A NEW SPECIES OF HEXASTYLIS (ARISTOLOCHIACEAE)
FROM THE SANDHILLS OF NORTH AND SOUTH CAROLINA

L. L. GADDY

terra incognita

125 South Edisto Avenue

Columbia, South Carolina 29205

llgaddy@bellsouth.net

ABSTRACT

Hexastylis sorriei is a new species of Hexastyl is from the Sandhills of the Inner Coastal Plain
of the Carolinas. It is closely related to Hexastylis minor and lias frequently been mistaken for

Hexastylis virgin ica.

KEY WORDS: Hexastylis, Hexastylis minor, Hexastylis sorriei, Hexastylis virginica, Sandhills,

North Carolina, South Carolina.

In the spring and summer of 2004, I conducted fieldwork at Camp Mackall, a United States
military installation just south of Fort Bragg in Cumberland Co., North Carolina, in the Sandhills of
the Inner Coastal Plain physiographic province. On several occasions, I encountered a strange
Hexastylis growing on wet, acidic slopes under cinnamon fern (Osmunda cinnamomea) along the
margins of streamhead pocosins. Most plants had only a leaf or two, and only a few plants had
flowers. The calyces of the flowers were similar to those of Hexastylis minor (Ashe) Blomquist, a
North Carolina-South Carolina -Virginia endemic found on clayey soils of the Piedmont (see Gaddy
1987 for distribution maps). A review of herbarium specimens from the area revealed that most
Hexastylis collections from the North Carolina Sandhills had been identified as H. minor or H.
virginica (L.) Small. Later, in 2005, while annotating specimens at the herbarium at the University of
North Carolina at Charlotte, I saw a specimen of Hexastylis from an acidic, ecotonal habitat in the
Sandhills of Chesterfield Co., South Carolina. It was determined to be H. minor and had been
previously annotated by me as "possibly" H. virginica. Although most Hexastylis species are
acidophils, I found it strange that this sandhill Hexastylis, found in hyperacidic soils, could be H.
minor, a common Piedmont species known for its ability to grow on the less acidic Piedmont clays.
Furthermore, the calyx lobes on all the flowers of the sandhill plants I had seen in the field and the
ones I had annotated were spreading (not erect as in H. virginica) and too long to be called H.
virginica. I, therefore, decided to take a closer look at these sandhill plants.

In the spring of 2005 through the spring of 2011, I made additional field trips to Fort Bragg
and the Sandhills of North and South Carolina and saw the same plant at various wet, acidic habitats
— even growing with Dionaea muscipula at one site and with Sarracenia purpurea and Sarracenia
rubra at another. I collected numerous flowers at each site for morphological studies. In the spring
of 2005, 1 visited the Chesterfield Co. population and studied fresh flowers from there. In the winter
of 2007, I reviewed the holdings of the herbarium at the University of North Carolina-Chapel Hill
(NCU). In the spring of 2007, 1 revisited most of the populations identified as Hexastylis minor and
H. virginica in Cumberland, Harnett, Hoke, Moore, Richmond, Robeson, and Scotland counties.
None of the populations I visited in the xeric Sandhills of North Carolina appeared to be either good
H. minor or H. virginica.

After several years of observation and analysis of the floral and leaf characteristics of these
sandhill Hexastylis plants, I have concluded that these populations represent a new species of
Hexastylis, which I am calling Hexastylis sorriei, the Sandhills Heartleaf I take pleasure in naming

this species after Mr. Bruce A. Sorrie, Research Associate at the UNC-Chapel Hill Herbarium,
sandhill botanist and naturalist.

HEXASTYLIS SORRIEI Gaddy, sp. nov., Figures 1 and 3. TYPE: USA. North Carolina. Hoke
Co.: In burned ecotonal area under Osmunda cinnamomea, along E side of Jumper Creek just
S of Plank Road, ca. 5 mi NNW of Raeford, on Fort Bragg Military Installation, 14 May
2007, L.L. Gaddy 05 1407 (holotype: USCH).

Hexastyli minor ( \-i«w) LluimiuM afLms se 1 dJi> 1 I >ln-> non variegatis vel leviter
variegatis; Hexastyli virginicae (L.) Small affinis sed differt lobis calycis patentibus (non erectis).

Rhizomes: internodes short, leaves crowded at rhizome apex. Leaf blades: variegated to not

variegated, cordate, usually 2-8 leaves per plant. Flowers: usually 2-4 flowers per plant, calyx tube
cylindric to cylindric-campanulate, sometimes with a prominent transverse ridge (flare) just below the
sinuses, calyx length 8-18 mm, calyx width 8-16 mm (flare to 16 mm wide), inner surface
longitudinally ridged with reticulations between ridges, reticulation deq3 and finely dissected, calyx
tube thin and easily torn, calyx lobes 4-8 mm long, spreading, 6-8 mm long, 10-12 mm wide,
adaxially puberuient; stamen connective not extending beyond pollen sacs; ovary ca, 1/3 inferior,
ovules 6 per locule; style notched at apex (format follows Whittemore and Gaddy 1997).

Hexastylis sorriei is most similar and probably most closely related to Hexastylis minor. It
differs from H. minor, however, in many ways: 1) the leaves of H. sorriei display sparse to no
variegation, while those of//, minor are densely variegated, almost to the point of being white in the
central portion of the leaf, as shown in Fig. 2; 2) the flowers of H. sorriei are generally smaller than
those of//, minor and have greater color variation (the flowers of//, minor are nearly always purple
or whitish-purple, Fig. 4 — those of H. sorriei often have white or greenish-white bases and are
frequently greenish when they first open); and 3) the internal ridged reticulation in the flowers of //.
sorriei is usually more finely dissected and deeper than that found in the flowers of// minor.

Additional collections examined: NORTH CAROLINA. Cumberland Co.: Fort Bragg
Military Reservation, south side of Little River, 1.1 mi E of Lamont Road, 17 April 1993, B.A. Sorrie
(NCU); sandy area above cypress pond with Vaccinium, Gordon Butler Nature Preserve, Hope Mills,
30 March 1990, D.R Jensen 3 (NCU). Moore Co.: deciduous thicket near stream, Weymouth
Woods— SNP, Southern Pines, 08 April 1973, J.H. Carter, 453 (NCU). Richmond Co.: bay forest,
Hitchcock Creek, 3 !4 miles west of Marston, 19 May 1956, A.E. Radford 11356 (NCU); Robeson
Co.: margin of pocosin 3 Vi mi. northwest of Parkton near county line, 5 April 1958, R.R Britt 1616
(NCU). SOUTH CAROLINA Lancaster Co.: in thicket margins of streamhead pocosin with
Osmunda cinnamomea and Pothergilla gardenii on headwaters of unnamed creek approximately 3 mi
SSE of Kershaw (0.4 mi NE of jet of County Roads 770 and 769), 4 May 2007, /./. Gaddy 050407
(USCH). Chesterfield Co.: Carolina Sandhills National Wildlife Refuge, thickety woods at Lake 12.
2 May 1982, Tom Daggy 8953 (UNCC).

There is a Hexastylis specimen from Darlington Co., South Carolina, that is labeled
Hexastylis virginica. This specimen has been cited (Blomquist 1957; Radford et al. 1968; Gaddy
1987) as the only South Carolina record for this species. I revisited the site (the boggy edges of a
sandhill pond) but could not find any Hexastylis plants. Based on the habitat, however, I am
confident that this collection was from a population of//, sorriei. Hexastylis virginica probably does
not occur in South Carolina. Darlington Co.: Kilgore's Pond woods, 21 Apr 1932, Budd Smith s.n.
(NCU).

Gaddy: New spezlesof Ha*3sty/ts

Figure 1. Hexasiyiis sorriei leaves emerging from soil after a fire (note lack of variegation).

Hexasiyiis sorriei is noteworthy in its ability to withstand and prosper in an ecotonal habitats
exposed to frequent, hot fires. Here, the Sandhills Heartleaf grows with Nyssa bijlora, Acer rubrum,
[rarely with Chamaecyparis thyoides, Osmunda cinnamomea, Clethra olnifolia. Be/, glabra, Hex
coriacea, Lyonia lucida, Cyrilla racemiflora, Fothergilla gardenii, Magnolia virginiana, Persea
paluslris, Sarracenia rubra, Sarracenia purpurea. Sphagnum spp., and. very rarely. Dionaea
muscipula (the latter only in Norm Carolina). The first year after fire, Hexasiyiis sorriei sprouts and
flowers. The second year after fire, as its habitat gradually becomes more crowded with stems of
other species, it produces fewer ieaves and flowers. After several years without fire, most plants have
only one or two leaves and flowers are very hard to find. Home historic locations where tire has been
absent fa' decades have no plants at all today. Even with fire, it produces smaller clumps than most
species of Hexasiyiis — a "large" clump of H. sorriei has about 8 leaves and 4 flowers, while in other
species of Hexascylis, healthy clumps often have around 20 leaves and nearly as many Rowers.
Hexasiyiis sorriei can generally be said to be rare and local Fort Bragg and Camp Mackall, where
annual burning is widespread, are the only locations where the Sandhills Heartleaf can be said to be
common.

Gaddy: New species of Hexastylis 4

Figure 2. Hexastylis minor — typical densely \

Key to Hexastylis sorriei and Related Species

1 . Calyx tube cylindrical to urceolate, lobes 2-4 mm long Hexastylis virginica

1 . Calyx tube cylindrical, lobes 4-1 5 mm long.

2. Calyx tube longer than wide.

3. Calyx tube opening 8-12 mm wide, greater than V 2 lobe length Hexastylis heterophylla

3. Calyx tube opening 3-8 mm wide, less than V2 lobe length Hexastylis naniflora

2. Calyx tube about as wide as long, or wider than long.

4. Calyx tube about as long as wide, opening width less than the lobe length

Hexastylis heterophylla

4. Calyx tube wider than long, opening width greater than the lobe length.

5. Calyx tube 12-25 mm long, leaves always densely variegated Hexastylis minor

5. Calyx tube 8-18 mm long, leaves sparsely variegated to not variegated . Hexastylis sorriei

ACKNOWLEDGEMENTS

I would like to thank Dr. Alan Weakley, Curator of the Herbarium, University of North
Carolina, and Mr. Bruce Sorrie, Research Associate at the UNC Herbarium, for reviewing several
drafts of this paper. Thanks also go to Dr. John Nelson of the A.C. Moore Herbarium of the
University of South Carolina for assisting me with vouchers of this species. Initial observations of
this species at Fort Bragg, North Carolina, were made during fieldwork that was part of an
endangered species contract between the U. S. Army and Ecological Associates of Wadmalaw Island,
SC. Thanks to Mr. Nick Roark of Ecological Associates for allowing me to participate in that
inventory.

LITERATURE CITED

Blomquist, H.L. 1957. A revision of Hexastylis of North America. Brittonia 8: 255-281.

Gaddy, L.L. 1987. A review of the taxonomy and biogeography of Hexastylis (Aristolochiaceae).

Castanea52: 186-196.
Radford, A.E., H.E. Ahles, and C.R. Bell. 1968. Manual of the Vascular Flora of the Carolinas.

Univ. of North Carolina Press, Chapel Hill.
Whittemore, A.T. and L.L. Gaddy. 1997. Hexastylis (Aristolochiaceae). Pp. 54-58, in Flora of North

America Editorial Committee (eds.). Flora of North America, Vol. 3. Oxford Univ. Press,

New York.

Figure 3. Flowers of Hexastylis sorriei Gaddy.

Figure 4. Hexastylis flowers left to right: H. virginica (note short, erect calyx lobes), H
heterophylla, H minor, and H naniflora. Note white bases of heterophylla and naniflora.