This northeastern species extends south on the Coastal Plain to S.Car. (FNA 23, W). It has been reported from Ky. by Campbell et al. (1992) and others from slightly open seepy or swampy woods, but perhaps based only on misidentified variants of tribuloides or sangamonensis. C. projecta appears somewhat intermediate between tribuloides and cristatella (FNA 23), but can be distinguished from both by its inflorescence flexible or nodding, and its perigynia usually less numerous and more spreading; 2n = 64 (versus 70). FNA 23 also stated: "when all three species occur together, C. projecta flowers and fruits first, C. tribuloides later, and C. cristatella latest of all. When C. projecta is in mature fruit, C. cristatella will be just past flowering." Although there are no confirmed records of projecta from Ky., some plants mapped here under sangamonensis are hard to distinguish, especially colls. with slightly nodding spikes and relatively broad yellowish-green leaves. Such colls. are mostly from eastern regions of the state, along smaller streams and seeps with acid soils. Similar plants are known from Tenn. (e.g. at MO: R. Kral #52740 from Cheatham Co.); and the status of projecta in Tenn. also remains somewhat uncertain.