This section is from the book "Nature's Garden", by Neltje Blanchan. Also available from Amazon: Nature's Garden; An Aid To Knowledge Of Our Wild Flowers And Their Insect Visitors.
Flowers - Creamy white, delicately veined with greenish, solitary, 1 in. broad or over, at the end of a scape 8 in. to 2 ft. high, 1 ovate leaf clasping it. Calyx deeply 5-lobed; corolla of 5 spreading, parallel veined petals; 5 fertile stamens alternating with them, and 3 stout imperfect stamens clustered at base of each petal; 1 very short pistil with 4 stigmas. Leaves: From the root, on long petioles, broadly oval or rounded, heart-shaped at base, rather thick.
Flowering Season - July - September.
Distribution - New Brunswick to Virginia, west to Iowa.
What's in a name? Certainly our common grass of Parnassus, which is no grass at all, never starred the meadows round about the home of the Muses, nor sought the steaming savannas of the Carolinas. The European counterpart (P. paliistris), fabled to have sprung up on Mount Parnassus, is at home here only in the Canadian border States and northward.
At first analysis one is puzzled by the clusters of filaments at the base of each petal. Of what use are they? We have seen in the case of the beard-tongue and the turtle-head that even imperfect stamens sometimes serve useful ends, or they would doubtless have been abolished. A fly or bee mistaking, as he well may, the abortive anthers for beads of nectar on this flower, alights on one of the white petals, a convenient, spreading landing place; but finding his mistake, and guided by the greenish lines, the pathfinders to the true nectaries situated on the other side of the curious fringy structures, he must, because of their troublesome presence, climb over them into the centre of the flower to suck its sweets from the point where he will dust himself with pollen in young blossoms. Of course he will carry some of their vitalizing powder to the late maturing stigmas of older ones. Without the fringe of imperfect stamens, that serves as a harmless trellis easily climbed over, the visitor might stand on the petals and sip nectar without rendering any assistance in cross-fertilizing his entertainers.