Hexastylis Raf. (Aristolochiaceae)

With eleven species represented in the state, North Carolina is the epicenter of diversity of Hexastylis. The only species of Hexastylis to have been listed at the federal level was H. naniflora (Fed T, S3 G3). The species was delisted effective Aug 2025. It is retained here as a post-delisting monitoring plan is in effect until 2030. The species remains state listed (T) at this time, along with Hexastylis contracta (State E, S1 G3). Hexastylis rhombiformis and H. rosei are also of conservation concern and tracked by NHP.

Formerly federally listed taxon—Hexastylis naniflora (Fed T [delisted 2025], State T | S3 G3)

Habitat. Like most species of Hexastylis, H. naniflora can be found on acidic soils. It is usually associated with hardwood bluffs and slopes adjacent to creeks or other bodies of water.

Range. Endemic to North and South Carolina.

Note. USFWS proposed delisting this species in early 2021 with the public comment period ending 25 June 2021. The final rule on delisting was made in 2025 (delisting effective as of 7 Aug 2025).

Additional resources. NHP | Recovery Plan | 5-yr review | Proposed delisting | SSA | PDM

Key to Hexastylis in North Carolina

Key adapted from Blomquist (1957), Gaddy (1987), Whittemore and Gaddy (1997 [FNA]), and Weakley (2008). Photos by Krings, unless otherwise indicated. Maps courtesy of USDA PLANTS and the North Carolina Natural Heritage Program.

1. Style extension distinctly bifid to stigma; leaves triangular to ovate-sagittate or subhastate, variagation (if present) between secondary veins...H. arifolia

Leaf of Hexastylis arifolia (Photo: Krings)

Leaves of Hexastylis arifolia (Photo: Krings)

Flower of Hexastylis arifolia (Photo: Krings)

Flower of Hexastylis arifolia (Photo: Krings)

Flower of Hexastylis arifolia (Photo: Krings)

Flower detail of Hexastylis arifolia (Photo: Krings)

Flower detail of Hexastylis arifolia (Photo: Krings)

Hexastylis arifolia
(A-B, var. arifolia: common, mesic to dry deciduous forests, Mt, Pd, CP; C, var. ruthii: uncommon, ultramafic outrop barrens, upland forests, Mt)

Line drawings reproduced with permission of the publisher from: Hugo L. Blomquist. "A revision of Hexastylis of North America". Brittonia 8(4): 255–281. (c) 1957. The New York Botanical Garden Press, Bronx. [http://www.jstor.org/stable/2804978]

1’. Style extension notched or divided at the apex, but not bifid to the stigma; leaves cordate, subreniform, orbicular, or triangular-cordate, variagation (if present) along secondary veins...2.

2. Leaf margins minutely toothed...H. rosei

Habit of Hexastylis rosei (Photo: Krings)

Leaf of Hexastylis rosei (Photo: Krings). Note minute teeth along leaf margins, as well as the impressed midvein.

Leaf of Hexastylis rosei (Photo: Krings). Note minute teeth along leaf margins, as well as the impressed midvein. In Galax urceolata (inset), the midvein is distinctly raised.

Leaf of Hexastylis rosei (Photo: Krings).

Flower of Hexastylis rosei (Photo: Krings).

Flowers of Hexastylis rosei (Photo: Krings).

Flower of Hexastylis rosei (Photo: Krings).

Hexastylis rosei
(rare [SR-L, S1 G1]; acidic cove forests; Mt)

2'. Leaf margins entire...3.

3. Inner surface of calyx lobes pilose, many trichomes whitish or translucent at least in part; leaves not clumped, spread out along long-creeping rhizomes...H. lewisii

Habit of Hexastylis lewisii. Note diffuse, non-clumping, arrangement along elongate rhizome (Photo: Krings)

Leaf of Hexastylis lewisii (Photo: Krings)

Leaf of Hexastylis lewisii (Photo: Krings)

Calyx of Hexastylis lewisii (Photo: Krings)

Calyx of Hexastylis lewisii with free lobes removed; showing pilose trichomes in throat (Photo: Krings)

Pilose pubescence of inner calyx of Hexastylis lewisii (Photo: Krings)

Androecium and gynoecium of Hexastylis lewisii (Photo: Krings)

Hexastylis lewisii
(rare; pocosin ecotones and upland forests; Pd, CP)

Line drawings reproduced with permission of the publisher from: Hugo L. Blomquist. "A revision of Hexastylis of North America". Brittonia 8(4): 255–281. (c) 1957. The New York Botanical Garden Press, Bronx. [http://www.jstor.org/stable/2804978]

3’. Inner surface of calyx lobes puberulent, trichomes usually purplish or reddish throughout; leaves usually strongly clumped...4.

4. Calyx tube broadly urceolate-campanulate or rhombic-ovate...5.

5. Calyx tube urceolate-campanulate, lobes 10–22 mm wide at base...H. shuttleworthii var. shuttleworthii

Habit of Hexastylis shuttleworthii (Photo: Krings)

Leaf of Hexastylis shuttleworthii (Photo: Krings)

Leaf of Hexastylis shuttleworthii (Photo: Krings)

Calyx tube of Hexastylis shuttleworthii (Photo: Krings)

Interior of Hexastylis shuttleworthii (Photo: Krings)

Interior calyx surface of Hexastylis shuttleworthii (Photo: Krings)

Interior of Hexastylis shuttleworthii (Photo: Krings)

Hexastylis shuttleworthii var. shuttleworthii
(uncommon; acidic deciduous forests, frequently along creeks; Mt)

Line drawings reproduced with permission of the publisher from: Hugo L. Blomquist. "A revision of Hexastylis of North America". Brittonia 8(4): 255–281. (c) 1957. The New York Botanical Garden Press, Bronx. [http://www.jstor.org/stable/2804978]

5’. Calyx tube rhombic-ovate (broadest near the middle), lobes 3–8 mm wide at base...6.

6. Internal calyx tube reticulations absent or poorly developed, ridges < 1.0 mm if present; ovary ca. 1/3 inferior ...H. contracta

Leaf of Hexastylis contracta (Photo: Krings)

Hexastylis contracta (Photo: Krings)

Calyx lobes of Hexastylis contracta (Photo: Krings)

Internal throat hairs of Hexastylis contracta (calyx lobes removed; Photo: Krings)

Androecium and gynoecium of Hexastylis contracta. Note also the very low ridges on the internal tube walls (Photo: Krings)

Low internal ridges at base of tube of Hexastylis contracta (Photo: Krings)

1/3 inferior ovary of Hexastylis contracta (Photo: Krings)

Hexastylis contracta
(rare [State E, S1 G3]; acidic deciduous forests; Mt)

Line drawings reproduced with permission of the publisher from: Hugo L. Blomquist. "A revision of Hexastylis of North America". Brittonia 8(4): 255–281. (c) 1957. The New York Botanical Garden Press, Bronx. [http://www.jstor.org/stable/2804978]

6’. Internal calyx tube reticulations well developed, ridges 1.5–2 mm tall; ovary superior...H. rhombiformis

Leaf of Hexastylis rhombiformis (Photo: Krings)

Calyx tube of Hexastylis rhombiformis (Photo: Krings)

Variation in calyx tube of Hexastylis rhombiformis (Photo: Krings)

Variation in calyx tube of Hexastylis rhombiformis (Photo: Krings)

Calyx lobes of Hexastylis rhombiformis (Photo: Krings)

Tall internal ridges of calyx tube of Hexastylis rhombiformis (upper portion of tube removed; Photo: Krings)

Androecium and gynoecium, as well as calyx wall, of Hexastylis rhombiformis (Photo: Krings)

Hexastylis rhombiformis
(rare [SR-L, S3 G3]; acidic deciduous forests, frequently along creeks; Mt)

4’. Calyx tube cylindrical to narrowly cylindro-urceolate...7.

7. Calyx tube cylindrical to narrowly cylindro-urceolate, lobes 2–4 mm long, erect to slightly spreading...H. virginica

Leaf of Hexastylis virginica (Photo: Krings)

Hexastylis virginica (Photo: Krings)

Hexastylis virginica (Photo: Krings)

Hexastylis virginica (Photo: Krings)

Hexastylis virginica (Photo: Krings)

Hexastylis virginica (Photo: Krings)

Hexastylis virginica (Photo: Krings)

Hexastylis virginica
(common; upland forests; Mt, Pd, CP)

Line drawings reproduced with permission of the publisher from: Hugo L. Blomquist. "A revision of Hexastylis of North America". Brittonia 8(4): 255–281. (c) 1957. The New York Botanical Garden Press, Bronx. [http://www.jstor.org/stable/2804978]

7’. Calyx tube cylindrical, lobes 4–15 mm long, moderately spreading to reflexed...8.

8. Calyx tube usually wider than long, orifice wider than the lobe lengths (lobes 9–16 x 8–16 mm); ovary ca. 1/3 inferior...9.

9. Calyx tube 12–25 mm long, leaves always densely variegated...H. minor

Hexastylis minor (Photo: Krings)

Hexastylis minor (Photo: Krings)

Hexastylis minor (Photo: Krings)

Hexastylis minor (Photo: Krings)

Hexastylis minor (Photo: Krings)

Trichomes on calyx lobe of Hexastylis minor (Photo: Krings)

Hexastylis minor (Photo: Krings)

Hexastylis minor
(common; dry to moist forests and pocosin margins; Pd, CP)

Line drawings reproduced with permission of the publisher from: Hugo L. Blomquist. "A revision of Hexastylis of North America". Brittonia 8(4): 255–281. (c) 1957. The New York Botanical Garden Press, Bronx. [http://www.jstor.org/stable/2804978]

9'. Calyx tube 8–18 mm long, leaves sparsely variegated to not variegated...H. sorriei

Hexastylis sorriei habitat (Photo: Krings)

Hexastylis sorriei leaf (Photo: Krings)

Hexastylis sorriei leaf (Photo: Krings)

Hexastylis sorriei flower (Photo: Krings)

Hexastylis sorriei flower (Photo: Krings)

Hexastylis sorriei flower (Photo: Krings)

Hexastylis sorriei flower (Photo: Krings)

Hexastylis sorriei
(infrequent; pocosin ecotones, margins of sandhill seeps [often with Osmundastrum cinnamomeum and Toxicodendron vernix]; Pd/CP)

8’. Calyx tube at least as long as wide or longer, orifice narrower than the lobe lengths; ovary superior or
half-inferior...10.

10. Calyx tube 7–14 mm wide, lobes 6–17 mm wide; ovary superior; leaves typically not variegated
...H. heterophylla

Leaf of Hexastylis heterophylla (Photo: Krings)

Hexastylis heterophylla (Photo: Krings)

Hexastylis heterophylla (Photo: Krings)

Hexastylis heterophylla (Photo: Krings)

Hexastylis heterophylla (Photo: Krings)

Hexastylis heterophylla (Photo: Krings)

Androecium and gynoecium of Hexastylis heterophylla (Photo: Krings)

Hexastylis heterophylla
(common; dry to mesic forests; Mt, Pd)

Line drawings reproduced with permission of the publisher from: Hugo L. Blomquist. "A revision of Hexastylis of North America". Brittonia 8(4): 255–281. (c) 1957. The New York Botanical Garden Press, Bronx. [http://www.jstor.org/stable/2804978]

10’. Calyx tube 4–7 mm wide, lobes 4–7 mm wide; ovary half-inferior; leaves typically variegated...H. naniflora

Hexastylis naniflora habitat (Photo: Krings)

Hexastylis naniflora habitat (Photo: krings)

Hexastylis naniflora leaves (Photo: Krings)

Hexastylis naniflora flower (Photo: Krings)

Hexastylis naniflora flower (Photo: Krings)

Hexastylis naniflora flower (Photo: Krings)

Hexastylis naniflora flower (Photo: Krings)

Hexastylis naniflora
(rare [Fed T (until 7 Aug 2025), State T, S3 G3]; acidic deciduous forests; Pd; late winter to spring)

Line drawings reproduced with permission of the publisher from: Hugo L. Blomquist. "A revision of Hexastylis of North America". Brittonia 8(4): 255–281. (c) 1957. The New York Botanical Garden Press, Bronx. [http://www.jstor.org/stable/2804978]

Similar species

Leaves of Asarum canadense s.l. may at first glance be taken for Hexastylis. However, note the distinct differences in flower structure in the images below. In contrast to Hexastylis, the flowers of Asarum canadense s.l. are conspicuously pubescent and the perianth lobes are not completely fused into a tube.

Leaf of Asarum canadense s.l. (Photo: Krings)

Flower of Asarum canadense s.l. (Photo: Krings)

Flower of Asarum canadense s.l. (Photo: Krings)

Flower of Asarum canadense s.l. (Photo: Krings)

Flower of Asarum canadense s.l. (Photo: Krings)

Flower of Asarum canadense s.l. (Photo: Krings)

Flower of Asarum canadense s.l. (Photo: Krings)