Cyperus poikilostachys var. heterochrous (Nelmes) Reynders, 2014

Don, Bel Lar Ri, Ers, Enne Th Ba Ut & Reynde, Ma Rc, 2014, Taxonomic changes in C Cyperus (Cypereae, Cyperoideae, Cyperaceae): combining the sedge genera Ascolepis, Kyllinga and Pycreus into Cyperus s. l., Phytotaxa 166 (1), pp. 33-48 : 41

Cyperus poikilostachys var. heterochrous (Nelmes) Reynders , comb. nov.

Basionym: Pycreus heterochrous Nelmes, Kew Bull. 6: 321 (1951 publ. 1952). Type:— ZAMBIA, Mwinilunga District , Matonchi Farm, 0.5 mile South of farm, 24 January 1938, E. Milne-Redhead 4309 (holotype K, isotypes BR!, P!, isotype PRE!).

Description: —Nelmes (1951 publ. 1952: 321)

Note: —Several specimens collected by E. Milne-Redhead in the Zambezian region were simultaneously described as new species by Nelmes, among which P. poikilostachys and P. heterochrous . The latter two species only differ in their glume colour: Pycreus poikilostachys has dark brown glumes and P. heterochrous has pale reddish brown glumes. As both are sympatric with an absence of individuals showing intermediate glume colours, Nelmes (1938) considered both colour variants as different species. Glume colour alone is now considered to be an unreliable character for species delimitation in Cyperus ( Reynders 2013) . In addition, as is known from classic Mendelian genetics, it is possible that different colour variants can be present in the same populations without the presence of intermediates (dominant-recessive inheritance instead of intermediate inheritance). Different colour variants of a single species are usually treated on the variety rank or below.