Dichoropetalum viarium Lyskov & Kljuykov, 2021

Lyskov, Dmitry, Zarre, Shahin, Samigullin, Tahir & Kljuykov, Eugene, 2021, Dichoropetalum viarium (Apiaceae), a new species from Lorestan Province, Western Iran, Phytotaxa 525 (1), pp. 15-25 : 18-23

Dichoropetalum viarium Lyskov & Kljuykov , sp. nov. ( Figs. 2–5 )

The new species is related to D. paucijugum , D. aromaticum , and D. chryseum and differs from them in the stem height, shape, and diameter, branching, shape of the terminal leaf lobes, shape of the bracteoles, shape and size of the mericarps, and shape of the stylopodium.

Type:— IRAN. Lorestan Province: 2 km NE from Sepid Dasht , rocky outcrops, alt. 1200 m, 33.226967° N, 48.917366° E, 18 June 2018, Lyskov 115-IR-18 ( MW, holotype mounted on 2 cross-labelled sheets barcodes: MW0595736, MW0595738) .

Perennial monocarpic herbaceous plant with vertical taproot 15–20 mm ∅, glabrous, green-brownish ( Figs. 2–3 , 5 ). Stems 80–130 cm, 7–15 mm ∅ at base, solitary, erect, solid, covered with soft remains of sheaths and older leaves, rounded at base, slightly angular, in middle part slightly grooved, in upper part rounded, branched from base, foliaceous; internodes short, their number up to 15. Inflorescence patulent, paniculate, branches in upper part approximate or opposite, lateral branches exceeding central umbel. Basal leaves multiple, petioles up to 4.5 cm, flattened, sheath narrow; leaf blades 11–15 cm long 3–4 cm wide lanceolate of linear-lanceolate, bipinnate, primary segments sessile, rhombic in outline, coarsely toothed, cuneate at base; terminal lobes 4–7 mm long, obovate or lanceolate, cuneate at base, notched on top. Cauline leaves simplified, pinnate, with linear-lanceolate or lanceolate lobes 1–1.5 cm long; uppermost leaves with simple linear leaf blades. Central umbel slightly larger than lateral umbels, 7–9 cm ∅, 5–8-rayed; rays spaced, tiny, slightly unequal, 3.5–5 cm long, bracts missing. Umbellules with 13–15 flowers, peduncles slightly unequal and thickened, nearly orbicular, 2–3.5 mm long. Number of bracteoles 4–6, linear-lanceolate, in upper part narrowed, glabrous, herbaceous, green-brownish. Mericarps homomorphic ( Fig. 4 ), strongly dorsally compressed, 5.5– 6.5 (7) mm long, 2.5–3.5 mm wide, elongate-elliptic, only primary ribs present; ribs unequal, marginal ribs thickened, enlarged, dorsal ribs filiform, all ribs with straight, entire margins. Calyx teeth missing, carpophore bifurcated to base, stylopodia low conical, lobate, styles decurved, about 1 mm long; commissure broad; secretory ducts between ribs solitary, number of commissural secretory ducts 3–4, sometimes these ducts obscure; endosperm flat at commissural side.

Paratypes:  IRAN, Lorestan Province, 1 km N from Sepid Dasht , dry rocky slope, alt. 1000, 33.226269° N, 48.886078° E, 30 June 2019, Lyskov 34-IR-19 ( TARI) ; Lorestan Province: 4 km NEE from Sepid Dasht , dry rocks, alt. 1300, 33.226685° N, 48.919480° E, 30 June 2019, Lyskov 166-IR-19 ( MW barcode MW0595735) .

Etymology: —The specific epithet refers to a place where the new species was found, the rocky outcrops above the road.

Phenology: —Flowering probably in May and June; fruiting in June and July.

Distribution: —The species is only known from the type locality in Iran, Lorestan Province.

Figures

FIGURE 2. Dichoropetalum viarium holotype sheet 1 (MW0595738). Courtesy of the National Depository Bank of Live Systems, Moscow State University.

FIGURE 3. Dichoropetalum viarium holotype sheet 1 (MW0595736). Courtesy of the National Depository Bank of Live Systems, Moscow State University.

FIGURE 4. Mericarp of Dichoropetalum viarium: a—mericarp in dorsal view; b—mericarp structure: 1—exocarp, 2—mesocarp, 3— endosperm, 4—vascular bundle, 5—vitta, 6—mesocarp parenchyma with lignified pitted walls.

FIGURE 5. Dichoropetalum viarium in a habitat of the type locality.