Heracleum piliferum Kljuykov & Lyskov, 2021

Kljuykov, Eugene, Lyskov, Dmitry, Ukrainskaja, Uliana, Samigullin, Tahir & Terentieva, Elena, 2021, Heracleum piliferum (Apiaceae), a new species from central Nepal, Phytotaxa 500 (3), pp. 166-178 : 175

Heracleum piliferum Kljuykov & Lyskov , sp. nov. ( Figs. 2–6 , 7a–c )

Type :— NEPAL. Central Nepal , southern slopes of Annapurna mountain massif, valley of Modi Khola, right bank, between Deorali (Deurali) and Machhupuchhare Base Camp. Alt. 3400-3750 m, 28º30′N, 83º52′E, 23 October 1999, Pimenov et Kljuykov 20 ( MW, holotype mounted on 2 cross-labelled sheets: sheet 1—leaf part, MW0595742 ; sheet 2—generative part, MW0595743 ; isotype MW0595734 ) .

Perennial herbaceous plants with cylindrical taproot. Stems solitary, hollow, branched in upper part, costate and pubescent in lower part, middle and upper parts glabrous, 100–120 cm tall and up to 15 mm ⌀ at base, covered with soft remains of sheaths and older leaves. Basal leaves with long pubescent petioles up to 25–30 cm long enlarged to narrow sheaths; pubescence consisting of long, decurved, acute hairs. Abaxial surface of leaves with thin pubescence, adaxial surface with sparse pubescence; leaf blades 20–30 cm long and 14–19 cm wide, obovate, pinnate or 2-pinnate, with 3 pairs of basal segments, basal segments on petiolules 3 cm long, secondary segments with short petiolules and crenulate margin; terminal segments obovate or broadly elliptic 8–10 cm long and 6–8 cm wide, decurrent at base, with three triangular lobes; secondary segments triangular or obovate, 5–6 cm long and 4–5 cm wide, shallow tripartite, cuneate at base; stem leaves with short triangular sheaths. Terminal umbel larger than other umbels, up to 20 cm ⌀, number of rays 22–30, rays 4–9 cm long, unequal, straddling, nearly glabrous; bracts deciduous with mature fruits; number of bracteoles 4–6, bracteoles filiform and herbaceous. Umbellets up to 3 cm ⌀, with up to 25 flowers, peduncles nearly glabrous, thin, rounded, slightly unequal, up to 12 mm long. Mericarps homomorphic, strongly dorsally compressed, glabrous, up to 12 mm long, 7–8 mm wide, broadly obovate, nearly circular; carpophore bifurcate to base, calyx teeth obscure, stylopods conical, styles 1–1.5 mm long, decurved or curved; only primary ribs present; ribs unequal, dorsal ribs filiform, lateral ribs broadly winged, thickened, straight, with entire margin; commissure broad; secretory ducts between ribs solitary, on the end clavate, cover about 2/3 of mericarp’s length or more, commissural secretory ducts paired, short (about ½ of mericarp’s length), sometimes obscure; endosperm flat at commissural side.

Etymology: —The specific epithet refers to a feature of the new species, the petioles of basal leaves having a dense pubescence consisting of thin and long decurved hairs.

Phenology: —Flowering probably in July and August; fruiting in September and October.

Distribution: —The species is only known from the type locality in Nepal.

Figures

FIGURE 2 Heracleum piliferum, holotype sheet 1 (MW 0595742). Courtesy of the National Depository Bank of Live Systems, Moscow State University.

FIGURE 3 Heracleum piliferum, holotype sheet 2 (MW 0595743). Courtesy of the National Depository Bank of Live Systems, Moscow State University.

FIGURE 4 Illustration of Heracleum piliferum (from the holotype), leaves and lower part of stem.

FIGURE 5 Illustration of Heracleum piliferum (from the holotype), umbel and upper part of stem.

FIGURE 6 Illustration of Heracleum piliferum (from the holotype), mericarp dorsal view.

FIGURE 7 Mericarp cross sections (a, d), dorsal view (b, e) and commissural view (c, f), scale bars 2 mm, CAV means cavity: a–c Heracleum piliferum; d–f H. forrestii (type specimen).