Pollen morphology of Xyridaceae (Poales) and its systematic potential

Xyridaceae are a predominantly tropical family of five genera that exhibit two pollen morphologies often considered to be of taxonomic importance. Xyris comprises about 95% of the species and is characterized by medium to large, elliptic, sulcate pollen grains. The other pollen class is spheroidal grains without an evident aperture. Many of the species with spheroidal grains have remarkably large and ornamented pollen found to be species specific in earlier research. A scanning electron microscopy investigation of 23 taxa representing all genera with spheroidal pollen revealed new data to further distinguish the genera based on pollen characters. Reliable specific pollen characters need to be evaluated in a statistical study. Keywords Clypeate * Inaperturate * Omniaperturate * Scanning electron microscopy
Xyridaceae (Poales) are a predominantly tropical and subtropical family of five genera and about 415 species (Kral, 1998; Campbell, 2004a; 2008). The family is most speciose in South America where [...]