This is widespread across eastern and central North America, except on most of the southeastern Coastal Plain (where it does extend locally on base-rich soils). It is more widespread than claytonii but more concentrated on base-rich soils, where the woods tend to be more disturbed. Dispersal may occur in fur of large herbivores (Wen et al. 2002). O. longistylis differs from claytonii as follows (W): styles plus stylopodium 2.0-3.5 mm long (versus 0.5-1.5 mm); flowers usually 9-18 per umbellet, including withering staminate flowers (versus 4-7); flowers 5-6 mm across (versus 3-4 mm); umbellets usually 4-6 per umbel (versus 3-5), on rays usually 1.5-5 cm long (versus 2-8 cm), the umbel thus more crowded; roots and foliage with strong anise or licorice scent (versus little or anise scent but often mild carrot scent). O. longistylis is well known to be a culinary or medicinal herb among native people (Moerman 2009), which may be partly associated with anethole (the phenylpropene derivative that imparts "anise" flavor), falcarindiol (combining polyacetylene and polyyne structure for "carrot" flavor), and related compounds (e.g. Kern & Cardellina 1982). No toxicity is reported. The genus is generally considered a preferred food for mammalian herbivores, including cattle, sheep, deer and rabbits (e.g. Stephens & Monsen 2004; pers. obs. for rabbits on longistylis). The allied monotypic species, Myrrhis odorata Mill,, is a Europaean native that has been widely grown for culinary use (as "sweet cicely" or "garden myrrh"); in North America escapes have been reported from some northern states and adjacent Canada (K).