Crosslandia setifolia is a partly monoecious species of Fimbristylis (Abildgaardieae: Cyperaceae)

Abstract

<p>While the limits of <i>Fimbristylis</i> Vahl (1805: 285) are contentious (Goetghebeur & Coudijzer 1984, Gordon-Gray 1971, Lye 1971, 1973), particularly with regard to the inclusion of <i>Abildgaardia</i> Vahl (1805: 296) within <i>Fimbristylis</i>, all current data support the derivation of <i>Crosslandia</i> W.Fitzg. (1906: 9) from within <i>Fimbristylis</i> (Ghamkhar <i>et al</i>. 2007; Hinchliff & Roalson 2013, Reutemann <i>et al</i>. 2018, Semmouri <i>et al</i>. 2018, Roalson <i>et al</i>. 2019). <i>Crosslandia</i> was described as a monotypic genus in 1906 by Fitzgerald, with more details provided in 1918, where he distinguished <i>Crosslandia</i> from <i>Fimbristylis</i> in having monoecious spikelets and "…the position and structure of the female spikelets." This is clearly a specialized, derived condition from the typically hermaphroditic flowers in monomorphic spikes of <i>Fimbristylis</i>, and it is not, in itself, particularly surprising that monoecy has been derived within <i>Fimbristylis</i>. This has been found in other Cyperaceae genera, including <i>Eleocharis</i> Brown (1810: 224) where there are multiple species with dimorphic inflorescences with monoecious spikes derived from the more typical hermaphroditic flowers in monomorphic spikes (Roalson <i>et al</i>. 2010). In addition, Clarke (2005) found that monoeicy is not always present in specimens referred to <i>Crosslandia setifolia</i>. For these reasons, we provide a new name in <i>Fimbristylis</i> to replace <i>Crosslandia setifolia</i> W.Fitzg. (1906: 9).</p>