Collomia grandiflora is a species of flowering plant in the phlox family known by the common names grand collomia and large-flowered mountain trumpet. This annual herb is native to western North America. It is also cultivated as an ornamental. The plant produces an erect, hairy or fuzzy stem which may be red to green in colour. Arranged at wide intervals along the stem are long, lance-shaped leaves, the lowermost sometimes toothed along the edges. Atop the stem is an inflorescence of several flowers in white to yellow or orange. Each tubular, flat-faced flower is 2 or 3 centimetres wide with 5 curving, light-coloured petals and stamens tipped with anthers which bear blue pollen. The fruit is a capsule containing sticky seeds.
