| canada | british columbia | juncus castaneus | species | 1 | 0 |
| canada | northwest territories | juncus castaneus subsp. leucochlamys | subspecies | 2 | 0 |
| canada | nunavut | juncus castaneus subsp. leucochlamys | subspecies | 5 | 0 |
| canada | yukon | juncus castaneus subsp. leucochlamys | subspecies | 1 | 0 |
| greenland | | juncus castaneus subsp. leucochlamys | subspecies | 6 | 0 |
| norway | | juncus castaneus | species | 3 | 0 |
| united kingdom | | juncus castaneus | species | 9 | 0 |