Perideridia gairdneri (Squawroot) - photos and description

Perideridia gairdneri

Perideridia gairdneri
15 cm ruler in above photo for scale

Perideridia gairdneri

Perideridia gairdneri

Perideridia gairdneri

Perideridia gairdneri
Lower stem leaf in above photo

Perideridia gairdneri
Second example of a lower stem leaf in above photo

General: Slender, erect perennial, with larger plants branching towards the top. Plants glabrous.

Flowers:  Compound umbels of small, white flowers. Compound umbels measured to 8.5 cm across, a single umbellet measured to 18 mm across. Flowers are fragrant, we measured them to 3 mm diameter.

Leaves: Leaves alternate, pinnate with 5-7 narrow leaflets, leaflets are entire. We measured leaflets to 3 mm wide.

Height: Height listed in Budd's Flora to 80 cm, we measured plants to 70 cm tall.

Habitat:  Meadows, woodlands, and ravines in the Cypress Hills.

Abundance: This plant is very rare, ranked as an S2 by the Saskatchewan Conservation Data Centre. 

Origin: Native.

How to identify this plant: There is only one species of Perideridia that grows in Saskatchewan. Genus Perideridia is identified in family Umbelliferae in Budd's Flora by its leaves: "Leaf segments few, usually 5, long and linear." This taxonomic key works pretty well to identify the plant, as long as you realize there are linear bracts subtending the flower umbels, and not linear, simple stem leaves subtending the umbels.

When and where photographed: The above photos were taken August 10th grassy ravine slopes, Cypress Hills, about 450 km southwest of our home in Regina, SK.