Flower:

Slender-stalked flowers along branching stems and at branch tips, usually 1 flower per node, sometimes 2, second flower often not fully developed; a leaf-like bract is at the base of each stalk. Flowers are up to about ½ inch (7 to 17 mm) across with 5 pink to light purple, finely hairy rounded lobes, fused into a short tube white with pinkish purple spots on the inside. The upper 2 lobes are slightly smaller than the lower 3; all 5 lobes tend to be spreading. The calyx cupping the flower has 5 short triangular teeth. Flower stalks are hairless, 1/3 to 1¼+ inch (8 to 35 mm) long; bracts are hairless, linear and shorter than the stalk. Each flower only lasts a day before falling off and only a few flowers per branch bloom at a time.

Leaves and stems:

Leaves are opposite, linear to thread-like, ½ to 1+ inch (13 to 30 mm) long, less than 1/16 inch (to 1.4 mm) wide, toothless, hairless, stalkless, with a prominent central vein; smaller leaves in the axils (fascicles) may be present but are usually absent. Stems are much branched, smooth, weakly angled to nearly round in cross-section.

Fruit:

Fruit is a round to oval capsule less than ¼ inch (3.5 to 5 mm) long, containing yellowish-brown seeds.

Notes:

Rare throughout much of its range, Round-stemmed False Foxglove has been recorded only 5 times in Minnesota, the majority of those records well over a century old. According to the DNR, it was listed as a Threatened species in 1984 and upgraded to Endangered in 1996. In Minnesota it's been found in sunny, south-facing hill prairies in rocky or sandy soils along the Mississippi and St. Croix river valleys.

It is most easily confused with Slender-leaved False Foxglove (Agalinis teniufolia), a much more common species, which has similarly long flower stalks but are 2 at each node, the subtending bract may be longer or shorter than the stalk, and it's found in the wetter habitats of shores and wet meadows. Rough False Foxglove (Agalinis aspera), also a more common species, may be in the same habitat as A. gattingeri but is distinguished by its broader, rough-textured leaves, larger flowers and fruits 2 at each node, shorter flower stalks that are consistently shorter than the subtending bracts.