Marshallia mohrii is an erect, perennial herb, 3-7 dm (1-2.3 ft.) tall. Leaves are alternate, 8-20 cm (3.2-7.8 in.) long, firm-textured, three-nerved, and lanceolate-ovate in shape. Leaves are often clustered near the base of the plant and gradually reduce in size upwards. Inflorescences typically consist of several flowering heads in a branched arrangement. Heads are approximately 2.5 cm (1 in.) wide and consist of disk flowers (tubular in shape) that are pale pink or white in color. The fruit is an achene.