Pycreus polystachyos (Rottb.) Domin
Vascular – Exotic
Tufted yellow-green leafy sedge, with triangular stems up to 50 cm tall, leaves arranged in threes, with up to 7 upright yellow-green to pale brown ragged flowerheads, each made up of narrow flattened flower spikes, with 3 to 6 long grass-like leaves immediately under this, at the end of flower stalk.
Restricted to Northland and Auckland where it is locally common.
Wet pasture, margins of water bodies and drains.
Densely tufted annual to perennial. Stems to 50 cm tall, 3-angled, leafy at base. Leaves < stems, 2-3 mm wide, smooth; sheaths purple-brown, sometimes with a few transverse septa. Involucral bracts 3-6, leaf-like, > inflorescence. Inflorescence capitate or with rays to 4 cm long. Spikelets ± stiffly erect in rather dense clusters, narrow-linear, acute, ± 15 × 1.5 mm. Glumes ± 2 mm long, densely imbricate, membranous, subobtuse, chestnut or straw-coloured with green keel. Stamens 2. style-branches 2. Nut ± ½ length of glume, oblong, compressed-biconvex, brown.
Similar to and often growing with Cyperus eragrostis and C. congestus, differring by the upright, close set inflorescence, the flowerheads are not globular.
Summer to autumn
Summer to autumn
Seed dispersed by contaminated machinery.
Pantropical and subtropical, also more temperate Australia
Reason for introduction
Unknown, possibly ornamental plant, seed or soil contaminant.
Not controlled in New Zealand.
cyperus: From the ancient Greek name for sedge, kypeiros
Factsheet prepared by Paul Champion and Deborah Hofstra (NIWA). Features description from Healy and Edgar (1980).
References and further reading
Healy, A.J.; Edgar, E. (1980). Flora of New Zealand, Volume III. Adventive Cyperaceous, Petalous and Spathaceous Monocotyledons. Government Printer, Wellington. 220pp.
Johnson PN, Brooke PA (1989). Wetland plants in New Zealand. DSIR Field Guide, DSIR Publishing, Wellington. 319pp.
Champion et al (2012). Freshwater Pests of New Zealand. NIWA publication. http://www.niwa.co.nz/freshwater-and-estuaries/management-tools/identification-guides-and-fact-sheets/freshwater-pest-species