05/29/2026
Today’s Flora Friday highlights Lomatium ambiguum or swale desert-parsley. In BC, this species is ranked S5, or secure. It seems to require open habitats and otherwise is not very picky, as it can be found on a variety of habitats including rocky slopes, shrubland gaps, and dry meadows. It can occur over bedrock in moss, and in a variety of moisture conditions, from dry sites to quite wet seepages with spring snowmelt runoff, though it likely requires dry summer conditions. It ranges from Utah northwest to southern BC and does not reach AB.
Lomatium is a genus in the Apiaceae or carrot family and has many small flowers grouped into umbels. In western Canada, there are at least twelve yellow-flowered Lomatium species, though generally only 3 to 4 are present in a given area, and they mostly differ in leaf structure and other assessed at a glance characters, with the exception of south central and eastern BC where L. ambiguum, L. triternatum, and L. simplex all occur and look very similar. All are members of the L. triternatum complex, which is the subject of a paper with a rare pun in the title: “Try Tri again? Resolving species boundaries in the Lomatium triternatum (Apiaceae) complex”. L. ambiguum and L. triternatum often look extremely similar and some individuals can appear intermediate. Both have leaves divided several times into skinny lobes that end in groups of three. L. triternatum has longer lobes that are often pointy, while those of L. ambiguum should be shorter and appear more rounded. L. ambiguum fruits should also have narrower wings, though these are very difficult to locate since they mature after the rest of the plant has withered.
Some Lomatium species have underground tubers and are a traditional food for First Nations, though L. ambiguum does not produce a particularly notable tuber, it would be more worth it to collect seeds, grow them, and experiment with the new seeds as a dill/cumin style spice. Flowering early in spring, it supports many spring bees, some of them quite uncommon mining bees that likely specialize in part on Lomatium pollen.
Photos and writeup by Rowan Rampton.
-parsley