Cyperus scaettae (Cherm.) 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 : 42

Cyperus scaettae (Cherm.) Reynders

Basionym: Pycreus scaettae Cherm., Rev. Zool. Bot. Afr. 24: 295 (Chermezon 1933 publ. 1934).

Lectotype (designated here):— DEMOCRATIC REPUBLIC OF CONGO, Mubeza, 1930, H. Scaetta 58M (hololectotype BR!, isolectotype K!).

Description: — Hoenselaar et al. (2010: 296).

Note: — Cyperus scaettae belongs to a group of species from Zambezian Africa showing thick accumulations of fibres (remains of leaf sheaths) surrounding the bases of the culms and most often inflorescences are reduced, with only a few spikelets set in a single spike. With the description of different taxa showing these characteristics (e.g. Pycreus fibrillosus , P. scaettae , Fig. 2 ), relatively less attention has been paid to spikelets, glume and nutlet morphology than to the striking culm bases and glume colour. In addition, communication and consultation of type material seemed to have been rather limited in the short period these taxa have been described, combined and synonymised by different authors ( Chermezon 1932, 1933, 1933 publ. 1934, Kükenthal 1921, 1935 –36). Subsequently, species separations and especially synonymisations were not very clear from the beginning and several misinterpretations arose in later publications (e.g. Haines & Lye 1983). Comparision of spikelet characteristics shows Cyperus scaettae clearly differs from C. fibrillosus ( Fig. 2 ).

Figures

FIGURE 2. Comparison of the spikelets (a & c) and rachillas (b & d) of two fibrous “Pycreus” species clearly showing the difference between Cyperus fibrillosus (a & b) and C. scaettae (c & d). Cyperus fibrillosus has a flexuous rachilla that is hardly visible between the glumes. Lower glumes mostly have 1–2 additional nerves on their wings. Cyperus scaettae has larger spikelets with strongly imbricate glumes and a straight rachilla that is visible between the glumes.