Galium concinnum Torr. & A. Gray

Galium concinnum Torr. & A. Gray View in CoL ( Rubiaceae ). MISSISSIPPI: Jasper Co.: J.C. Kees 1262 (NCU). This is the first report of G. concinnum for Mississippi and the East Gulf Coastal Plain floristic province, approximately 300 miles distant from the nearest records east of the Mississippi River, in the Interior Low Plateau of Williamson County, Tennessee. It is one of many northern disjuncts associated with Oligocene-age limestone outcrops which occur scattered across central, MS from Rankin County eastward, separated from the Jackson Prairie by the generally acidic and sandy Forest Hill formation. The species is locally abundant on steep limestone bluffs east of Tallahalla Creek in Jasper County, including lower-quality cutover sites and roadsides, but was not observed at any other known systems of Oligocene limestone bluffs in MS during field surveys.

Matelea baldwyniana (Sweet) Woodson ( Apocynaceae ). MISSISSIPPI: Wayne Co.: J.C. Kees 1344 (NCU). Matelea baldwiniana was erroneously attributed to Mississippi by Kartesz (2015), there are no vouchers or occurrence records (MSNHP 2021) of the species from MS and suitable habitat is not known from either county reported. This is the first verified report from the state. Populations also occur in limestone forests of the coastal plain of Alabama and Florida, disjunct from a primary distribution in the Ozarks and Ouachitas of Arkansas and adjacent Oklahoma and Missouri.In Wayne County, MS, M. baldwyniana occurs in dry Quercus muehlenbergii — dominated woodlands at the crest of several steep Oligocene limestone bluffs and bordering limestone barrens. These communities are closely related geologically and floristically to the submesic limestone forests of the Lime Hills region of Alabama where the species has been previously documented. All occurrences documented in Mississippi are on unprotected land and threatened by timber management.

Mirabilis albida (Walter) Heimerl ( Nyctaginaceae ). MISSISSIPPI:Lowndes Co.: J.C.Kees 1436 (NCU).Vouchers of this species from chalk prairies in the Black Belt of Mississippi appear to represent Mirabilis linearis . Mirabilis albida has been previously reported from “sandy fields” in Noxubee County (A.G. Marler s.n., MISS) and the “Chitlin Corners” area of Lowndes County ( Holmes & Amor 2010), but apparently not observed in the state since 1976. A few plants were located during a brief survey of sand barrens of Chitlin Corners, restricted to a single relatively undisturbed xeric opening on Corps of Engineers property along the Tennessee-Tombigbee Waterway. Development along the waterway and growth of a dense, fire-suppressed midstory has eliminated most of the former open woodland and barrens in the area. Natural open sand barrens over alluvial deposits, apparently maintained by deep, xeric, sandy soils even in the absence of fire, occur along the Tombigbee River from Monroe County southeast into Alabama, and continue to yield new reports of rare and disjunct species. While sand barren-like vegetation has developed over some Corps of Engineers dredge deposits (some of which have replaced natural sand barrens) and sandy old fields in the area, many of the rarer species associated with this undescribed community, such as Mirabilis albida , Astragalus distortus , Sida elliottii , and Callirhoe triangulata are known only from natural and relatively undisturbed xeric openings or roadsides through nearby woodlands. Soil disturbance from past grazing and clearing for wildlife food plots has degraded most remaining sand barrens, and the construction of the Tennessee-Tombigbee waterway has eliminated natural flooding events which were likely involved in the formation of these barrens.