Primula mistassinica Michx.
Habitat: Calcareous or argillaceous rocks, shores, and meadows. [Non-tidal rivershore (non-forested, seasonally wet)]
Range: Labrador to Alaska, south to Newfoundland and Maine, and west through Wisconsin and Alberta to British Columbia.
Aids to Identification: One of the few flowers to be seen blooming along the rivershores of northern Maine so early in spring. The flowers, standing only 5-10 cm from the ground, are borne on a leafless stalk, called a scape, and occur either singly or in loose clusters. They range in color from palest pink to deep rose and have five petals which are notched at the tip and are 1-2 cm in diameter. Where the petals meet in the center, there is a conspicuous yellow eye. The leaves are small and grow in a basal rosette (the whole rosette usually only about 1-3 cm in diameter) and are green on both sides, short-stalked or sessile, and toothed. It is distinguished from P. laurentiana (also rare, and typically but not always coastal) by its shorter sepals (3-6 mm compared to 6-9 mm), and its bracts beneath the umbel are barely, if at all, saccate at their base.
Ecological characteristics: P. mistassinica is rare in Maine because it is at the southern limit of its range and because of the natural scarcity of habitat. Where it does occur, however, it may be locally common. It is found in numerous places along the St. John River, for example, though it is confined to the wettest, seepiest spots, either on gravel or on ledge. It often occurs with other rare and unusual calciphiles.
Phenology: One of the earliest of the spring flowers, blooming from early to late May (southwards) into the beginning of June in northernmost Maine. Peak bloom coincides with peak canoeing season along the St. John. Easily overlooked when not in flower.
Synonyms: Primula intercedens Fern.; Primula mistassinica Michx. var. intercedens (Fern.) Boivin; Primula mistassinica Michx. var. noveboracensis Fern.
Known Distribution in Maine: This rare plant has been documented from a total of 24 town(s) in the following county(ies): Aroostook, Piscataquis, Somerset.
Reason(s) for rarity: At southern limit of range and calcareous habitat naturally scarce.
Conservation considerations: Maintain hydrologic integrity of its rivershore habitat, including the natural disturbance by water and ice. Populations along rivershores could be harmed if all-terrain vehicle use of the habitat increases.