A NEW SPECIES OF MARSHALLIA (ASTERACEAE, HELENIEAE, MARSHALLIINAE) FROM MAFIC WOODLANDS AND BARRENS OF NORTH CAROLINAAND VIRGINIA Alan S. Weakley & Deeick B. Poindexter UNC Herbarium (NCU) North Carolina Botanical Garden University of North Carolina Chapel Hill, North Carolina 27599-3280 weakley@unc.edu ABSTRACT A new species of Marshallia (Asteraceae, Helenieae, Marshalliinae) is proposed and contrasted with the morphologically most similar and putatively most closely related species, M grandiflora andM obovata. The new species is known from a few sites in the Piedmont of north- central North Carolina and south-central Virginia, occurring solely or primarily in remnants of fire- and edaphically maintained oak savannas, barrens, and "prairies" developed over cation-rich, shrink- swell clay soils derived from the mafic rocks diabase and greenstone. KEY WORDS: Marshallia legrandii, Marshallia obovata, Marshallia grandiflora, Asteraceae, Helenieae, North Carolina, Virginia. Georgia, Florida, southeastern United States, endemic, imperiled Marshallia Schreber is a small genus (7-11 taxa) endemic to the southeastern USA (interpreted broadly), with species extending as far north as southwestern Pennsylvania and as far west as southeastern Kansas, central Oklahoma, and central Texas. It has long been regarded as distinctive, enigmatic, and "strange" (Baldwin 2009), with contrasting assessments of its closest generic relatives and tribal placement. Beadle & Boynton (1901) published the first comprehensive account of the genus and established the foundation for an understanding of its component species, naming three species (each of them rare and local: M. grandiflora Beadle & Boynton, M. mohrii Beadle & Boynton, andM ramosa Beadle & Boynton) and recognizing a total of 11 taxa (7 species, with 4 additional varieties). Building on this, Channell (1957) monographed the genus, largely agreeing taxonomically with Beadle & Boynton (1901), recognizing 10 taxa (8 species, with 2 additional varieties), by elevating one of Beadle & Boynton 's (1901) varieties to specific rank (M tenuifblia) and dismissing another (M. grammifolia var. lacinarioides). In the half-century since Channell (1957), the most notable work on the genus has been by Linda Watson, James Estes, and collaborators, who published a series of publications in the early 1990s exploring the taxonomy of members of the genus and its tribal affinities (Watson & Estes 1990; Watson, Elisens, & Estes 1991; Watson, Jansen, & Estes 1991). Recent floristic works have generally followed the framework established by Channell (1957), with minor but significant diversity of opinion about the worth of recognition of some varieties or their taxonomic rank Cronquist (1980) followed Channell exactly (8 species, 2 additional varieties). In her Flora of North America treatment, Watson (2006) formally recognized 7 species, providing characters and distributions for three additional varieties, apparently considered them of uncertain or optional taxonomic value. A consensus list of taxa accepted in the genus in the early 21" century would include these: M. caespitosa Nutt. ex DC. var. caespitosa, M. caespitosa Nutt. ex DC. var. signata Beadle & Boynton, M. graminifolia (Walt.) Small, M. tenuifolia Raf, M. grandiflora Beadle & Boynton, M. mohrii Beadle & Boynton, M. obovata (Walt.) Beadle & Boynton var. obovata, M. obovata (Walt.) Beadle & Boynton var. scaposa Channell, M. ramosa Beadle & Boynton, andM. trinervia (Walt.) Trel. Weakley and Poindexter: New species of Marshallia 2 In 1986, North Carolina Natural Heritage Program biologist Harry E. LeGrand, Jr. found an unusual population of Marshallia near Butner, Granville County, North Carolina. This Marshallia was found in a dry, mafic barren over diabase in a site since dubbed the Picture Creek Diabase Barren (North Carolina Natural Heritage Program). LeGrand tentatively identified the Picture Creek Marshallia using existing floristic treatments (Radford, Ahles, & Bell 1968; Cronquist 1980) as M. grandiflora Beadle & Boynton, but noted that the identification was not definite or satisfying (North Carolina Natural Heritage Program 1986). The mention in Radford, Ahles, & Bell (1968) of M. grandiflora as occurring in Granville County made this new record seem plausible, though the habitat given ("bogs") was less felicitous. A review of specimens at the University of North Carolina Herbarium (NCU) by the first author revealed the specimen on which this record was based (NCU 225014: Granville County: Bog, 1.5 mi E of Hester, A.E. Radford 43945, 16 Jun 1961), and that this specimen matched the material found by LeGrand at Burner and differed morphologically from M. grandiflora in the same ways. Attempts by the first author in the late 1980s and early 1990s to relocate the Picture Creek population were unsuccessful. In 1971 and again in 1980, AM. and B.J. Harvill collected what they considered to be Marshallia obovata slightly to the north of the Picture Creek locality in Halifax County of south- central Virginia (collections cited below). One of the sites where the .Marshallia was collected, Difficult Creek, became a land conservation project by the Virginia Department of Conservation, and the populations of the state rare "M obovata" came under greater scrutiny from biologists of the Virginia Division of Natural Heritage, who found that populations of both M. obovata and the putative new species from Picture Creek were present, morphologically distinguishable and phenologically offset from one another (Figure 1). In both North Carolina and Virginia, the undescribed taxon has been informally accepted as a species warranting conservation tracking and monitoring (Buchanan & Finnegan 2010; Townsend 2009). Taxonomy. With four known populations (of which two are known to be extant, and two historical and possibly extirpated), this morphologically distinctive entity, associated with a distinctive habitat, phenologically separated from sympatic and syntopic populations of its congener M. obovata, highly imperiled by its rarity and the need for fire management of its habitat, warrants taxonomic recognition. Marshallia legrandii Weakley, sp. nov. (Figure 2). USA. North Carolina, Granville Co.: Picture Creek Diabase Barren, N of Butner, 22 Jul 2003, A.S. Weakley 7274 with L.M. Giencke and J.P. Perry III (holotype: NCU; isotypes: AUA MO, NCSC, NCU, NY, US). Paratypes: USA. North Carolina Granville Co.: Bog, 1.5 mi E of Hester, Radford 43945, 16 Jun 1961 (NCU 225014). Virginia Halifax Co.: Oak-pine woods 1 mi S of Difficult Creek on Rt. 719, 25 Jun 1972, Harvill 25539 (FARM [2 sheets], VPI 85782); border of dry, cut-over oak-hickory woods over basic rock, along SE side of Rt. 719, 1.1 mi SW of bridge over Difficult Creek, 3.3 mi E of Scottsburg, elev. 490 ft, common, 1 Jun 1995, Fleming 10448 (VPI 90521); Difficult Creek Heritage Preserve, mafic flats E of County Road 719, habitat malic woodlands, 27 Jun 2003, Weakley 7255 (NCU 568186, NCU 569188); roadside 3 mi E of Halifax, 9 Jun 1980, Harvill 41178 (LYN 42010). Known stations for the species are shown in Figure 3. Perennial, 60-80(-100) cm, fibrous-rooted, from caudices, and forming basal offsets. Stems erect, unbranched, striate, especially immediately below the head. Leaves basal and cauline, alternate; the first basal (most proximal) leaves often withering by anthesis, 1/3-1/2 as long as the next most proximal and longest basal and low cauline leaves, these longest leaves 15-25(-32) cm long (including the long petiole-like basal taper) and 7-20 mm wide, the apex acute to acuminate (rarely narrowly obtuse), the longest leaf on a plant (usually low cauline) 15-30 cm long, the leaves Weakley and Poindexter: New species of Marshallia 3 gradually reduced upwards, extending 2/3 to 4/5 of the length of the stem; well-dev eloped blades prominently 3-nerved, lanceolate to oblanceolate (sometimes linear-ob lanceolate. Heads strictly single. Involucres hemispheric to obconic, 20-25 nun in diameter (as measured phyllary tip to phyllary tip). Phyllaries 8-11 mm long, the broadest (outermost) phyllaries 2.5-3.7 mm wide, grading into narrower phyllaries inwards (and eventually into paleae), the apices acute to broadly acute, the distal surface densely glandular with both impressed glands and raised resin dots (Figure 4). Paleae acute-acuminate and only gradually and slightly dilated towards the apex, the distal surface glandular with both impressed glands and raised resin dots. Corollas pale to deep pink (Figure 5), lobes 5-7.5 x 0.7-1.1 mm. Cypselae mostly 3.0-3.2 mm long x mostly 1.5-1.6 mm wide (near the apex) and 0.8 mm wide (near the base), strigose, 5-angled, 10-ribbed. Pappus scales 1.1-1.3 mm long, scarious or hyaline, glabrous to scaberulous on the distal surfaces, the margins entire to scabridulous. Marshallia legrandii is readily distinguished from most members of the genus by the following features. Plants strictly single-headed (separating it fromM graminifolia, M. tenuifolia, M. ramosa, M. mohrii, M. caespitosa var. signata), leaves basally disposed (separating it from M trinervia), stem pubescent at least in the scapose portion below the head(s) (separating it from M trinervia), corollas pale to deep pink (separating it from M obovata var. obovata, M. obovata var. scaposa, M. ramosa, M. caespitosa var. caespitosa, M. caespitosa var. signata), M. legrandii shows closest similarities to M. obovata var.. obovata andM grandiflora but is readily separable from each. MarshalbM legrandii differs fromM obovata var. obovata in its greater stature (usually 6-9 dm tall vs. usually 3-5 dm tall), its larger heads (Figure 4), its corolla color (pale to deep pink vs. white to very pale pink: Figures 4, 5, 6, 7, 8), the greater length of the lower leafy portion of its stem (23-50 cm. long vs. 5-30 cm long; Figures 2, 5, 10), its later flowering (June-July vs. April-early June; Figure 1) even when growing at the same site, the shape of its basal and lower cauline leaves (narrowly oblanceolate, mostly 15-25 cm long including the petiole, mostly 7-20 mm wide, averaging about 10-20x as long as wide including the petiole, the apex acute to acuminate, vs. obovate to oblanceolate, mostly 6-10 cm long, mostly 8-14 mm wide, averaging about 6-10x as long as wide, the apex obtuse to rounded and often emarginated; Figures 2, 5, 10), the reduction upwards of the size of the stem leaves (gradually reduced upwards, several of the uppermost leaves ) Marshallia legrandii is indeed "le grand" Marshallia, taller thanM obovata, with which it has been confused, and among the tallest species in the genus. Habitat. The two known extant sites (Picture Creek Diabase Barren and Difficult Creek Natural Heritage Preserve) for Marshallia legrandii have notable similarities, in being remnants of mafic woodlands, savannas, or prairies that were once relatively common in the southeastern Piedmont (Noss 2012). Diabase, greenstone, and other mafic rocks in the southeastern Piedmont weather to clay-rich soils with hardpan characteristics, in which extreme fluctuations of soil moisture availability, cracking of soil during dry periods, flat landscapes creating large natural fire compartments, and occasional fires set by lightning and humans maintained "prairie-like" conditions suitable for calciphilic heliophytes. Such sites have been described as "Piedmont prairies" and are of great conservation, ecological, andbiogeographic interest, because of their large numbers of narrowly endemic or highly disjunct and regionally rare plant species (Barden 1997; Davis et al. 2002; Noss 2012). The habitats present at the third and fourth sites are more difficult to assess because they lack known extant populations of. Marshallia legrandii; the Hester location is over mafic rocks (diabase). Weakley and Fbindexter: New specie while Harvill's "'3 miles E of Halifax" collection appears not to be based on coarse-scale geologic mapping, but has not been searched for and the locality is rather vague. The Picture Creek Diabase Barren features many narrowly endemic and disjunct species tracked as rare by the North Carolina Natural Heritage Program and listed as Threatened or Endangered by the United States Fish and Wildlife Sendee and the North Carolina Plant Conservation Program (Buchanan & Finnegan 2010). Among the notable species co-occurring with the unusual population of Mar shalli a at the Picture Creek Diabase Barren are Solidago rigida var. glabrata, Solidago ptarmicoides, Symphyotrichum depauperatum, Echinacea laevigata, Carex meadii, Silphium terebinthinaceum, Baptisia australis var. aberrans, Ruellia humilis, Eryngium yuccifolium var. yuccifolium (North Carolina Natural Heritage Program 19S6; Buchanan & Finnegan 2010; all nomenclature and taxonomic concepts follow Weakley 2012). This set of species collectively is a mixture of very narrow endemics, broader endemics, and Midwestern disjuncts all associated with the regionally rare (in the Piedmont) combined conditions of 1 ) circumneutral soils with high base status, 2) frequent fire (at least historically), and open-canopy, sunny conditions. The Picture Creek community type is classified as the Quercus stellata - (Pinus echinata) / Schizachyrium scoparium - Echinacea laevigata - Oligoneuron album Woodland or Xeric Hardpan Forest (Northern Prairie Barren Subtype), given a Gl conservation rank, the most highly imperiled ranking possible in the NatureServe conservation ranking system (Schafale 2012; NatureServe 2012; Slapcinsky 1994). Highlighting the unusual edaphic conditions at the site is the classification of the soil at the site as a narrowly endemic series the Picture series, a fine, smectitic, thermic Vertic Argiaquoll (Natural Resources Conservation Agency 2012). Similarly, the Difficult Creek Natural Heritage Preserve supports lehct communities determined by montmorillonitic soils derived from mafic and ultramafic rock and the historic occurrence of fires maintaining an open canopy. Though much of the site was altered by conversion to loblolh pioe plantations in the 1980s, remnant patches of more natural vegetation remained, and some of the heliopb}tie species were able to persist in these sites and along roadsides, powerline rights-of-way, and a gas line right-of-way through the area. Now, with the area being restored by selective tree removal and prescribed fires, heliophytic taxa are reoccupying suitable habitats. The vegetation at the site is classified as a Quercus stellata - Carya (septentrionalis glabra) - (Quercus marilandica) I /"»". alatc ^SJnzaJn i nan scoparium - Piptochaetiam avenaceum) Woodland [= CEGL003714] (NatureServe 2012) or one of the Piedmont Hardpan Forest types in the Virginia community classification: Quercus stellata - Onerous alba - Carya glabra / Ulmus alata / P'prut hai'tntm auiiciLLiit'i - Selena oL^sitha Kxe4 (Southern Piedmont Hardpan Forest) (Fleming & Patterson 2012). Among the unusual and at least regionally rare taxa occurring with or near the Marshallia at Difficult Creek are Echinacea laevigata, Eryngium yuccifolium var. yuccifolium, Marshallia obovata var. obovata, Gillenia stipulata, Cirsium carolinianum, En the.} n he hum am.uluni, Aiumonc berlandieri, Lythrum alatum, Rhynchospora harveyi, Carex meadii, Tragia urticifolia, Ambrosia bidentata, Symphyotrichum laeve var. concinnum, and others (G.P. Fleming, pers. comm 2012; J.C. Ludwig, pers. comm. 2012; J.R. Townsend, pers. comm. 2012). Weakley and Fbindexter: New species of Marshallia Figure 1 0. Representative example of Marshallia obovata var. obov, Weakley and Poindexter: New species of Marshallia 14 Figure 11. Representative example of 'Marshallia grandiflt Weakley and Poindexter: New species of Marshallia 15 A New Key. We offer the following key to Marshallia with single heads and basally disposed leaves. A comprehensive key to the genus Marshallia will be provided in the near future. 1. Leafy portion of the stem 23-50 cm long, the miked peduncle 0.4-1.2* as long as the leafy portion of the stem; stem leaves reduced upward, the uppermost < 1/3 as long and wide as the largest leaves on the plant; basal leaves obovate to oblanceolate, the apex obtuse to acute or acuminate; outer well-developed phyllaries with acute to obtuse apex, the outer surface with abundant resin glands; corollas medium pink; flowering early June-July 2. Basal and lower cauline leaves (2-)3-13(-20) cm long (including the petiole), (5-)10-20(-30) mm wide, averaging about 6> as long as wide (including the petiole), the apex obtuse to rounded; pappus scales 1.5-2.2 mm long; plants (2-)3-5(-8.5) dm tall; achenes with absent or scattered resin dots between the ridges; Mountains of sw PA, WV, e KY, e TN and sw NC Marshallia grandiflora 2. Basal and lower cauline leaves 15-25(-32) cm long (including the petiole), (3-)7-12(-15) mm wide, averaging about 10* as long as wide (including the petiole), the apex acute to acuminate; pappus scales 1.0-1.3 mm long; plants (4-)6-9(-10) dm tall; achenes with copious resin dots between the ridges; Piedmont of nc NC and sc VA Marshallia legrandii 1. Leafy portion of the stem 0-20(-30) cm long, the naked peduncle 1.5-10* (or more) as long as the leafy portion of the stem; stem leaves (if present) not reduced upward, the uppermost > 1/2 as long and wide as the largest leaves on the plant; basal leaves obovate to oblanceolate, the apex obtuse to rounded (often emarginate); outer well-developed phyllaries with obtuse to rounded apex, with or without resin glands; corollas white to very pale pink; flowering late April-May(-early June). 3. Outer phyllaries lanceolate, apices both conspicuously tapered and apiculate; shale barrens, hillsides, and rocky limestone slopes, of se TX, w LA e OK, se KS, nw AR, and sw MO Marshallia caespitosa var. caespitosa 3. Outer phyllaries oblong-obovate, apices conspicuously rounded (though often also apiculate); glades, barrens, roadbanks, and mesic iongieaf pine savannas of sc VA, NC, SC, GA AL, and Panhandle FL. 4. Plant with 3-10 leaves on the lower stem, extending (5-)8-20(-30) cm up the stem; pappus scales (0.5-)0. 7-1.2(1. 5) mm long; plant (2-)3-5(-7) dm tall; outer surface of phyllaries and paleae generally lacking sessile resin glands (occasionally with a few punctate glands); Piedmont and rarely Coastal Plain from sc VA southward ... Marshallia obovata var. obovata 4. Plant scapose (all of the leaves basal) or nearly scapose, with 1-5 leaves extending l-5(-10) cm up the stem; pappus scales (1.0-)1.5-2.5(-3.0) mm long; plant (0.5-)1.5-3.5(-5.0) dm tall; outer surface of phyllaries and paleae with many punctate and sessile resin glands; Coastal Plain and rarely outer Piedmont from NC southward Marshallia obovata var. scaposa Future Studies. The authors and collaborators plan additional studies to resolve the appropriate taxonomic ranks of taxa in the "caespitosa" "scaposa" and "graminifolia" complexes. Curtis Hansen (AUA) has initiated molecular phylogenetic studies that should help resolve relationships in the genus and clarify the roles of allopolyploidy, autopolyploidy, and allopatric differentiation and speciation in the genus. Weakley and Poindexter: New species of Marshallia 16 ACKNOWLEDGMENTS We wish to thank Curtis Hansen and Irv Wilson for the use of photographs; Rob Evans, Cecil Frost Marj Boyer, and Lesley Starke (of the Plant Conservation Program, N.C. Department of Agriculture) for their stewardship and management of the Picture Creek Diabase Barren; Chris Ludwig, Johnny Townsend, and Gary Fleming (of the Virginia Division of Conservation) for their knowledge, stewardship, and conservation management of the Difficult Creek Natural Heritage Preserve; Curtis Hansen, Alice Broadhead Wines, Lisa Giencke, Stephanie Seymour, Carol Ann McCormick, Misty Franklin Buchanan. Laura Gadd, and Mike Schafale for discussions about the new species and its habitat; herbaria FARM LYN, NCU, VPI, and WILLI for access to specimens and specimen data; and Misty Franklin Buchanan, Chris Ludwig, Gary Fleming, Laura Gadd, Curtis Hansen, and Guy Nesom for reviews and suggestions that improved the manuscript. 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