Studies in the vascular flora of the Southeastern United States. XI.
DOI:
https://doi.org/10.17348/jbrit.v20.i3.1483Abstract
Hexastylis viridistylis (Aristolochiaceae) is described as a novel species distinguished from other species in the genus by a unique combination of morphological characters including style and ovary color and dimensions, stamen morphology, calyx tube dimensions, and fruiting characteristics. The range, habitat, phenology, and potential affinities to other species in the group are discussed in detail. We propose treating a number of taxa at species rank, elevating them from infraspecific ranks, to appropriately recognize their degree of isolation and distinctiveness compared to their relatives: Chrysopsis dressii (Semple) Weakley & S.G. Ward, Echinacea neglecta (McGregor) Weakley & A.P. Campos, Echinacea strigosa (McGregor) Weakley & A.P. Campos, Phacelia lundelliana (Constance) E.L. Keith & Weakley, and Houstonia glabra (Terrell) Weakley & D.B. Poind. In Dioscorea, we reassess a long-ongoing controversy regarding whether to recognize two or three native species, and clarify the distinctions between and distributions of Dioscorea villosa and D. quaternata, recognizing them at species rank, in addition to the uncontroversial D. floridana. In Sideroxylon sect. Frigoricola, we propose that the taxon named by J.K. Small as Bumelia lacuum does warrant taxonomic recognition as an entity separate from Sideroxylon tenax, but that the evidence suggests incomplete evolutionary separation of the two, and we therefore provide a name at varietal rank, Sideroxylon tenax var. lacuum (Small) S.G. Ward & Weakley and discuss its differentiation from var. tenax. Important distributional records (including additions, subtractions, clarifications, and other notable records) are made for the State of South Carolina and the Commonwealth of Virginia.
References
Ahles, H.E. 1968. Dioscoreaceae. In: A.E. Radford, H.E. Ahles, & C.R. Bell. Manual of the vascular flora of the Carolinas. UNC Press, Chapel Hill, U.S.A. Pp. 317–318.
Al-Shehbaz, I.A. & B.G. Schubert. 1989. The Dioscoreaceae in the southeastern United States. J. Arnold Arbor. 70:57–95.
Binns, S.E., B.R. Baum, & J.T. Arnason. 2002. A taxonomic revision of Echinacea (Asteraceae: Heliantheae). Syst. Bot. 27:610–632.
Blomquist, H.L. 1957. A revision of Hexastylis of North America. Brittonia 8:255–281.
Braun, E.L. 1967. The Monocotyledoneae. Cat-tails to orchids. Ohio State Univ. Press, Columbus, U.S.A.
Bridges, E.L. & S.L. Orzell. 2024. Systematics of the unifoliolate Floridian Lupinus clade (Leguminosae: Papilionoideae). Phytoneuron 2024-4:1–61.
Chester, E.W., B.E. Wofford, R. Kral, H.R. DeSelm, & A.M. Evans. 1993. Atlas of Tennessee Vascular Plants. Vol. 1, Pteridophytes, Gymnosperms, Monocots. Center for Field Biology, Austin Peay State Univ., Clarksville, U.S.A.
Constance, L. 1949. A revision of Phacelia subgenus Cosmanthus (Hydrophyllaceae). Contr. Gray Herb. 168:1–48.
Corogin, P.T. 2015. Sideroxylon Section Frigoricola (Sapotaceae): a clade endemic to temperate North America. Ph.D. dissertation, Univ. of Florida, Gainesville, U.S.A.
Deam, C.C. 1940. Flora of Indiana. Burford Printing Co., Indianapolis, U.S.A.
DeLaney, K.R., R.P. Wunderlin, & J.C. Semple. 2003. Chrysopsis delaneyi (Asteraceae, Astereae), another new species from peninsular Florida. Bot. Explorer 3:1–40.
Fernald, M.L. 1950. Gray’s manual of botany. Eighth Edition. American Book Co., Boston, U.S.A.
Flora of North America Editorial Committee, eds. 1993+. Flora of North America North of Mexico [Online]. 25+ vols. New York and Oxford. http://beta.floranorthamerica.org. Accessed 01 September 2025.
Foster, S. 1991. Echinacea: nature’s immune enhancer. Healing Arts Press, Rochester, U.S.A. 150 pp.
Freeman, C.C. 2019. Leucospora. In: Flora of North America Editorial Committee. 2019. Flora of North America north of Mexico. Volume 17, Magnoliophyta: Tetrachondraceae to Orobanchaceae. Oxford Univ. Press, New York, U.S.A. 737 pp.
Gaddy, L.L. 1987. A review of the taxonomy and biogeography of Hexastylis (Aristolochiaceae). Castanea 52:186–196.
Gentry, J.L., G.P. Johnson, B.T. Baker, C.T. Witsell, & J.D. Ogle. 2013. Atlas of the vascular plants of Arkansas. Univ. Arkansas, Fayetteville, U.S.A.
Gleason, H.A. 1952. The new Britton and Brown illustrated flora of the northeastern United States and adjacent Canada. New York Botanical Garden, New York, U.S.A.
Glennon, K.L. & S.A. Church. 2015. Gene flow contributes to genetic diversity of tetraploid populations of the North American plant genus Houstonia (Rubiaceae). Rhodora 117:41–66.
Haines, A.A. 2025. The variety of northern Houstonia longifolia (Rubiaceae). Bot. Notes 19:3–5.
Hill, S.R. 1999. The relict flora of ice ponds in South Carolina. Castanea 64:14–22.
Huck, R.B. 2001. Two new infraspecific taxa in Florida Dicerandra (Labiatae). Novon 11:417–420.
iNaturalist. 2025. Available from https://www.inaturalist.org. Accessed 01 September 2025.
Kartesz, J.T. 2015. The Biota of North America Program (BONAP). Biota of North America, Chapel Hill, U.S.A. www.bonap. net.
Kees, J.C., A.S. Weakley, & D.B. Poindexter. 2024. Towards a revision of the Eryngium integrifolium complex (Apiaceae). Phytoneuron 2024-70:1–25.
Keller, H.W. 2014. The genus Echinacea (Asteraceae): floral, stem, and petiole morphology. J. Bot. Res. Inst. Texas 8:87–126.
Lakela, O. 1963. The identity of Bumelia lacuum Small. Rhodora 65:280–282.
MacRoberts, D.T. 1984. The vascular plants of Louisiana. Bull. Mus. Life Sci. Louisiana State Univ., Shreveport 6:1–165.
McClelland, R.K.S., A.S. Weakley, & D.B. Poindexter. 2023. Seven new species of Trichostema (Lamiaceae: Ajugoideae) from the North American Coastal Plain biodiversity hotspot. Phytotaxa 603:95–149. doi:10.11646/phytotaxa.603.2.1
McGregor, R.L. 1967. A new species and two new varieties of Echinacea (Compositae). Trans. Kansas Acad. Sci. 70:366–370.
McGregor, R.L. 1968. The taxonomy of the genus Echinacea (Compositae). Univ. Kansas Sci. Bull. 48:113–142.
McKeown, K. 1999. A review of the taxonomy of the genus Echinacea. In: J. Janick (ed.). Perspectives on new crops and new uses. ASHS Press, Alexandria, VA. https://api.semanticscholar.org/CorpusID:2095281. Accessed 21 March 2026.
Mohlenbrock, R.H. & D.M. Ladd. 1978. Distribution of Illinois Vascular Plants. Southern Illinois Univ. Press, Carbondale, U.S.A.
Mosyakin, S.L. 2005. Rumex. In: Flora of North America Editorial Committee. 2005. Flora of North America north of Mexico. Volume 5, Magnoliophyta: Caryophyllidae, part 2. Oxford Univ. Press, New York, U.S.A. 656 pp.
NatureServe. 2025. NatureServe Network Biodiversity Location Data accessed through NatureServe Explorer NatureServe, Arlington, Virginia. Available https://explorer.natureserve.org/. Accessed 12 September 2025.
Padgett, J.E. 2004. Biogeographical, ecological, morphological, and micromorphological analyses of the species in the Hexastylis heterophylla complex. Master’s Thesis, Appalachian State Univ., Boone, North Carolina, U.S.A. 125 pp.
Poindexter, D.B., L. Anderson-Messec, J.B. Fuller, B. Dellinger, E.A. Ungberg, & A.S. Weakley. 2024. Discovery of disjunct populations of the federally threatened Golden Sedge (Carex lutea, Sect. Ceratocystis) and first reported chromosome counts of the species, aided by social media and iNaturalist. In: Weakley et al. 2024. Studies in the vascular flora of the southeastern United States. X. J. Bot. Res. Inst. Texas 18:17–77.
Rader, E.K. & N.H. Evans. 1993. Geologic map of Virginia; expanded explanation: Virginia Division of Mineral Resources, U.S.A. 80 pp.
Radford, A.E., H.E. Ahles, & C.R. Bell. 1968. Manual of the vascular flora of the Carolinas. Univ. of North Carolina Press, Chapel Hill, U.S.A.
Raz, L. 2002. Dioscoreaceae. In Flora of North America, vol. 26, Magnoliophyta: Liliidae: Liliales and Orchidales. Oxford Univ. Press, New York, U.S.A.
Semple, J.C. 1978. Application of the name Chrysopsis hyssopifolia Nutt. (Compositae) and a new name for an “old” species. Brittonia 30:492–495.
Semple, J.C. 1981. A revision of the goldenaster genus Chrysopsis (Nutt.) Ell. nom. cons. (Compositae–Astereae). Rhodora 83:323–384.
Semple, J.C. 2006. Chrysopsis. In: Flora of North America Editorial Committee. 2006b. Flora of North America north of Mexico. Volume 20, Magnoliophyta: Asteridae, part 6: Asteraceae, part 2. Oxford Univ. Press, New York, U.S.A. 666 pp.
Semple, J.C. 2025. Chrysopsis. Astereae lab website. https://uwaterloo.ca/astereae-lab/goldenasters/chrysopsis. Accessed 07 September 2025.
Semple, J.C. & J.B. Beck. 2021. Revised infrageneric classification of Solidago (Asteraceae: Astereae). Phytoneuron 2021- 10:1–6. Published 26 Feb 2021.
Semple, J.C. & J.B. Beck. 2023. A revised intuitive phylogeny of Solidago (Asteraceae: Astereae) based on a polygenomic phylogeny of diploids. Phytoneuron 2023-41:1–5. Published 31 October 2023.
Semple, J.C., H. McMinn-Sauder, M. Stover, A.R. Lemmon, E. Moriarty Lemmon, & J.B. Beck. 2023. Goldenrod herbariomics: Hybrid-sequence capture reveals the phylogeny of Solidago. Amer. J. Bot. doi: 10.1002/ajb2.16164
Semple, J.C. & N. Steenhof. 2025. A multivariate morphometric study of the Chrysopsis scabrella complex (Asteraceae: Astereae). Phytoneuron 2025-05:1–13. Published 30 April 2025.
SERNEC Data Portal. 2025. http://sernecportal.org/index.php. Accessed on 01 September 2025.
Sinn, B.T. 2015. Asarum chueyi (Aristolochiaceae), a new species from the foothills of the Blue Ridge Mountains of Tennessee and Virginia, U.S.A. Phytotaxa 224:85–95.
Skibicki, S.V. 2025. Phylogenomics and biogeography of Zinniinae (Asteraceae: Heliantheae) using plastome and nuclear datasets. Ph.D. dissertation, West Virginia Univ., Morgantown, U.S.A. Graduate Theses, Dissertations, and Problem Reports. https://researchrepository.wvu.edu/etd/12835
Small, J.K. 1933. Manual of the southeastern flora. Univ. of North Carolina Press, Chapel Hill, U.S.A.
Smith, E.B. 1976. Hedyotis ouachitana (Rubiaceae): a new species from the Ouachita Mountains of Arkansas and Oklahoma. Brittonia 28:453–459.
Smith, E.B. 1978. An atlas and annotated list of the vascular plants of Arkansas. Univ. of Arkansas Herbarium, Fayetteville, U.S.A.
Sorrie, B.A. 1998. Distribution of Drosera filiformis and D. tracyi (Droseraceae): Phytogeographic implications. Rhodora 100:239–260.
Sorrie, B.A. 2018. Solidago aestivalis in the Carolinas. In: Weakley, A.S., D.B. Poindexter, R.J. LeBlond, B.A. Sorrie, E.L. Bridges, S.L. Orzell, A.R. Franck, M. Schori, B.R. Keener, A.R. Diamond, Jr., A.J. Floden, & R.D. Noyes. 2018. New combinations, rank changes, and nomenclatural and taxonomic comments in the vascular flora of the southeastern United States. III. J. Bot. Res. Inst. Texas 12:27–67.
Sorrie, B.A. & A.S. Weakley. 2001. Coastal plain vascular plant endemics: phytogeographic patterns. Castanea 66:50–82.
Steyermark, J.A. 1963. Flora of Missouri. Iowa State Univ. Press, Ames, U.S.A.
Strong, J. & J. McClintock. 1880. The cyclopedia of biblical, theological, and ecclesiastical literature. Harper and Brothers, New York, U.S.A.
Tennessee Flora Committee. 2015. Guide to the vascular plants of Tennessee, E.W. Chester, B.E. Wofford, J. Shaw, D. Estes, and D.H. Webb, eds. Univ. Tennessee Press, Knoxville, Tennessee, U.S.A.
Terrell, E.E. 1959. A revision of the Houstonia purpurea group (Rubiaceae). Rhodora 61:157–181, 188–207.
Terrell, E.E. 1988. Nomenclatural notes on Houstonia (Rubiaceae). Phytologia 65:119–121.
Terrell, E.E. 1996. Revision of Houstonia (Rubiaceae-Hedyotidae). Syst. Bot. Monogr. 48:1–118.
Thomas, J.R. 2017. New additions, vouchers of old additions, and a new combination (Dichanthelium inflatum) for the Missouri flora. Missouriensis 34:4–19.
Urbatsch, L.E., K.M. Neubig, & P.B. Cox. 2006. Echinacea. In: Flora of North America Editorial Committee. 2006. Flora of North America north of Mexico. Volume 21, Magnoliophyta: Asteridae, part 6: Asteraceae, part 3. Oxford Univ. Press, New York, U.S.A. 616 pp.
Uttal, L.J. & D.M. Porter. 1988. The correct name for Elliott’s goldenrod. Rhodora 90:157–168.
Voss, E.G. 1972. Michigan flora. Part 1, Gymnosperms and Monocots. Cranbrook Inst. of Sci. and Univ. Michigan Herbarium, Bloomfield Hills, U.S.A.
Voss, E.G. & A.A. Reznicek. 2012. Field manual of Michigan flora. Univ. of Michigan Press, Ann Arbor, U.S.A.
Ward, D.B. 2007. Thomas Walter Typification Project, II: The known Walter types. J. Bot. Res. Inst. Texas 1:407–423.
Watson, L.E. 2006. Marshallia. In: Flora of North America Editorial Committee. 2006. Flora of North America north of Mexico. Volume 21, Magnoliophyta: Asteridae, part 6: Asteraceae, part 3. Oxford Univ. Press, New York, U.S.A. 616 pp.
Weakley, A.S. & P.M. Peterson. 1998. Taxonomy of the Sporobolus floridanus complex (Poaceae: Sporobolinae). Sida 18:247–270.
Weakley, A.S., J.C. Kees, B.A. Sorrie, S.G. Ward, D.B. Poindexter, M. Brock, L.D. Estes, E.L. Bridges, S.L. Orzell, G.A. Levin, R.K.S. McClelland, R.J. Schmidt, & S.A. Namestnik. 2023. Studies in the vascular flora of the southeastern United States. IX. J. Bot. Res. Inst. Texas 17:191–257.
Weakley, A.S., R.J. LeBlond, P.D. McMillan, B.A. Sorrie, D.B. Poindexter, J.B. Fuller, E.L. Bridges, B.J. Budach, S.C. Carr, A.A. Crowl, P. Manos, P.W. Fritsch, S.L. Orzell, J.K. Wipff, L. Anderson Messec, B. Dellinger, E.A. Ungberg, N.D. Yawn, A.M. Cressler, T.W. Barger, J. R. Carter, A.J. Floden, W.M. Knapp, I. Copen, A.M. Jenkins, E.L. Hughes, J. Annis, W. Baker, & R.L. Mears. 2024. Studies in the vascular flora of the southeastern United States. X. J. Bot. Res. Inst. Texas 18:17–77.
Weakley, A.S. & Southeastern Flora Team. 2025. Flora of the southeastern United States Web App. Univ. of North Carolina Herbarium, North Carolina Botanical Garden, Chapel Hill, U.S.A. fsus.ncbg.unc.edu. Accessed 12 September 2025.
Werier, D. 2017. Catalogue of the vascular plants of New York state. Mem. Torrey Bot. Soc. 27.
Yatskievych, G. 1999. Steyermark’s flora of Missouri. Volume 1. Missouri Bot. Garden Press, St. Louis, U.S.A.
Zhang, N., D.L. Erickson, P. Ramachandran, A.R. Ottesen, R.E. Timme, V.A. Funk, Y. Luo, & S.M. Handy. 2017. An analysis of Echinacea chloroplast genomes: implications for future botanical identification. Scientific Reports 7:216.
Downloads
Published
How to Cite
Issue
Section
License
Copyright (c) 2026 Journal of the Botanical Research Institute of Texas
This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.
