Species and wiregrass
On a recent outing with a group led by likely an eminent SE US plant systematist, I was told in no uncertain terms that Aristida stricta is endemic to the Carolinas and is not found in Florida. This came as a great shock to me. I once lived in pine flatwoods in Palm Beach County Florida. I IDed as many plants as I could, including Aristida stricta, which seemingly grew everywhere in Florida pinelands. I bided my time, though. I would be a fool to argue plant systematics with Alan Weakley (one of the incredibly well-respected luminaries in the constellation of plant scientists at UNC, while I have no bona fides), especially in a group of people that had better things to hear.
So I went home and poked around. iNaturalist has Aristida stricta observations in Florida. But I noted that almost none were research grade.
In Flora of the Southeastern United States, Edition of April 24, 2022, the Aristida key splits into A. stricta and A. beyrichiana, placing the former in North and northern South Carolina and the latter in south and west South Carolina, to south FL, and to south Mississippi.
iNaturalist has many more A. beyrichiana observations in Florida, about half of which were tagged as research grade. The really good observations capture the keying attributes defined by Peet.
Robert Peet (another all-star in the same constellation in which one finds Weakley) split beyrichiana from stricta based on some morphological differences (differences in leaf sheath pubescence) and the fact there is a gap in South Carolina that separates stricta and beyrichiana populations (geographic separation).
Peet, Robert K. “A TAXONOMIC STUDY OF ARISTIDA STRICTA AND A. BEYRICHIANA.” Rhodora, vol. 95, no. 881, 1993, pp. 25–37. JSTOR, http://www.jstor.org/stable/23314723. Accessed 23 Jan. 2024.
Even for a non-botanist like me, Peet's paper is a very readable (https://www.biodiversitylibrary.org/partpdf/123283). He makes a strong argument for the separation of the two species, including the durability through time of the observed gap in geography.
Counter to Peet, Kesler et al found that the morphological differences may not hold strongly and that when more extensive morphology sampling and allozyme data are combined a separation at the species level is not warranted.
Tina R. Kesler, Loran C. Anderson, and Sharon M. Hermann "A TAXONOMIC REEVALUATION OF ARISTIDA STRICTA (POACEAE) USING ANATOMY AND MORPHOLOGY," Southeastern Naturalist 2(1), 1-10, (1 March 2003). https://doi.org/10.1656/1528-7092(2003)002[0001:ATROAS]2.0.CO;2
Sharma et al, following Kesler and lumping to a single species, emphasized differences among NC, SC, GA, FL, AL, and MS populations. The authors include a dendrogram that shows affinity between NC and SC populations, but also clustered these Carolina populations with populations from some Florida sample locations (Peet's paper also identified some closer correspondence between some Florida specimens and his delimited A. stricta). These Florida populations clustered more closely with the Carolina populations than they did with population data from other locations. The authors' finding emphasized within population coherence for underscoring the need to use local plant and seed sources for restoration to maintain diversity across population, which is often the point of delimitations.
Sharma J, George S, Pandey M, Norcini J, Perez H. Genetic differentiation in natural populations of a keystone bunchgrass (Aristida stricta) across its native range. Genetica. 2011 Feb;139(2):261-71. doi: 10.1007/s10709-010-9545-x. Epub 2011 Jan 12. PMID: 21225317.
Shearman et al nominally maintained the two species but lumped their species data as "wiregrass", effectively treating the two as a pool of populations rather than of species.
Allometry of the pyrophytic Aristida in fire-maintained longleaf pine–wiregrass ecosystems
Timothy M. Shearman, J. Morgan Varner, Kevin Robertson, J. Kevin Hiers https://doi.org/10.1002/ajb2.1215
Related to this specific instance of splitting a species is the notion of "species concepts", which are many. Scientific American has a nice blog entry on the subject: https://blogs.scientificamerican.com/evo-eco-lab/species-concepts/. An attempt to unify multiple species concepts is at https://academic.oup.com/sysbio/article/56/6/879/1653163.
The Google has decided that these species concepts are most probable for searching (as predicted in a search bar to extend "species concept "): phylogenetic, morphological, biological, ecological, evolutionary, typological.
An integration of concepts is described by Benoit Dayrat in https://onlinelibrary.wiley.com/doi/10.1111/j.1095-8312.2005.00503.x. In a tour de force, this approach is applied in practice by Bridges and Orzell to delimit new species of lupines in the Florida unifoliate group, using genetic, geographical, ecological, and morphological data: https://www.phytoneuron.net/wp-content/uploads/2024/01/04-PhytoN-UnifoliolateLupinus.pdf.
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