Montana Field Guide

Yerba Buena is an aromatic perennial herb borne from a woody rootstock with short ascending branches and creeping above-ground stems which often root. The stems and branches are square in cross-section. The leaves are opposite, have short petioles (stalks), are 1-3.5 cm long and oval to almost round in shape, and have bluntly toothed margins and sunken, resin filled dots on the surfaces. Flowers are borne singly on 5-15 mm long pedicels (stalks) in the leaf axils. The calyx is 4-5 mm long and tubular shaped with 12-15 nerves and 5 teeth. The corolla is tubular with distinct short upper and lower lips at its mouth; it is 7-10 mm long, white to cream or purple-tinged, slightly hairy on the outside, and bears 4 stamens on the inside. There is a single pistil with a long slender style (stalk) that has a 2-branched tip.

Flowering in July, fruiting in early August-October.

Distinguished from other mints by combination of creeping stems, bluntly toothed leaf margins, and solitary, axillary, pedicellate flowers, each with a 5-toothed calyx, 2-lipped corolla, and 4 stamens.

Partial or deep shade of moist forests in the montane zone, sometimes in second growth.

POLLINATORS
The following animal species have been reported as pollinators of this plant species or its genus where their geographic ranges overlap: Bombus vagans (Colla and Dumesh 2010).

STATE THREAT SCORE REASON
Threat impact not assigned because threats are not known (MTNHP Threat Assessment 2021).