Cyperus waillyi (Cherm.) Lye

Extinction risk predictions for the world's flowering plants to support their conservation (2024). Bachman, S.P., Brown, M.J.M., Leão, T.C.C., Lughadha, E.N., Walker, B.E. https://nph.onlinelibrary.wiley.com/doi/full/10.1111/nph.19592

Conservation

Predicted extinction risk: not threatened. Confidence: confident

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

Type

Type: Mali, Gao to Berra, De Wailly 5340 (P, holo.)

Morphology General Habit

Annual to 33 cm long, slender, completely submerged under water.

Morphology Culms

Culm ± 25 cm long, ± 0.7 mm wide, trigonous, smooth

Morphology Leaves

Leaf blade linear, flat, ± 8–18 cm long, 1 mm wide, acuminate, glabrous Leaves up to 20 cm long. Leaf sheath strawcoloured yellow, 2.5–4 cm long.

Morphology Reproductive morphology Inflorescences Bracts

Involucral bracts 2–3. Leaf-like, 10–11 cm long, 0.8–1.2 mm wide

Morphology Reproductive morphology Inflorescences

Inflorescence of one sessile spikelet and 4–5 stalked spikelets.

Morphology Reproductive morphology Flowers Pedicel

Pedicels 5–8.5 cm long.

Morphology Reproductive morphology Inflorescences Spikelets

Spikelets linear-oblong, 8–12 mm long, 1.7–2 mm wide, axis straight to ± curved.

Morphology Reproductive morphology Inflorescences Bracts Glume

Glumes ovate, reddish-brown, 1.8–2.1 mm long, 1.4–1.6 mm wide, keel rounded, apex rounded to obtuse, glabrous

Morphology Reproductive morphology Flowers Androecium Stamens

Stamens 2

Morphology Reproductive morphology Flowers Gynoecium Stigma

Stigma 2-branched

Morphology Reproductive morphology Fruits

Nutlet shiny black, orbicular, biconvex, 1.1–1.2 mm long, 0.9–1 mm wide, minutely papillose

Ecology

Submerged in stream; 2150 m

Conservation

Data Deficient (DD). Very few collections throughout tropical Africa. Probably data deficient due to its habitat and therefore undercollected. There is no information about the status of the habitats in which the plants occur.

Distribution

Flora districts: T7 Range: Mali, Congo-Kinshasa

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

Morphology Reproductive morphology Inflorescences

Submerged or floating with an inflorescence of spikelets borne singly

Ecology

In shallow water.

J. Browning, K.D. Gordon-Gray†, M. Lock, H. Beentje, K. Vollesen, K. Bauters, C. Archer, I. Larridon, M. Xanthos, P. Vorster, J. Bruhl, K. Wilson and X. Zhang (2020). Flora Zambesiaca Volume: 14: Cyperaceae. M.Á. García, J.R. Timberlake (Eds). Kew Publish

Type

Mali, Gao to Berra, Marigot, 19.ii.1937, de Wailly 5340 (P holotype, IFAN, K).

Morphology General Habit

Annual, submerged in flowing streams with only inflorescence held above water; culms 1–10, to 80 cm long and to 1.5 mm wide, rounded, striate, smooth

Morphology Leaves

Leaf sheaths brown, to 2 cm long; blade linear, flat, to 20 cm long and to 1.5 mm wide, scabrid near tip

Morphology Reproductive morphology Inflorescences

Inflorescence to 5 × 4 cm, consisting of 1–3 subsessile spikelets with 5–10 stalked clusters, each with 1–3 spikelets with an inflated peduncle 1–4.5 cm long; involucral bracts 2–5, leaf-like, thin and flaccid, largest 10–22 cm long and 1–2 mm wide, scabrid near apex

Morphology Reproductive morphology Inflorescences Spikelets

Spikelets 5–13 × 2–3 mm, linear-lanceolate; glumes appressed at flowering, spreading later, very tardily dehiscing at maturity, densely imbricate (about 2/3 overlapping), reddish brown or to dark brown, broadly ovate to elliptic, without hyaline margin, 1.5–2 × 1.5 mm, obtuse with midrib reaching the tip, keel prominent, rib-like, pale green

Morphology Reproductive morphology Fruits

Nutlet black, ellipsoid to subglobose, apex subacute, apiculate, 1 mm long, weakly transversely ridged.

Distribution

Botswana, Zambia. Also in Mali, D.R. Congo and Tanzania.

Ecology

Submerged in streams or creeping on drying mud; 950–1100 m.

Conservation

Data Deficient. Only a few collections spread through a vast area. Almost certainly very undercollected.