Silvery phacelia – State Wildlife Action Plan

Photo Credit: Oregon Department of Agriculture

Silvery phacelia is a perennial arising from an often much branched and elongated caudex. Stems are stout, decumbent to ascending, and 10-45 cm long, the stems and petioles white hispid to hispidulous with fine, upward-appressed hairs. Leaves are thick, entire or with a pair of leaflets below the main blade, 5-12 cm long by 2-3 cm wide, elliptic to orbicular or obovate, and densely covered with silky long hairs, the vein pattern outlined by furrows on the upper surface. Robust plants often have lower leaves with well-developed axillary rosettes and occasionally with elongated floral branches bearing multiple cymes. Floral branches are often clustered near the apex. Calyx lobes are densely hispid on the margins and abaxial surfaces and are 3-4 mm long at anthesis. The corolla is white to ivory, campanulate, and 5-7 mm long by 4-6 mm wide.

Overview

Species Common Name Silvery phacelia
Species Scientific Name Phacelia argentea
Federal Listing Status Threatened
State Listing Status Threatened

Ecoregions

Columbia Plateau

The Columbia Plateau ecoregion was shaped by cataclysmic floods and large deposits of wind-borne silt and sand earlier in its geological history. It is dominated by a rolling landscape of arid lowlands dissected by several important rivers, and extends from the eastern slopes of the Cascades Mountains, south and east from the Columbia River to the Blue Mountains.

Special needs

Silvery phacelia occurs on unstabilized or semi-stabilized sand dunes, bluffs, and at the bases of coastal headlands. It is found above the high tide line but generally below 65 feet in elevation.

Limiting factors

Habitat loss due to European beachgrass and gorse invasion and urban development is a key threat to this species. Off-highway vehicle use also adversely affects silvery phacelia. The species is extremely vulnerable to climate change, particularly because of predicted sea level rise, natural barriers to movement, and predicted changes to temperature.

Data gaps

Describe life history and biology. Refine propagation and reintroduction protocols.

Conservation actions

Continue efforts to control European beachgrass and manage off-highway vehicle use at occupied sites. Continue to monitor populations.

Key reference or plan

Species Status Assessment: https://iris.fws.gov/APPS/ServCat/DownloadFile/226039