A short Milkweed, often found in colonies of many plants. Flowers are white, with 5 petals arranged in umbels. I measured flowers at 8 mm diameter. Leaves are opposite, lanceolate to ovate, typically 6 cm long and 2 cm wide. Stems and leaves have small hairs.
Habitat is prairie and the edges of aspen woodlands in south east Saskatchewan.
Height is listed in the reference books to 50 cm. Tallest plant in above photos was 25 cm.
Took the above photos on June 19th, at the Buffalo Grass Eco Reserve, 200 km south east of our home in Regina, SK.