Buddleja misionum is a species endemic to dry rocky fields and roadsides in southern Paraguay, the Rio Grande do Sul in Brazil, and the provinces of Corrientes and Misiones in Argentina; it was first described and named by Kraenzlin in 1913. 
B. misionum is a dioecious shrub 1 – 2 m high, with tan fissured bark. The branches are subquadrangular and covered with a dense tomentum. The sessile lanceolate to elliptic leaves are 5.5 – 10 cm long by 1.4 – 4 cm wide, lanose above and below. The yellow inflorescences are 15 – 30 cm long, comprising 5 – 15 pairs of heads 1 – 1.5 cm in diameter located in the axils of the terminal leaves, each head with > 20 flowers; the corolla tubes 4.5 – 5 mm long.
The shrub is not known to be in cultivation.
- Kraenzlin, F. W. L. (1916). repert. Spec. Nov. Regni. Veg. 14: 294 – 295. 1916
- Norman, E. M. (2000). Buddlejaceae. Flora Neotropica 81. New York Botanical Garden, USA