Bladder Campion

Bladder Campion
Bladder Campion. Silene vulgaris.
Caryophyllaceae, the pink family.

Plant: Erect, flowering stems, 6"-24" tall bear small clusters of white flowers with an inflated, balloon-like base. Perennial.
Flowers: White, 1/2"-3/4" across, with five petals so deeply notched as to appear as ten, emerging from the summit of an inflated, smooth, balloon-like calyx, marked with pinkish veins. Flowers are borne in a small cluster (cyme), atop a stiff stem. Three styles extend well beyond the petals.
Leaves: Opposite, ovate to lanceolate, sessile, entire, 1.5"-4" long, sometimes clasping the stem
Fruit: A papery husk derived from the expanded calyx.
Blooming: May-August
Habitat: Weedy areas, overgrown fields.

Comments: The smooth, balloon-like calyx gives this species its common name. Native to Eurasia, it has spread across much of the Northeast US and Southern Canada.

Where to find it: Relatively uncommon in the park, I have found it only in one location, a weedy patch consisting mainly of spotted knapweed just west of the west perimeter trail about 100 yards from the lodge. The closely related White Campion (Silene latifolia) is much more common.