that rises on multiple stems clustered on a short caudex.

The stems are erect, hairless, 4-angled, and hollow. They have 10 to 34 opposite pairs of leaves and are often branched near the top with several racemes.

The leaves are opposite, hairless, lance-shaped or inversely egg-shaped, up to 5″ long and 1½″ wide. The bottom 1 to 7 pairs may be stalked and soon fall off. The remaining leaves are stalkless. The margins are toothed usually with sharp teeth, sometimes with blunt teeth, or are rarely untoothed.

The inflorescence is a elongated, unbranched cluster (raceme) at the ends of the stems and branches. The racemes are 2″ to 6″ long when in flower and have 4 rows of densely packed flowers that mature from the bottom up. There are usually some empty floral bracts below the inflorescence. When moved left or right the individual flowers stay where they are moved, hence the name “obedient plant”.

The flowers are ⅔″ to 1⅓″ long. The 5 sepals are green, ¼″ long, and are fused at the base into a tube with 5 sharply pointed lobes. The 5 petals are pink with purple spots on the inside. They are fused at the base into a tube with 2 lips. The upper lip is broad, hood-like, and overhanging. The lower lip is divided into a broad central lobe and 2 smaller lateral lobes. There are 4 stamens with purple anthers visible under the upper lip. There is no floral scent.

The fruit is a smooth nutlet with 1 seed.

2′ to 5′

Pink

Obedient plant (Physostegia virginiana ssp. virginiana) stems are scattered along a long, horizontal rhizome. There are no empty floral bracts below the inflorescence.

Dry to moderate moisture. Prairies, open woods. Full to partial sun.

August to October

Sources

3, 4, 29, 30.

Native (?)

USDA PLANTS shows this species as native to Minnesota. However, no records can be found.

Physostegia virginiana is a highly variable species. Many varieties and subspecies have been described. An analysis of several varieties and subspecies (Cantino, 1982) concluded that only two subspecies should be recognized, and they roughly equate to the northern and the southern groups. The northern subspecies P. v. ssp. virginiana is the only subspecies that occurs in Minnesota. USDA PLANTS shows the southern subspecies P. v. ssp. praemorsa also native to Minnesota, however no records of that subspecies in the state can be found.