Heuchera tuckasegeensis Pantinople, 2024

Heuchera tuckasegeensis Pantinople View in CoL , sp. nov. TYPE: USA. Transylvania Co., above Cold Mountain Road several miles from Toxaway, 4 October 2013, R.A. Folk 230 (holotype: OS!).

Heuchera tuckasegeensis resembles Heuchera parviflora var. parviflora but is distinguished by its sparsely puberulent petioles (vs. densely villous), deeper leaf sinuses (0.9–1.3 vs. 0.6–0.7 per unit leaf length), and shorter styles (1.4–1.6 mm vs. 2.2–2.3 mm) and stamens (1.3–1.6 mm vs. 1.9–2.1 mm).

Perennial herb, acaulescent. Petioles sparsely puberulent to nearly glabrous (trichomes 0.25–0.35[–0.65] mm long), 8.86–17.51 cm long. Leaf blades 4.3–8.7 cm wide, 3.1–5.3(–7.9) cm long (from convergence of veins to apex), reniform, shallowly to deeply cordate, relatively deeply divided into 5 primary lobes; sinuses between leaf lobes 3.88–5.21 mm deep; teeth obtusely triangular to crenate, 1.79–2.5 mm long, 5.53–9.22 mm wide; abaxial lamina remotely viscid, strigose; adaxial lamina similarly vestitured (trichomes 0.13–0.45 mm long); leaf margin obscurely ciliate. Inflorescences thyrses (racemes of scorpioid cymes), 20.84–27.07 cm long, diffuse, interrupted, with 1–3 leaf-like bracts along the primary axis of the thyrse below the most proximal cymule, and a reduced bract at each cymule and flower node, 2.68–4.83 mm long, primary axis puberulent; cymules 2–7 flowered, 2.11–3.34 cm long, diffuse (pedicels of lower cymule first order flower 5.06–8.52 mm long), lower cymules dichasial but distal-most cymules becoming monochasial. Flowers 1.82–2.68 mm long, (1.37–) 1.50–1.81 mm wide (at the bottom of hypanthium), white, campanulate, external surface villous, orientation pendent; sepals triangular, 0.74–1.82 mm long; petals narrowly spatulate with a long claw, recurved, 1.92–2.66 mm long; stamens 1.28–1.55 (2.33) mm long; styles 1.39–1.62 (2.01) mm long, stigmas capitate. Capsules 4.22–5.47 mm long, 2–2.58 mm wide, ovoid. Seeds (0.39–) 0.45–0.62 mm long, widely elliptic, black, almost smooth with testa cells arranged in low ridges, the margins obscurely undulate. Figures 6 View FIG , 7 View FIG .

Phenology —Flowers from June to October and fruits from June (no specimens were available to confirm the end of the fruiting period).

Distribution —Southwestern tip of North Carolina, USA, in Jackson County along the east fork of the Tuckasegee River, and in Transylvania County around Panthertown Valley near Cold Mountain and Lake Toxaway ( Fig. 8 View FIG ).

Habitat —Rockhouses behind waterfalls, shaded areas, rock outcrops, crevices, and ledges on cliffs, on highly acidic gneiss, (805–) 1073–1280 m.

Conservation —Currently only known from seven localities across a narrow range of approximately 10 km; a species of interest for conservation listing given its rarity, regional endemism, and genetic distinctness, but still warrants further field data.

Associates — Leucothoe axillaris D.Don , Parnassia asarifolia Vent. , Houstonia serpyllifolia Graham , Oxypolis rigidior (L.) Raf., Thalictrum clavatum Hook , Eurybia divaricata (L.) G.L. Nesom, Luzula echinata (Small) F.J.Herm. , Kalmia latifolia L., Viburnum nudum var. cassinoides (L.) Torr. & A.Gray, Asplenium montanum Willd. , Vittaria appalachiana Farrar & Mickel , Heuchera villosa Michx. , and species in the liverwort order Jungermanniales .

Etymology —Anglicized Cherokee (“turtle place”), named for the Tuckasegee River, corresponding to the primary distribution of this taxon. Epithet to be pronounced in six syllables (i.e. “tuckasege€ ensis”).

Other Specimens Examined — USA. — NORTH CAROLINA: Jackson Co., Maidenhair Falls above Lake Fairfield , 9 August 1951, R.K. Godfrey 51818 ( DUKE) ; Jackson Co., Bonas’ Defeat, East fork of Tuckasegee River , 23 August 1951, R.K. Godfrey 52017 ( NY) ; Jackson Co., Tuckasegee River gorge, Bonas’ Defeat cliffs, 20 July 1972, D. Pitillo 9361 ( WCUH) ; Jackson Co., Bonas’ Defeat cliffs, Tuckasegee River gorge, 7 July 1973, D. Pitillo 4591 ( WCUH) ; Jackson Co., Wolf Creek gorge of Canada Community , 805 m, 6 April 1974, D. Pitillo 6543 ( WCUH) ; Jackson Co., near Bonas’ Defeat, East fork of Tuckasegee River , 15 September 1974, E.F. Wells 3279 ( NCU) ; Jackson Co., South slopes of Shelton Pisgah Mountain along Little Green Creek , north of Cold Mountain Gap , 1159 m, 25 November 1989, D. Pitillo 10538 ( WCUH) ; Jackson Co., Panthertown Valley on Shelton Pisgah Mountain, Northwest end above Little Greenland Creek , 1128 m, 1 August 1990, D. Pitillo 10659 ; Jackson Co., North of Camp Merrie Woode at Fairfield Lake , Twin Falls grotto on Trays Island Creek , 1073 m, 17 May 1991, D. Pitillo 10753 ( WCUH) ; Jackson Co., Wolf Creek Falls below dam, 854 m, 23 June 1994, D. Pitillo 11691 ( WCUH) ; Transylvania Co., near Camp Toxaway on Cold Mountain Road , 7 August 1949, A.E. Radford 4819 ( NCU) ; Transylvania Co., Showerbath Falls East of Cold Mountain Gap , 1098 m, 15 July 1988, D. Pitillo 9984 ( WCUH) ; Transylvania Co., Panthertown Valley, Cold Mt. , 25 May 1990, S. Wiser 90212 ( NCU) ; Transylvania Co., Panthertown Valley, Cold Mountain , 1189 m, 10 June 1993, D. Pitillo 11255 ( WCUH) ; Transylvania Co., Shower Falls on Cold Mountain Road , 23 April 2006, E. Schwartzman s. n. ( UNCA) .