Evolution in sedges (Carex, Cyperaceae)

REZNICEK, A. A. 1990. Evolution in sedges (Carex, Cyperaceae). Can. J. Bot. 68: 1409-1432. Carex is the largest and most widespread genus of Cyperaceae, but evolutionary relationships within it are poorly understood. Subgenus Primocarex was generally thought to be artificial and derived from diverse multispicate species. Relationships of rachilla-bearing species of subgenus Primocarex, however, were disputed, with some authors suggesting derivation from other genera, and others believing them to be primitive. Subgenus Indocarex, with compounded inflorescence units, was thought to be primitive, with subgenera Carex and Vignea reduced and derived. However, occurrence of rachillas is not confined to a few unispicate species, as previously thought, but is widespread. The often suggested connection between Uncinia and unispicate Carex is shown, based on rachilla morphology, to be founded on incorrect interpretation OF homology. Uncinia kingii, the alleged connecting link, is, in fact, a Carex. Unispicate Carex without close multispicate relatives probably originated from independent, ancient reductions of primitive, rachilla-bearing, multispicate Carex. The highly compounded inflorescences occumng in subgenus Vignea are hypothesized to represent a primitive state in Carex, and the more specialized inflorescences in subgenus Carex derived from inflorescences of this type. The relationships of subgenus Indocurex, with its unique perigynium-like inflorescence prophylls, remain unclear.