Flower:

Mostly single flowers, occasionally more, at branch tips with few if any flowers on the main stem. Flowers are tubular, ½ to ¾ inch long, pink to purple with 5 round, spreading lobes fringed with short hairs around the edge. The upper 2 lobes are slightly smaller than the lower 3. The tube throat is pale pink to white with reddish spots; 4 white-tipped stamens extend out of the tube. The lower lobes and throat are covered in short hairs.

The calyx has 5 broadly triangular lobes that are much shorter than the calyx tube, on a slender, spreading to ascending stalk that is up to 1 inch long.

Leaves and stems:

Leaves are linear to nearly thread-like, stalkless, ½ to 1½ inches long, hairless to slightly rough textured, mostly spreading, and typically bright green to yellowish green. Attachment is opposite but may be alternate on branches. Stems are smooth, weakly angled to nearly round, with many slender branches.

Fruit:

Fruit is a round capsule about 1/6 inch in diameter, containing many tan to yellowish 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. The related Rough False Foxglove (Agalinis aspera), a more common species, may be in the same habitat but is distinguished by its rough-textured leaves and larger flowers in the leaf axils of both the main stem and branches.