A New Species of Hydrophyllum from the Ouachita Mountains of Arkansas

Abstract

In early May of 1979, during some fieldwork in the Ouachita Mountains in southwestern Arkansas, a small population of a Hydrophyllum was found on rocky, hardwood-forested bluffs along the Cossatot River (Howard County, 8 May 1979, R. Kral 63510). This was recorded and later again determined to be H. macrophyllum Nuttall. Checking the descriptions, statements on ecology, and distribution given in recent revisional work by Constance (1942) and Beckmann (1976, 1979) appeared to confirm the identification of the plant as H. macrophyllum, a species of the Central Plains and Appalachian provinces. Statements of range for H. macrophyllum as given by these two authors differ slightly, both showing a distribution of this mesophyte from the Central Lowlands of Illinois, Indiana, Ohio, southward through the Appalachians to western North Carolina in the east, and with western limits from southern Illinois southward through Kentucky, central Tennessee, and northern Alabama. However, Beckmann, in his citations of specimens, indicated an Arkansas record (1976: 366), Arkansas. Montgomery Co.-Albert: rich woods, Demaree 36687 (GH), the given there ostensibly representing the Albert Pike Recreation Area or its vicinity in the Ouachita National Forest. Nonetheless, the Howard County find was thought to be a recent and unpublished record for Arkansas, and a check of Smith's (1978) atlas was made. According to Smith, the species had been reported for Arkansas by Dwight Moore as early as 1951, and there were currently five counties known for it. Thus the investigation ended, the Howard County specimen was routinely filed at the Vanderbilt University Herbarium (VDB), and the matter was forgotten. Several years later, in 1988, another Hydrophyllum specimen from the Arkansas Ouachitas was brought in for determination (Bates 7557). This unicate was an eye-opener, particularly because, unlike the top-snatched Kral material, it had an intact rootstock containing a dense fascicle of small, fusiform, sweet-potato-like tubers, different from those produced by other known hydrophyllums. This feature, when combined with other less evident, but