Peucedanum chujaense K.Kim, S.H.Oh, C.S.Kim & C.W.Park, 2019

Kim, Kyeonghee, Kim, Chan-Soo, Oh, Sang-Hun & Park, Chong-Wook, 2019, A new species of Peucedanum (Apiaceae) from Korea, Phytotaxa 393 (1), pp. 75-83 : 76-79

Peucedanum chujaense K.Kim, S.H.Oh, C.S.Kim & C.W.Park , sp. nov. ( Figs 2 , 3 )

Type:― KOREA. Jeju Prov.: Jeju-shi, Chuja Islands , rocky cliffs along seashore, 2 m, 33° 55′ 50.8″N, 126° 19′ 45.3″E, 24 November 2014, C.- W. Park, C.- S. Kim, J. Kim, T. Y. Choi & K. Kim 1601 (holotype SNU!; isotypes KB!, SNU!, TI!, WFRC!) .

Diagnosis: Peucedanum chujaense is similar to P. litorale , but differs in having 2-pinnate leaves (vs. 1-pinnate leaves), conspicuous calyx teeth 0.4–1 mm long (vs. minute calyx teeth 0.1–0.3 mm long), 20–24 (vs. 10–18) flowers per umbellet, and seeds oblong (vs. semicircular) in cross section.

Herbs, perennial, hermaphroditic, (24–)35–75(–90) cm tall. Root a taproot, yellowish white, 15–30 × 0.8–1.5 cm. Rhizomes erect, 1.5–5 × 0.6–1 cm, woody. Stems erect, much branched, 6–9 mm in diam., longitudinally grooved, solid, glabrous, with fibrous remnants of basal leaves. Leaves basal and cauline, alternate, long-petiolate; petiole sheathing at base. Basal leaves 5–20, persistent; petiole (5.5–)7.5–10.5(–12.5) cm long; sheath purplish, cylindrical, 0.5–1.5 mm wide, margins scarious; blade ovate to triangular in outline, 1-or 2-pinnate, 6.3–10.5 × 4.5–8.7 cm, coriaceous, adaxial surface green, abaxial surface pale green, both surfaces glabrous, shiny; terminal leaflet ovate-rhombic or rhombic, 3-lobed, 2.5–3.4 × 2.5–4.2 cm, apex obtuse, base cuneate, margins crenate, sessile; lateral leaflets ovate-rhombic, irregularly lobed, 1.7–2 × 1–1.5 cm, apex obtuse, base cuneate, margins crenate, sessile; ultimate segments elliptic or obovate, 1.5–2 × 1–1.7 cm. Cauline leaves similar to basal leaves but smaller; petiole 3–7.2 cm long; blade 7–9 × 5.8– 6.2 cm, adaxial surface sometimes sparsely pubescent with unicellular hairs along midvein. Inflorescences terminal and lateral, with 6–20 compound umbels, more or less round-topped, 4.3–5.8 cm in diam.; umbellets hermaphroditic, 20–24-flowered, 0.7–1 cm in diam.; peduncle 3.8–5.2 cm long, sparsely pubescent with short simple unicellular hairs in upper part; rays (10–)16–18, spreading to ascending, 0.4–2.1 cm long, unequal in length, adaxial surface sparsely to densely pubescent with simple unicellular hairs; bracts 1–4, persistent or rarely caducous, lanceolate, entire, 4– 8 × 1.5–2 mm, apex acute, margins scarious, glabrous; pedicels 1–5 mm long, adaxial surface sparsely pubescent with simple unicellular hairs; bractlets 4–8, lanceolate to narrowly triangular, entire, 2–3.2 × 0.5–1 mm, apex acute, glabrous. Flowers bisexual, actinomorphic; calyx 5-toothed; calyx teeth narrowly triangular, 0.4–1 × 0.3–0.8 mm, adaxial surface glabrous, abaxial surface sparsely pubescent with simple unicellular hairs; petals 5, white, obovate, 1.2–1.5 × 1–1.3 mm, apex incurved, base cuneate, glabrous; stamens 5, alternating with petals; filaments filiform, 1.5–1.8 mm long; anthers 2-locular, purple; pollen grains monad, polar axis ( P) 20.3–23.3 ìm, equatorial axis ( E) 9.96–11.7 ìm, P / E = 1.74–2.34, isopolar symmetric, triangular in polar view, prolate in equatorial view, tricolporate, ornamentation rugulate; pistil 1, 2-carpellate; ovary inferior, syncarpous, 2-locular; stylopodium conical; styles 2, free, ascending, reflexed in fruit. Fruit a dry schizocarp composed of 2 mericarps, ellipsoid; carpophore 3.2–4.2 mm long, 2-cleft ca. 1/2 its length; mericarps dorsally compressed, 3.5–5 × 2–2.5 mm, glabrous; dorsal ribs 3, filiform, prominent, not winged; marginal ribs winged; wings 0.8–1 mm wide, scarious; secondary ribs absent; vittae 20–28, 3 or (4) per vallecula, 8–12 on commissure; commissure 2–2.5 mm wide. Seed narrowly oblong in cross section; face slightly concave.

Additional specimens examined (Paratypes): ― KOREA. Jeju Prov.: Jeju - shi, Chuja Islands , Shinyang-ri, 1 December 2010, J. Kim 31154, 31155 ( WFRC) ; same locality, 27 October 2011, J. Kim & C. W. Kang 33397 ( WFRC) ; same locality, 21 m, 33° 55′ 49.65″N, 126° 19′ 43.53″E, 24 November 2014, C.- W. Park et al. 1609, 1610, 1611, 1622, 1613 ( SNU) ; same locality, 19 m, 33° 55′ 49.75″N, 126° 19′ 42.75″E, C.- W. Park et al. 1616, 1619, 1636, 1637, 1638 ( SNU) ; same locality, 47 m, 33° 55′ 54.46″N, 126° 19′ 35.79″E, C.- W. Park et al. 1608, 1615 ; same locality, 133 m, 33° 55′ 54.97″N, 126° 19′ 17.64″E, C.- W. Park et al. 1623 ( SNU) ; same locality, 127 m, 33° 55′ 53.47″N, 126° 19′ 26.79″E, C.- W. Park et al. 1624, 1625, 1626, 1627, 1628, 1629, 1630, 1631 ( SNU) ; same locality, 124 m, 33° 54′ 01.48″N, 126° 18′ 58.95″E, C.- W. Park et al. 1632, 1633, 1634, 1635 ( SNU) .

Distribution and habitat:― Peucedanum chujaense is known only from the Chuja Islands located in the Jeju Strait of southern Korea. It occurs in open areas on rocky cliffs and hills near the seashore ( Fig. 1 ). Two populations were found on the South Island. One population was on open rocky cliffs along the seashore together with Lathyrus japonicus Willdenow (1802: 1092) ( Fabaceae ), Calystegia soldanella ( Linnaeus 1753: 159) Brown (1810: 484) ( Convolvulaceae ), and Rosa wichuraiana Crépin (1886: 189) ( Rosaceae ), and the other was on slopes of hills associated with Miscanthus sinensis Andersson (1855: 166) ( Poaceae ) under Pinus thunbergii Parlatore (1868: 388) ( Pinaceae ). Each population was composed of about 100 individuals. No additional localities of P. chujaense were found outside of the type locality while examining specimens from several herbaria and during field work. The new species is considered endangered ( IUCN 2017; EN B2a) because of its limited occurrence on the Chuja Islands off the north coast of Jeju Island, Korea.

Phenology:―Flowering September to October. Fruiting October to November.

Etymology:―The specific epithet ‘ chujaense ’ refers to the Chuja Islands, where the type specimen was collected.

Discussion:― Peucedanum chujaense belongs to P. sect. Oreoselinum in having elliptic ultimate segments of leaves with crenate margins, distinct bracts and bractlets, white obovate petals, distinct calyx teeth, and narrow marginal wings of mericarp. Peucedanum sect. Oreoselinum comprises about 10 species distributed in Asia and Europe ( Thellung 1926, Schishkin 1951, Shan and Sheh 1992).

Among the members of P. sect. Oreoselinum, Peucedanum chujaense is morphologically most similar to P. litorale , which is distributed in northern Korea and Far East Russia, in having solid stems with fibrous remnants of the basal leaves, stout taproot and rhizomes, shiny, coriaceous leaves, cylindrical leaf sheaths, and ellipsoid mericarps with 20–28 vittae. Peucedanum chujaense is, however, distinct from P. litorale in having 2-pinnate leaves, conspicuous calyx teeth, 20–24 flowers per umbellet, and seeds oblong in cross section ( Fig. 4 ; Table 1). In addition, P. chujaense has glabrous (vs. sparsely pubescent) leaves and broader bractlets (0.5–1 mm vs. 0.2–0.3 mm).

Peucedanum chujaense is also distinct from the other species of Peucedanum in Korea. It is clearly distinguished from P. terebinthaceum var. terebinthaceum , P. terebinthaceum var. deltoideum , P. paishanense and P. elegans of P. sect. Selinoides by the number of vittae per mericarp; P. chujaense has 20–28 vittae per mericarp, whereas the latter four taxa have six. It differs from P. hakuunense , P. coreanum of P. sect. Thysselinum , and P. japonicum of P. sect. Palimbioides in having 2-pinnate leaves ( Fig. 4 ).

Figures

FIGURE 1. Distribution of Peucedanum chujaense.

FIGURE 2. Photographs of Peucedanum chujaense in their habitat. A. Habit. B. Rootstock. C. Leaf. D. Compound umbel. E. Fruit.

FIGURE 3. Illustration of Peucedanum chujaense. A. Habit. B. Flower. C. Umbellet. D. Terminal leaflet. E. Mericarp (dorsal view). F. Mericarp (cross section) (A–F. Park et al. 1601).

FIGURE 4. Variation in shape and size of basal leaves of Peucedanum species in Korea.A.P.chujaense; B.P.litorale; C. P.terebinthaceum var. terebinthaceum; D. P. terebinthaceum var. deltoideum; E. P. elegans; F. P. coreanum; G. P. paishanense; H. P. hakuusanense; I. P. japonicum var. japonicum (A. Park et al. 1601; B. Park et al. 157; C. Kim 1422; D. Choi 570; E. Park et al. 120610; F. Nakai 5720; G. Oh et al. 90; H. Kim 1432; I. Park 150702). Scale bar: 3 cm.