This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol1", by Nathaniel Lord Britton, Addison Brown. Also available from Amazon: An Illustrated Flora of the Northern United States, Canada and the British Possessions. 3 Volume Set..
Annual or perennial sedges, with slender triangular culms, leafy below, and with 2 or more leaves at the summit forming an involucre to the strictly sessile, simple or compound dense head of spikelets. Spikelets numerous, compressed, falling away from the axis of the head at maturity, consisting of only 3 or 4 scales, the 1 or 2 lower ones small and empty, the middle one fertile, the upper empty or staminate. Joints of the rachis wingless or narrowly winged. Scales 2-ranked, keeled. Perianth none. Stamens 1-3. Style 2-cleft, deciduous from the summit of the achene. Achene lenticular. [In honor of Peter Kylling, a Danish botanist of the seventeenth century.]
Kyllingia pumila Michx. Fl. Bor. Am. 1: 28. 1803.
Annual, culms densely tufted, filiform, erect or reclined, 2'-15' long, mostly longer than the leaves. Leaves light green, roughish on the margins, usually less than 1" wide, those of the involucre 3-5, elongated, spreading or reflexed: head oblong or ovoid-oblong, 3"-4" long, simple or commonly with 1 or 2 smaller ones at the base; spikelets about 1 1/2" long, flat, 1-flowered, the 2 empty lower scales more or less persistent on the rachis after the fall of the rest of the spikelets; scales ovate, acuminate or acute, thin, about 7-nerved, the fertile one with a rough keel; stamens 2; style 2-cleft; achene lenticular, obtuse.
In moist or wet soil. Delaware to Florida, Illinois, Kansas, Texas and Mexico; West Indies and tropical continental America. Aug.-Sept.