Cyperus papyrus L.

Large, emergent, aquatic perennial.  Rhizomes short, covered in thick, black scales.  Roots tough, extending 1m or more in suitable conditions.  Rootlets numerous.  Culms erect to 5m, 5 (-6)cm across at the base (widest point), smooth, trigonous (angles very rounded, particularly on lower parts), green (photosynthetic); spreading when old.  Pith solid, white-light brown, vascular bundles prominent.  Leaves reduced, sheathing and restricted to basal ±50cm of culms; reddish-blackish brown when young; expanding with age and colours restricted to lateral edges sub-marginally; tough, margins scarious; becoming papery, colours fade and sheaths split ventrally with age.  Inflorescence large (30-) 50 (-60)cm diameter, compound, umbel-like, hemispherical when young, becoming sub-globose with age.  Some inflorescences smaller, entirely sterile, or minutely fertile.  Bracts (B1) variable, 10-15 (-17)cm long, (10-) 12-25mm wide at base; broadly triangular to triangular-attenuate; reddish dorsally in bud, becoming green then papery and brown with age; patent to slightly recurved.  Rays “branches”, (R1) 50-150, sub-equal, smooth, green, (15-) 20-30 (-35)cm long, thin (2) 3-4 (5)mm wide, trigonous to triquetrous apically, flexible; with basal, sheathing, dark brown tipped, red-veined prophylls (P1) 2-2.5cm.  Spikes (S1) terminal on rays, in small umbel-like clusters (1-) 3 (-4), length 2 – 3cm, elongate-cylindrical; subtended by  3 (-4) bracteoles (B2), (5-) 10-15 (-16)cm long, thin, wiry, green, trigonous; rough-scabrid in one direction, apex to base.  Rachillas (R2), unequal 0-1cm to first spikelet; winged; with basal, short, sheathing prophylls (P2).  Spikelets (S2) arranged spirally, sessile, oblong to oblanceolate, flattened to sub-terete; minute basal bract (B3), 0.3-0.4cm, lanceolate to sub-ovate; ovate, with basal, semi-sheathing prophyll (P3) 0.4-0.6cm.  Florets (F1), bisexual, arranged distichously, 4 – 8 (-10). Glumes 1-2mm, blunt to mucronulate.  Scales “rachilla wings” 1mm, chaff-like, brown, lanceolate, curling on drying.  Style long; stigmas 3, long, protruding, persistent.  Ovary superior, one-celled.  Stamens 3, filaments fine, elongating; anthers (0.8-1.2mm), basifixed, bilocular, caducous; connective tissue distinct, red, with an apical extension ± 0.1mm.  Nutlets 3-angled, 0.8-1.3mm, brownish-black, oblong, sometimes concave ventrally, shortly apiculate, with short-lived, translucent  .