THE DISCOVERY OF RHEXIA MARIANA L. VAR. MARIANA (MELASTOMATACEAE) IN NORTHWEST INDIANA

摘要

Significance of the Report. Prior to this collection, Rhexia mariana var. mariana had not been documented in northern Indiana or in the 22-county Chicago region, as defined in Swink and Wilhelm (1994) and Wilhelm and Rericha (2017). Previous Knowledge. Rhexia mariana L. var. mariana (Melastomataceae), the Maryland meadow beauty (Figure 1), is a perennial herb of dry to moist sandy soil and full to partial sun conditions, occurring primarily in sandhills, savannas, flatwoods, meadows, marshes, ditches, bogs, edge of thickets, and upper shores of ponds and swales (Correll and Johnston 1979; Radford et al. 1968; Voss and Reznicek 2012; Wunderlin and Hansen 2003). It is one of several species with a core geographical distribution along the Gulf of Mexico and Atlantic Ocean coastal plains (in this case reaching from Texas to Massachusetts) and with disjunct populations around the Great Lakes (in this case in southwest Michigan prior to the recent collection) (Reznicek 1994); the core of the range of R. mariana var. mariana stretches inland to southeastern Missouri, southern Illinois, and southern Indiana (Kartesz 2015; USDA, NRCS 2018). Although it had not been documented from the 22-county Chicago region prior to this collection (Kartesz 2015; Swink and Wilhelm 1994), R. mariana var. mariana is extant in Allegan and Ottawa counties in Michigan, just north of the easternmost extent of the Chicago region (Voss and Reznicek 2012). In Indiana, R. mariana var. mariana was known from the southern third of the state, where it formed the boundary of the known core of its coastal plain distribution (Deam 1940; Kartesz 2015). Across its range, R. mariana var. mariana is globally secure (G5T5), but at the edge of its range in Indiana, it is critically imperiled (S1) and state threatened, and in the disjunct portion of its range in Michigan it is critically imperiled to imperiled (S1S2) and state threatened (IDNR-DNP 2016; Michigan Natural Features Inventory 2007; NatureServe 2017).