Cyperus alopecuroides, Foxtail Sedge, is a widespread weed in tropical and subtropical areas of the Old World. Carter et al. (Sida 17: 275-281, 1996) first reported it in the United States from Polk County, Florida, where it was locally common in an abandoned phosphate pit (below).  This species has lenticular achenes with the achene face adjacent to spikelet rachilla (right), characteristic of Cyperus subgenus Juncellus.