Cyperus rotundus L.

Cyperaceae, K Hoenselaar, B. Verdcourt & H. Beentje. Hypolytrum, D Simpson. Fuirena, M Muasya. Flora of Tropical East Africa. 2010

Type

Type: India, Herb. Hermann 1, 3: 36 (BM, lecto., chosen by Tucker in Syst. Bot. Monogr. 43: 100 (1994))

Morphology General Habit

Perennial or sometimes seemingly annual, 10–100 cm tall, gregarious, but not clump-forming, with a somewhat swollen culm-base arising from rather thick scalecovered stolons; nodules on roots white turning brown;  culms few, green, 1–3 mm wide, triangular, glabrous

Morphology Leaves

Leaves glossy green. Leaf blade linear, 10–40 × 0.2–0.8 cm wide, slightly M-shaped in cross-section, scabrid on margin and major veins, attenuate Leaf sheath green to reddish-brown.

Morphology Reproductive morphology Inflorescences Bracts

Involucral bracts leaf-like, 1–5, erect or spreading, lowermost 3–26 cm long, 2–9 mm wide

Morphology Reproductive morphology Inflorescences

Inflorescence a simple to compound anthela, primary branches 1–8, 0.5–12 cm long.

Morphology Reproductive morphology Inflorescences Spikelets

Spikelets in rather dense clusters, 3–15 per cluster, bright to golden to dark brown, linear-lanceolate and slightly flattened, 6–70 mm long, 1–2.5 mm wide, rachilla straight, remaining attached to rachis while lower glumes and nutlets are shed.

Morphology Reproductive morphology Inflorescences Bracts Glume

Glumes pale to dark reddish brown, ovate, 2.7–4.3 mm long, keel green, glabrous or slightly scabrid, with 1–2 veins on either side, apex obtuse

Morphology Reproductive morphology Flowers Androecium Stamens

Stamens 3, yellow, 1.6–2.2 mm long

Morphology Reproductive morphology Flowers Gynoecium Style

Style white, 3-branched

Morphology Reproductive morphology Fruits

Nutlet greyish to brown, obovoid, trigonous, 1.3–1.7 mm long, 0.5–1 mm wide, minutely papillose

Figures

Fig. 32, p212

Ecology

Swamps, damp sites, riverbanks, drainage lines in coastal bush or forest glades, common weed in rice and maize fields, seasonally wet grassland; 0–1950 m

Conservation

Least Concern

Note

After looking at all the East African material available, a few hundred specimens, I believe that for East Africa we are dealing with a single taxon, rotundus, with a few colour forms (and this was the basis on which specimens were mostly sorted, I think), and some variability in spikelet length and cross-section (the latter character used for distinguishing tuberosus) as well as in glume length. I am quite unable to write any key to the various forms that works on the bulk of the material; of course, the extremes are distinct, but there are more intermediate specimens than there are extreme ones. There are no constant qualitative characters separating the taxa, and hardly any convincing quantitative ones, either; geographically and habitat-wise there are no differences. Therefore I am reducing these names into synonyms of rotundus. Regarding the merkeri taxon, C.B. Clarke, when describing his new species C. merkeri only compared it to an unknown taxon, C. neuerensis; he gave the length of the culm as 30 cm. Kükenthal in E.P. 4, 20 (101) combined what was a full species ( merkeri) into a subspecies of rotundus. He did not give a key, but from his brief descriptions we can see he thought this subspecies differed from the typical one in longer culms (45–60 cm rather than 15–30 cm), and darker-coloured spikelets (dark dull red, rather than brown or dull red). Haines & Lye distinguished these two subspecies (again, without giving a key) by ‘its shorter glumes with a usually much darker colour’: glumes 2.7–3.2, rather than 3.3–4.3 mm; description of glume colour in the text overlaps for the two subspecies. Haines & Lye kept up four subspecies and varieties, based on Kükenthal taxa; Kükenthal had combined these taxa into C. rotundus. Differences between the taxa were only expressed in short sentences (rather than a key) and these have given me problems. Colour and degree of compression of the spikelet, plus glume length and glume apex configuration, were the characters used to distinguish these four taxa. Finally the taxon tuberosus was distinguished from rotundus by the original author, Rottbøll, based on a leafy (not almost leafless) culm base, a sub-simple anthela, and terete spikelets. Haines & Lye suggested that this subspecies “is very closely related to subsp. rotundus” but kept the taxa separate based on slightly longer and more acute glumes, and less terete spikelets, in tuberosus. A taxon decribed from coastal Kenya, var. taylorii, was said to differ in the tall culms (30–50 cm, quite within the range of typical rotundus); the large congested head, 3–6 cm wide of many crowded up to 3 cm long spikelets (again, well within normal range) and obtuse glumes 4–5 mm long (rather on the long side, but not excessively so). It was known only from the type.

Distribution

Range: Widespread in Africa; India Flora districts: U1 U2 U3 U4 K1 K2 K3 K4 K5 K6 K7 T1 T2 T3 T4 T5 T6 T7 T8 Z

Vernacular

Coquito, Corocillo

Bernal, R., Gradstein, S.R. & Celis, M. (eds.). 2015. Catálogo de plantas y líquenes de Colombia. Instituto de Ciencias Naturales, Universidad Nacional de Colombia, Bogotá. http://catalogoplantasdecolombia.unal.edu.co

Distribution

Naturalizada en Colombia; Alt. 0 - 1000 m.; Islas Caribeñas, Llanura del Caribe, Valle del Cauca, Valle del Magdalena.

Morphology General Habit

Hierba

Conservation

Preocupación Menor

M. Thulin et al. Flora of Somalia, Vol. 1-4 [updated 2008] https://plants.jstor.org/collection/FLOS

Morphology General Habit

Medium-sized perennial with a somewhat swollen (sometimes tuber-like) stem-base arising from slender to fairly robust stolons with rather remote scales

Morphology Stem

Stems 25–80 cm long and 1–4 mm thick, glabrous, triangular with many crowded leaves in the basal part

Morphology Leaves

Largest leaf-blades 15–40 cm long and 4–8 mm wide, flat or enrolled, scabrid at least on margin and major ribs; leaf-sheaths green to brown

Morphology Reproductive morphology Inflorescences

Spikes 1–5 x 1.5–7 cm with 4–15 erect or spreading spikelets Inflorescence a 3–15 cm long and 2–12 cm wide anthela consisting of 1(–many) sessile and 1–8 stalked spikes on 0.5–12 cm long peduncles with or without secondary spikes from the base of primary spikes; inflorescence-bracts 1–7, leafy, erect or spreading, the largest 3–20 cm long and 2–9 mm wide

Morphology Reproductive morphology Inflorescences Spikelets

Spikelets 6–70 x 1–2.5(–4) mm, linear-lanceolate, light to dark reddish brown with 8–35 flowers

Morphology Reproductive morphology Inflorescences Bracts Glume

Glumes 2.7–4.3 mm long, ovate, almost uncoloured or light to dark reddish brown with or without a narrow uncoloured margin and 1–2 nerves on each side of the midrib; midrib green, glabrous or scabrid ending in or below the obtuse apex

Morphology Reproductive morphology Flowers Gynoecium Style

Style 3-branched

Morphology Reproductive morphology Fruits

Nutlet 1.5–1.8 x 0.7–1 mm, obovate, triangular, greyish, minutely papillose.

Distribution

N2, 3; C2; S1–3 pantropical, andtemperate regions.

Ecology

Near sea-level to 500 m.

Vernacular

Gocondho, quunje (Somali).

Note

This is a very variable species, particularly as regards the colour and size of the glumes. The following subspecies apparently occur in Somalia: subsp. rotundus with 3.3–4.3 mm long light to dark reddish brown glumes, subsp. tuberosus (Rottb.) Kük. with 3.7–4 mm long light brown to uncoloured glumes, and subsp. merkeri (C.B. Cl.) Kük. with 2.7–3.2 mm long dark reddish brown to almost blackish glumes. Most collections are, however, too young to be referable to any of the subspecies.

M. Thulin et al. Flora of Somalia, Vol. 1-4 [updated 2008] https://plants.jstor.org/collection/FLOS

Morphology General Habit

Robust perennial producing solitary stems from the end of 5–10 cm long and 1–2 mm thick stolons with 10–15 mm long prominent scales

Morphology Stem

Stem 30–60 cm long and 2–5 mm thick, triangular, glabrous

Morphology Leaves

Leaves usually 4–5 from the basal 10–20 cm; the sheaths grey, wide and loose; blades 15–30 cm long and 7–10 mm wide, flat, scabrid on margin and midrib

Morphology Reproductive morphology Inflorescences

Inflorescence a 5–15 cm long and 4–15 cm wide lax anthela consisting of 1 sessile spike subtended by 2–10 stalked spikes or new groups of sessile and stalked spikes on up to 12 cm long peduncles; involucral bracts usually 3, leafy Spikes 1–3 x 2–4 cm with 5–10 spreading spikelets

Morphology Reproductive morphology Inflorescences Spikelets

Spikelets 6–15 x 2–3 mm, linear or linear-lanceolate, spreading

Morphology Reproductive morphology Inflorescences Bracts Glume

Glumes 3.5–4 mm long, ovate, greyish to medium reddish brown with a pale marginal border and a green midrib excurrent into a short straight or recurved mucro; lateral nerves 3–4

Morphology Reproductive morphology Flowers Gynoecium Style

Style 3-branched

Morphology Reproductive morphology Fruits

Nutlet c. 1 x 0.6 mm, obovate, triangular, as young brownish, as mature dark grey to almost black, minutely papillose.

Distribution

N1, 2; Sudan

Ecology

Altitude range 15–930 m.

Cyperaceae, Miss S. S. Hooper. Flora of West Tropical Africa 3:2. 1972

Diagnostic

Similar to C. rotundus Linn. but with somewhat laxer spikes of more numerous acute spikelets of longer, lanceolate, acute glumes

Ecology

Damp grassy and waste places.

M. Thulin et al. Flora of Somalia, Vol. 1-4 [updated 2008] https://plants.jstor.org/collection/FLOS

Type

N3, “Dudo” in “Shol” plain, Merla, Azzaroli & Fois s.n. (FT holo.)

Morphology General Habit

Robust perennial; stems 30–40 cm long and 1.5–3 mm thick

Morphology Leaves

Leaf-blades to 40 cm long and 4-8 mm wide, flat

Morphology Reproductive morphology Inflorescences

Inflorescence a lax anthela to c. 10 cm long and wide, consisting of many sessile as well as stalked spikes or clusters of spikes Spikes c. 2 x 3–4 cm, consisting of 4–10 spikelets mostly spreading at right angles; rhachis 1–5 mm long

Morphology Reproductive morphology Inflorescences Spikelets

Spikelets 15–22 x 3–4 mm, linear, 20–25-flowered; rhachilla prominently zigzag with rather widely spaced flowers

Morphology Reproductive morphology Inflorescences Bracts Glume

Glumes 3–3.5 mm long, ovate, reddish brown without pallid margin, with 3–5 slender nerves on each side of the green midrib which is excurrent into a c. 0.2–0.3 mm long mucro

Morphology Reproductive morphology Flowers Gynoecium Style

Style 3-branched

Morphology Reproductive morphology Fruits

Nutlet 1.8 x 0.7–0.8 mm, obovate, prominently triangular, greyish, minutely papillose.

Distribution

N3 not known elsewhere.

Ecology

Altitude range 350–400 m.