In North America, this alien has a similar range to the closely related repens, but tends to occur on drier sites and poorer soils (F, K, W). Distinction can be difficult without complete collections (FNA 3). In addition to its bulbous-thickened stem bases and lack of stolons, bulbosus has sepals reflexed along a well-defined transverse fold 1-3 mm above base (versus spreading, to reflexed from base with age).