Sisyrinchium mucronatum Michx.
Family: Iridaceae
needle-tip blue-eyed-grass
[Sisyrinchium angustifolium var. mucronatum Mill.,  more...]
Sisyrinchium mucronatum image
from USDA Plants website  
Etymology: Sisyrinchium: Greek sys for pig; rynchos for snout; referring to a pig grubbing the roots for food
Plants: erect, perennial, to 20" tall forb, delicate, wiry, light olive to yellowish when dry; often forming small clusters; stems thin, winged, branched, bending at the 1st or 2nd nodes
Leaves: narrow, smooth, up to 1/8" wide, shorter than the stem
Flowers: light blue to violet, 6-parted, 1/2" - 3/4" wide, tepals sometimes white, bases yellow, tips notched to blunt with a sharp point; inflorescence of 1 cluster from the leaf axils, 2 sheaths (spathes), usually green sometimes with purplish edges, wider than the stalk, connected at the base, outer sheath 1/2" long; blooms June-July
Fruits: small, roundish, dark-brown to purplish-black capsule
Habitat: moist; meadows, streambanks, open woods