Description
Mealy Primrose is slender, tall, and heavily farinose, or occasionally efarinose. It rises up to 46 cm high, and leaves are elliptic or oblanceolate, including the petioles, which are up to 6 cm long. Blades are 0.3-1.6 cm wide with denticulate margins and gradually narrow into a broadly winged petiole. The involucral bracts are 0.5-1 cm long, oblong, densely covered with white farina, flat above, and saccate or gibbous at the base. The umbels are capitate, 7-19 flowered, and the pedicels are short and 0.3-0.9 cm long. Flowers are homostylous. The calyx is green, heavily farinose, cylindrical, obscurely ribbed, and 0.4-0.7 cm long; it is divided up to one third its length by lanceolate teeth that are covered with capitate 3-4 celled glands. The corolla is lavendar with a yellow throat. The limb is 0.4-0.8 cm wide, emarginate, and is a tube that is equal to or slightly longer than the calyx. Stamens are ca. 1 mm long and located in the upper portion of the corolla tube. The stigma is capitate and located adjacent to the anthers. The capsule is cylindrical to slightly elliptical, 0.2-0.3 cm wide, and 1.5-2 times the length of the calyx. Seeds are brown, reticulate, ca. 0.2 mm long.
Diagnostic Characteristics
P. INCANA is a generally well-marked species with heavily farinose leaves, tall scape, and flat-tipped bracts subtending tight umbels of small homostylous flowers. Many northern collections have been misidentified as the smaller P. STRICTA because flowering begins when the scape is relatively short. Elongation of the scape continues throughout anthesis, and pedicels lengthen as seeds ripen. Thus, the characteristic tight umbels do not persist beyond anthesis, and individuals in the fruiting stage may be many times taller than those in early flowering stage. P. INCANA is most similar to P. LAURENTIANA. The latter is distinguished by having larger flowers, longer pedicels, broader, more denticulate leaves, and involute rather than flat bracts.