Inflorescence and floral characters indicating C<sub>3</sub> and C<sub>4</sub> photosynthesis in some species of the genus <i>Cyperus</i> L. (Cyperaceae)

Abstract

Inflorescence and floral morphological characters in twelve species of Cyperus – a genus known to have C 3 and C 4 photosynthetic species – were investigated in order to check their usefulness in delimiting species into photosynthetic groups. Plant species were collected from different locations within Southwestern Nigeria. Qualitative characters were noted and recorded while some quantitative characters were measured with metric ruler to the nearest centimeter and others were counted. The results revealed that compound umbellate inflorescence, digitately arranged spikelets and short spikelets not over 1cm long are characters that separate C. difformis and C. haspan which are C 3 species, while the rest with simple umbellate inflorescence, spicate spikelets and spikelet length over 1cm are C 4 species. Cyperus dilatatus , a species without a previous record of photosynthetic grouping, is hereby grouped as a C 4 species since it shared characters with the rest C 4 species. From this study, a combination of characters was identified, which can possibly be used along with known data from other sources in the grouping of Cyperus species as either C 3 or C 4 species. Data on C. dilatatus also showed that it possibly belong to C 4 species. This is probably the first known report on photosynthetic grouping of this species. © 2015 International Formulae Group. All rights reserved. Keywords: C 3 - C 4 species, Cyperus genus, inflorescence morphology, photosynthetic grouping, taxonomy