Pyxidanthera barbulata Michaux var. brevifolia (B.W. Wells) H.E. Ahles. Phen: Dec-Mar; Feb-May. Hab: On xeric sandhills, generally over deep sand, sand-clay mixtures, or plinthite, near the summits or on the upper slopes of sandhills, restricted to the Fall-line Sandhills region. Dist: This species is endemic to a six-county area of the Fall-line Sandhills of NC and SC. In NC, it is nearly limited to Fort Bragg, and is puzzlingly absent from seemingly suitable habitat on the Sandhills Game Land to the west.
Origin/Endemic status: Endemic
Taxonomy Comments: The taxonomic status of this entity has been controversial, with different authors considering it a species, a variety, or an ecotype not worthy of taxonomic status (see synonymy and references). A combination of morphologic, embryologic, phytogeographic, ecological, and phenologic evidence favors the recognition of two taxa in Pyxidanthera. Recent surveys of Pyxidanthera in the Sandhills of NC have shown that it is ecologically distributed in a strongly bimodal manner. While ecologically intermediate situations predominate in the Sandhills, this habitat is rarely occupied by Pyxidanthera. Instead, Pyxidanthera is usually found either in very dry (hill-top) or moist (pocosin ecotones) situations. A few morphologically intermediate populations are occasionally found, in ecologically intermediate situations, but the vast majority of populations are readily assigned to one taxon or the other. Godt & Hamrick (1995) showed low levels of allozyme differentiation between the two taxa and supported varietal status. Wall et al. (2010a) found a complicated genetic structure with poor differentiation between the two taxa. Varietal status seems warranted based on our current understanding. See Wall et al. (2010a, 2010b) for discussion of genetic differentiation and reproductive biology.
Synonymy: = RAB; = Pyxidanthera brevifolia Wells – FNA8, K1, K3, K4, S; < Pyxidanthera barbulata Michx. – Primack & Wyatt (1975), Scott & Day (1983)