Cyperus plukenetii Fernald - Plukenet's Umbrella Sedge
Family - Cyperaceae
Stems - Aerial stems to -1m tall, about 2-3mm broad, erect, herbaceous, trigonous (blunt), uniformly pubescent and roughened over their entire length, from very short, knotty rhizomes.
Base of plant.
Leaves - Blades to 60cm long, 3-7mm broad, all basal, present at anthesis, pubescent.
Inflorescence - Terminal umbel with 4-12 rays. Each ray to 15cm long, uniformly roughened and short pubescent over the entire length, 1-2mm broad. Bracts of the inflorescence +/-6, shorter than the rays, pubescent at least on the margins, spreading. Spikes 10-18mm long, with 20-100 spikelets. Spikelets dense, sessile, mostly reflexed, the bases of the spikelets not visible.
Flowers - Spikelets 6-8mm long, narrowly linear, acute to acuminate at the apex, terete to somewhat 4-angled, typically with 3 scales, glabrous, typically shed as an intact unit. Scales 4-4.5mm long, strongly overlapping, lanceolate, acute to acuminate, straw-colored to brown. Fertile florets 1-2 per spikelet. Stamens 3. Anthers .5-1mm long. Stigmas 3. Fruits 2.5-3mm long, narrowly oblong in outline, 3-angled in cross-section, with flat sides, brown, shiny, finely pebbled.
Flowering - July - September.
Habitat - Sand prairies, openings of dry upland woods.
Origin - Native to U.S.
Other info. - This species can be found in just a few southeastern Missouri counties. The plant can be identified by its dense spikes and pubescent-roughened stems and inflorescence rays.
Photographs taken at Fort Benning, GA., 8-11-05.