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.
Habitat: Weedy areas, overgrown fields.
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