76 Phytologia (April2009) 91(1) TAXONOMY OFIVA ANGUSTIFOLIA AND ASPERIFOLIA /. (ASTERACEAE) B. L. Turner Plant Resources Center The University ofTexas at Austin Austin, Texas 78712 [email protected] ABSTRACT Iva angustifoUa and /. asperifoUa are treated as belonging to a single species, /. asperifoUa. The species is treated as having three varieties: var. angustifoUa, widespread in the south-central U.S.A.; var. latior, largely confined to the beaches of southern Texas; and var. asperifoUa, confined to the coastlines of central Mexico, with an introduced outlier in Wakulla Co., Florida. Keys to the taxa are provided, along with maps showing theirdistribution. Phytologia 91(1):76-83 (April, 2009). KEY WORDS: Asteraceae,IvaangustifoUa, I. asperifoUa, I. texensis, Texas, Mexico, Florida Strother (2006), in his treatment oiIva for the Flora ofNorth America, provided a taxonomic account of/. angustifoUa Nutt. ex DC. In this he did not provide for infraspecific categories, nor did he discuss its relationship to its closest congener, /. asperifoUa, a taxon from dune sands along the Gulf Coast of Mexico. He did place in synonymy under his broad interpretation of /. angustifoUa the names /. a. var. latior Shinners and /. texensis R.C. Jackson, both typified by material from sandy orclay saline dunes ofsouthernmost coastal Texas. Jackson (1960) proposed the name Iva texensis (typified by Jackson 2505 from saline soils ca. 8 mi S of Falfurrias, Brooks Co., Texas). Oddly, other than the type, he listed numerous additional collections, these introduced with the statement that "A number of specimens from the coastal regions ofTexas are tentatively assigned to Phytologia (April2009) 91(1) 11 I. texensis. These plants have a woody stem, but in involucral length and plant height are not always in agreement with the type." Shinners (1964) inexplicably described again Jackson's Iva texensis with his proposal of/. angustifolia var. latior, the latter also typified by specimens from Brooks Co., Texas. Indeed, Shinners did not mention /. texensis in his account ofthe proposed variety, although he did cite Jackson's revision of Iva in which the name was first proposed. Strother's account of Iva angustifolia for the U.S.A. is confounded by the earliername, /. asperifolia Lessing, this proposed in 1830. Strother did comment upon the latter, noting in the introduction to his treatment, that "Records ofIva asperifolia Lessing from Florida are evidently based on specimens that are treated as members of /. angustifolia.'''' A similar sentiment was expressed by Wunderlin (1998) who thought the name /. asperifolia, was "misapplied" to plants from Wakulla Co. Florida, that he took to be /. angustifolia. This, in spite of the fact that Jackson (1960) stated, "The specimens of/, asperifolia from Florida may represent an introduction [of A. asperifolia] from Mexico." Plants grown from seeds by Jackson in his greenhouse (the seeds provided by Dr. R. K. Godfrey from Wakulla Co.) reportedly "gave plants with procumbent terms (sic)." Jackson further noted that the Mexican plants, which he observed along the beaches ofVeracruz, Mexico, were similarly decumbent perennials that root at the nodes. One must assume that Jackson knew what he was talking about, hence the comments ofClewell (1985), no doubt bowing to the judgment of Jackson to the effect that the Wakulla populations, which he took to be /. asperifolia, are "decumbent perennials rooting at the nodes;" Clewell ftirther noted that the plants occur in tidal marshland and were "Probably introduced from Mexico." I have also examined collections from the Florida populations concerned and they appear to be closer in habitto/. asperifoliathan to/. angustifolia, as notedby Jackson. Miao, Turner and Mabry (1995) examined chloroplast DNA variation in all species of Iva, except for the mostly Cuban, /. cheiranthifolia. Their study included all four species of sect. Linearibractea R.C. Jackson, which included /. angustifolia, I. asperifolia, I. texensis, and /. microcephala. Indeed, in their sequence divergence study the four species ofsect. Linearibractea formed a tight 78 Phytologia (April2009) 91(I) cluster, the most distinct being /. microcephala, which was found to be the most divergent member of the tetrad. The remaining three taxa were found to have few differences among them. In particular, the two herbaceous taxa, /. angustifoUa and /. asperifoUa, were found to differ DNA by only one restriction site mutation. Unfortunately, data for /. asperifoUa was obtained from the Wakulla Co. population, which Jackson accepted as an introduction from the Mexican beaches. The taxonomic status ofthe latterpopulation is controversial, as noted in the above. Considering the Pleistocene history ofthe southeastern U.S.A., it is possible that the Wakulla population is but an isolated relic of a once more widespread, highly variable, var. angustifoUa, perhaps deserving of its own formal varietal name. Additional study of the /. asperifoUa complex is clearly needed, especially from Tamaulipas where the two taxapresumably intergrade. With the above as an introduction, I hasten to add that I also (Turner et al. 2003) recognized Texas populations ofthe /. asperifoUa complex as /. angustifoUa, largely following the work of Jackson. Unlike Strother, I did recognize the more robust, seemingly perennial, var. latior of Shinners, with the assumption that it intergraded northwards along the shores ofTexas into the typical var. angustifoUa, as also noted by Jackson. I also believe that the var. latior intergrades southwards along the Gulfbeaches ofMexico into var. asperifoUa. This suggested by a single intermediate, cited below. I provide herein a synopsis of the /. asperifoUa complex as currently understood, along with a nomenclature that appears to fit the biology. IVA ASPERIFOUA Lessing, Linnaea 5: 151. 1830. TYPE: MEXICO. VERACRUZ: Mpio. Veracruz, "Inpascuis pr. Vera-Cruz."Jul. Scheide 332 (holotype B; fragment and drawing, GH). Jackson (1960) providedadetaileddescription ofthe taxon, positioning it in his sect. Linearbractea. Phytologia (April2009) 91(1) 79 Key to infraspecific taxa: m 1.Plants annuals mostly 0.75 high or less; south-central U.S.A. (Kan., Okla., Tex., Ark., La.) var. angustifolia m 1.Plants perennial herbs to 1.5 high; GulfCoastal dunes, southernmost Texas, northern Mexico and panhandle Florida (2) 2.Stems decumbent, rooting at the nodes; leaves mostly oblong- lanceolate; involucres without markedly spreading, broad-based hairs; coastal Tamaulipas andVeracruz, Mexico var. asperifolia 2.Stems stiffly erect, only rarely rooting at the nodes; leaves mostly lanceolate; involucres with markedly broad-based spreadinghairs, rarely not; northern coastal Tamaulipas, Mexico, and southern Texas var. latior IVA ASPERIFOLIA var ANGUSTIFOLIA (Nutt. ex DC.) B.L Turner, stat. & comb. nov. Fig. 1 BaseduponIvaangustifolia Nutt. ex DC, Prodr. 5: 529. 1836. TYPE: U.S.A. ARKANSAS: without locality, Nuttalls.n. (holotype: G-DC; isotype NY) Jackson (1960) provided an adequate account of this taxon, noting in his key the principal differences that distinguish it from var. latior, the latterbeing larger, mostly perennial, plants having somewhat larger involucres, the latter well endowed with spreading hairs. In my opinion, var. angustifolia grades into var. latior in regions of near contact, as noted below, hence their treatment as but populational variants (orvariety) ofa widespreadIvaasperifolia. Varity angustifolia is highly variable and, other than habit, is best recognized by a suite of characters, most having to do with the involucre, as notedbelow andbyJackson (1960). IVA ASPERIFOLIA Lessing var. ASPERIFOLIA Fig. 1, 2 As noted in Figures 1 and 2 (based upon specimens at MEXU, TEX), this taxon is restricted to the Gulf Coastal area of northern Tamaulipas and Veracruz, Mexico, with an isolated population in 80 Phytologia (April2009) 91(1) Wakulla Co., Florida. In Tamaulipas, Mexico, it seemingly grades into the var. latior, tojudge from the following collection: Mpio. Altamira, Dimas 856 (MEXU, TEX). The taxonomic status of the Florida populations of var. asperifolia is in doubt. According to label data on Godfrey 70060 (TEX), the Wakulla population occurs "On a large flat area into which spoils from dredging of the St. Marks River had been placed; very abundant; St. Marks." The DNA voucher of Miao et al. (1995) was obtained "In limestone piles of spoil, St. Marks, just west of end of county Road 363 and north of St. Marks River." Both of the aforementioned collections are seemingly perennial. The Godfrey collection has a capitulescence much resembling var. angustifolia; the Miao voucher (Garland 751, TEX) has an atypical capitulescence. Based on the DNA data from the latter voucher and the comments of Jackson (1960), it would appear that the Wakulla population is closest to var. asperifolia. Alternatively, it is remotely possible that the Wakulla populations represent a localized yet undescribed variety of/. asperifolia, as noted above. IVA ASPERIFOLIA var. LATIOR (Shinners) B L. Turner, comb, nov. Fig.1 Based uponIvaangustifolia var. latior Shinners, Sida 1: 378. 1964. TYPE: U.S.A. TEXAS: Brooks Co., "south ofFalfurrias." 15 Sep 1942,Limdell& Limdell 11947(holotype SMU; isotypes LL!) Iva texensis R.C. Jackson, Univ. Kansas Sci. Bull. 41: 807. 1960. TYPE: U.S.A. TEXAS: Brooks Co., 8.1 mi S ofFalfurrias along U.S. highway 281, 24 Aug 1957,Jackson 2505 (holotype KANU; isotype SMU) Jackson's Iva texensis was published prior to Shinner's var. latior, unfortunately nomenclatural priority is predicated upon rank; were the present taxon recognized as a species, its correct name would be/, texensisl m Variety latior is a perennial herb to 1.5 high, largely confined to the GulfCoastal region ofTexas, mostly occurring in sandy Phytologia (April2009) 91(1) or clay dunes along the beach front; numerous collections are in the herbarium at TEX (35 from along the coastal areas of Cameron, Kenedy and Nueces counties). The earliest collections of var. latior were made by Robert Runyon in Cameron County between the years 1924-1945 (TEX, LL). He noted that the taxon was sufficiently well known as to have received the local common name "Pelocote." And that the taxon occurs "only along sea shore as colonies on sand dunes;" and describes its habit as an "erect branched herb," or "fruticose herb." Nevertheless, it also occurs sporadically inland into the Tamaulipan Biotic Province of southern Texas, as indicated in Fig. 1. Occasional intergrades between var. latior and var. angnstifolia in this area are discerned (e.g., Carr 22574, Refugio Co., TEX). The more strictly coastal populations ofvar. latior pass into var. angustifolia near Galveston, Texas, the latter becoming m strictly taprooted annual herbs mostly 0.5 high or less, having smaller involucres with mostly shorterappressedhairs. As suggested by its dune-site proclivities in Kenedy and Cameron counties, it is almost certain that southwards var. latiorgrades into var. asperifolia, as suggested by the intermediate specimen cited above. Even among the Texas coastal populations, some degree ofpast introgression is likely, to judge from the variation in leaf shape and pubescence noted among the Cameron countypopulations. ACKNOWLEDGEMENTS I am grateful to my colleagues, Guy Nesom and John Strother for reviewing the paper and providing helpful comments. Thanks also MEXU to for the loan ofspecimens, these critical in the construction of distribution maps forIvaasperifolia var. asperifolia. LITERATURE CITED Clewell, A.F. 1985. Guide to the VascularPlants ofthe Florida Panhandle. Florida State Univ. Press, Tallahassee Jackson, R.C. 1960. Arevision ofthegenusIva L. Univ. Kansas Sci. Bull. 41:793-875. 82 Phytologia (April2009) 91(1) Miao, B., B.L. Turnerand T.J. Mabry. 1995. Molecularphylogeny of DNA Iva (Asteraceae, Heliantheae) basedon chloroplast restriction site variation. PI. Syst. Evol. 195: 1-12. Strother, J.L. 2006. Iva, in Fl. N. Amer. (N. ofMexico.) 21: 25-28. Turner, B.L., H. Nichols, G. Denny and O. Doron. 2003. Atlas ofthe VascularPlants ofTexas 1: 1-648. Wunderlin, R.P. 1998. Guide to the VascularPlants ofFlorida. Univ. Press, Florida Fig.l. Distribution by county (andparish) ofIvaasperifolia in the U.S.A. Phytologia (April2009) 91(1) 83 Fig. 2. Distribution oilvaasperifolia in Mexico.