Peucedanum miroense K. Kim, H.J.Suh & J.H.Song, 2022

Kim, Kyeonghee, Suh, Hwa-Jung & Song, Jun-Ho, 2022, Two new endemic species, Peucedanum miroense and P. tongkangense (Apiaceae), from Korea, PhytoKeys 210, pp. 35-52 : 35

Peucedanum miroense K. Kim, H.J.Suh & J.H.Song sp. nov.

Figs 1 , 2 , 6A

Type.

Korea. Gangwon Province: Samcheok-si, Miro-myeon, Naemiro-ri , Swinŭm-san, crevices of rocks on mountain summits, 37°26'37.7"N, 129°01'49.4"E, alt. 540 m, 7 September 2021, J.H.Song & S. Yang, KIOM-2021-646-1 [Holotype: KIOM! (Fig. 6A ); Isotype KB!] .

Diagnosis.

Peucedanum miroense is similar to P. elegans but differs in its height at anthesis 37-50 cm tall (vs. 60-90 cm) and number of vittae, 8 or 9 vittae (vs. 6), 1 or (2) per vallecula (vs. 1 per vallecula), and 4 on commissure (2 on commissure). Peucedanum miroense is similar to P. hakuunense in ultimate leaf segments but has 2- or 3-pinnate leaves (vs. 1- or 2-ternate leaves) (Table 1 ).

Description.

Herbs, perennial, hermaphroditic, 37-50 cm tall. Root a taproot, whitish to pale yellow, elongated, thickened, approximately 20 × 0.6-1.2 cm. Rhizomes erect or ascending, yellowish white, cylindrical, 0.3-1 cm in diameter, woody. Stems erect, purplish below middle, purplish green apically, branched, 4-7 mm in diameter, terete, longitudinally grooved, solid, glabrous, with fibrous remnants of basal leaves. Leaves basal and cauline, alternate, pinnately compound, petiolate, petiole sheathing at base; stipules absent. Basal leaves many, 2-pinnate, usually deciduous; petiole 5.6-9.5 cm long, glabrous; sheath purplish or purplish green, cylindrical, not inflated, 1.1-1.8 cm × 5-7.5 mm, margins scarious, glabrous; blade ovate to triangular in outline, 6.5-11.5 × 7.3-10.6 cm, both surfaces green, glabrous; petiolule of terminal leaflet (0.8-)1.7(-3.5) cm long; terminal leaflet triangular or ovate-rhombic, 1- or 2-pinnatisect, 1.5-2.2 × 1.5-2.6 cm, apex acute, base cuneate, margins entire; petiolule of basal lateral leaflets 0.7-2.7 cm long; lateral leaflets elliptic-ovate to ovate, 1- or 2-pinnatisect, 1.8-5 × 1.3-3.7 cm, apex acute, base cuneate, margins entire, uppermost ones sessile; ultimate segments narrowly oblong-lanceolate to linear, 0.5-1.2 cm × 1.8-3.5 mm. Cauline leaves similar to basal ones and becoming smaller upward; petiole of lower cauline leaves (1.5-)4.8-8 cm long, reduced upward, glabrous; blade elliptic to ovate in outline; uppermost cauline leaves ovate to rhombic, 1-pinnatisect, 0.6-1 × 0.5-1.2 cm, sessile. Inflorescences terminal and lateral, with 2-10 compound umbels, more or less flat-topped, 6.5-7 cm in diameter; umbellets hermaphroditic, 16- to 23-flowered, 1.1-1.5 cm in diameter; peduncle 2.5-6 cm long, sparsely pubescent with short simple unicellular hairs, uppermost part densely pubescent; rays 12-16, spreading to ascending, 1-2.7 cm long, unequal in length, adaxial surface sparsely pubescent with short simple unicellular hairs; bracts 1 or 2, persistent or sometimes caducous, lanceolate, entire, 0.9-1.2 cm × 1-1.8 mm, apex acute, margins scarious, glabrous; pedicels 1.5-7 mm long, adaxial surface sparsely pubescent with simple unicellular hairs; bractlets 6-10, persistent, linear, entire, 2.6-6.7 × 0.4-0.6 mm, apex acute, glabrous. Flowers bisexual, actinomorphic, 1.8-2.1 mm in diameter; calyx 5-toothed; calyx teeth minute, narrowly triangular, 0.2-0.5 × 0.1-0.3 mm, adaxial surface glabrous, abaxial surface sparsely pubescent with short conical simple unicellular hairs; petals 5, white, obcordate, 0.9-1.2 × 0.7-1.2 mm, apex incurved, base cuneate to caudate, with greenish yellow line on abaxial surface, glabrous; stamens 5, alternating with petals, with purplish dots; filaments filiform, 1.2-2 mm long; anthers 2-locular, purple, introrse, versatile, dehiscing longitudinally, subglobose, 0.3-0.5 × 0.4-0.5 mm; pistil 1, 2-carpellate; ovary inferior, syncarpous, 2-locular, moderately to densely pubescent with short simple unicellular hairs; stylopodium conical; styles 2, free, ascending, 0.2-0.5 mm at anthesis, 1.0-1.5 mm in fruit, swollen at base to form a stylopodium, reflexed in fruit; ovule 1 per locule, anatropous, pendulous. Fruit a dry schizocarp composed of 2 mericarps, pale brown to brown at maturity, oblong; carpophore 3.4-4.5 mm long, 2-cleft; mericarps splitting apart at maturity, oblong, dorsally compressed, 3.7-5.0 × 2.4-2.7 mm, moderately to densely pubescent with short simple unicellular hairs on dorsal surface, glabrous on commissural surface; dorsal ribs 3, prominent, not winged; marginal ribs 2, slightly winged; wings 0.2-0.7 mm wide, scarious; secondary ribs absent; vittae (oil tubes) 8 or 9, 1 or (2) per vallecula and 4 on commissure; commissure 1.7-3.6 mm wide. Seed 1 per mericarp; narrowly oblong in cross-section; face plane.

Phenology.

Flowering September to October. Fruiting October to November.

Etymology.

The specific epithet ' Peucedanum miroense ' refers to Miro-myeon, Samcheok-si, where the type specimen was collected.

Vernacular name.

Mi-ro-gi-reum-na-mul.

Distribution and ecology.

Peucedanum miroense is restricted to only two populations on the summits of Swinŭm-san and Duta-san at Miro-myeon, Samcheok-si, Gangwon Province, South Korea. The two populations are connected to each other. The plants occur in rocky areas at the top of the mountains at an elevation of 540-680 m (Fig. 5 ). One population, at the type locality on Swinŭm-san, was growing with Allium thunbergii G. Don ( Amaryllidaceae ), Dendranthema boreale (Makino) Y. Ling ex Kitam. ( Asteraceae ), Fraxinus sieboldiana Blume ( Oleaceae ), Lespedeza bicolor Turcz., L. maximowiczii C.K. Schneid. ( Fabaceae ), Peucedanum terebinthaceum (Fischer ex Trevir.) Turcz. ( Apiaceae ), Pinus densiflora Siebold & Zucc. ( Pinaceae ), Quercus mongolica Fisch. ex Turcz ( Fagaceae ), Rhododendron mucronulatum Turcz. ( Ericaceae ), Sedum polytrichoides Hemsl. ( Crassulaceae ), and Spodiopogon sibiricus Trin. ( Poaceae ). The other population of P. miroense on Duta-san was growing with Aconogonon microcarpum (Kitag.) H. Hara ( Polygonaceae ), Chrysanthemum zawadskii Herbich ( Asteraceae ), and Geranium koreanum Kom. ( Geraniaceae ). Each population of P. miroense comprised approximately 120 individuals.

Additional specimens examined (Paratypes).

Korea. Gangwon Province: Samcheok-si, Miro-myeon, Naemiro-ri , Swinŭm-san, 37°26'46.5"N, 129°01'41.0"E, alt. 535 m, 12 October 2014, K. Kim & H.-J. Suh, KK#4 (SNU) .

Proposed IUCN conservation status.

After conducting fieldwork throughout the country and examining specimens from several domestic herbaria, we found out that Peucedanum miroense is known only from Miro-myeon, Gangwon. Therefore, according to the IUCN criteria, P. miroense is classified as endangered ( IUCN 2022; EN D) because the known number of individuals occurring at Swinŭm-san and Duta-san in Gangwon Province, South Korea, is less than 250.

Taxonomic notes.

Peucedanum miroense is morphologically similar to P. elegans and P. hakuunense among species with linear ultimate leaf segments. Peucedanum miroense is clearly distinguishable from P. elegans , which is restricted to mountain slopes in North Korea, by the shape of the leaf apex, the number of bracts, pubescence of the mericarp, and the number of vittae per mericarp (non-overlapping character states). Peucedanum miroense has an acute leaf apex, 1 or 2 bracts, moderate to dense pubescence with short simple unicellular hairs on the dorsal surface of the mericarps, and 8 or 9 vittae [1 or (2) per vallecula and 4 per commissure] whereas P. elegans has spine-tipped ultimate leaf segments, 5-7 bracts, glabrous mericarps, and 6 vittae (1 per vallecula and 2 per commissure) (Table 1 ).

Additionally, P. miroense is easily distinguishable from P. hakuunense , which is only in the southern part of South Korea, on the basis of its 2-pinnate leaves, obcordate petals, purple anthers, 8 or 9 vittae [1 or (2) per vallecula and 4 per commissure]; P. hakuunense has 3-ternate leaves, persistent basal leaves, oblong to obovate petals, and 18-28 vittae (3 or 4 per vallecula and 6-12 per commissure) (Table 1 ).

The natural habitat of P. miroense on Swinŭm-san and Duta-san in Gangwon Province is one of the major limestone areas in Korea, with sedimentary rock outcrops consisting of calcium carbonate. Peucedanum miroense can be considered a calciphile and added to the limestone flora of Korea ( Kim et al. 2021).

Figures

Figure 1. Photographs of Peucedanum miroense K. Kim, H. J. Suh & J. H. Song A-C habitat D basal leaves E cauline leaf F sheath G compound umbel (early flowering stage) H compound umbel (mature flowering stage) I umbellet (after anthesis) J bractlets K rays L flowers M calyx teeth and stylopodium (mature fruiting stage) N dorsal side of mericarp O commissural side of mericarp P transverse plane of mericarp. cv, commissure vittae; dr, dorsal ribs; dv, vallecula vittae; mr, marginal ribs; tr, trichomes; vb, vascular bundles.

Figure 2. Peucedanum miroense K. Kim, H. J. Suh & J. H. Song A habit B flower C umbellet D basal cauline leaf E mericarp (dorsal side) F mericarp (commissural side) G mericarp (cross-section) (A-F J. H. Song & S. Yang, KIOM 2021 - 646 - 2).

Figure 5. Distribution of Peucedanum miroense and P. tongkangense = gray ellipse. P. miroense = black circle. P. tongkangense = black squares. Blue lines: rivers.

Figure 6. Holotype of A Peucedanum miroense K. Kim, H. J. Suh & J. H. Song (J. H. Song & S. Yang, KIOM- 2021 - 646 - 1) and B P. tongkangense K. Kim, H. J. Suh & J. H. Song (J. H. Song & S. Yang, KIOM- 2021 - 802 - 1).