Sporobolus pinetorum Weakley & P.M. Peterson. Phen: Jun-Sep (-Dec, in response to growing-season fire). Hab: Wet pine savannas, pine savanna-pocosin ecotones, longleaf pine sandhill-pocosin ecotones, and extending upslope into mesic pine flatwoods or loamy or clayey shelves in the fall-line Sandhills. Dist: Endemic to NC, SC, and e. GA.
Origin/Endemic status: Endemic
Taxonomy Comments: The identity of this taxon has been obscure; it is now clear that it is a previously unrecognized species, endemic to NC, SC, and adjacent e. GA. RAB included it in their concept of S. teretifolius, though it does not key well (keying imperfectly to either S. floridanus or S. heterolepis); in S and HC, it will key to S. floridanus, but the leaves are much narrower. Additionally, S. floridanus is a taller and coarser plant, the culms often averaging about 1.5 meters in height and 2-3 mm in diameter basally (vs. 1 meter high and 1 mm in diameter for S. pinetorum). In wet savannas of Columbus County, NC, S. pinetorum occurs with true S. teretifolius (the two codominant over many hectares!), and the two taxa are manifestly distinct. The leaves of S. pinetorum are not terete; after lengthy drought in the field (or dry on an herbarium sheet), the leaves become tightly folded to involute and can appear wiry.
Other Comments: Like many Southeastern pineland grasses, S. pinetorum flowers only following fire. In vegetative condition it may be distinguished from Aristida stricta and A. beyrichiana, with which it often grows, by the leaf pubescence (S. pinetorum with scaberulous margins, best felt by running a finger along the margin near the base, from apex toward base, A. stricta and A. beyrichiana not scaberulous, and with a sparse line of pilose hairs running more or less the length of the leaf in A. stricta and sometimes in A. beyrichiana) and base (much more indurated and polished in Sporobolus than in Aristida).
Synonymy: = FNA25, K1, K3, K4, Orzell & Bridges (2022), Weakley & Peterson (1998); < Sporobolus floridanus Chapm. – HC, S; > Sporobolus floridanus Chapm. – RAB, misapplied; >< Sporobolus teretifolius R.M.Harper – RAB, misapplied