Two new endemic species, Peucedanum miroense and P. tongkangense (Apiaceae), from Korea Author Kim, Kyeonghee https://orcid.org/0000-0001-6219-2229 Plant Resources Division, National Institute of Biological Resources, Incheon 22689, Republic of Korea Author Suh, Hwa-Jung https://orcid.org/0000-0003-2528-425X Department of Biology, Daejeon University, Daejeon 34520, Republic of Korea Author Song, Jun-Ho https://orcid.org/0000-0002-8987-4710 Herbal Medicine Resources Research Center, Korea Institute of Oriental Medicine, Naju 58245, Republic of Korea & Department of Biology, Chungbuk National University, Cheongju 28644, Republic of Korea jhsong@chungbuk.ac.kr text PhytoKeys 2022 2022-09-29 210 35 52 http://dx.doi.org/10.3897/phytokeys.210.86067 journal article http://dx.doi.org/10.3897/phytokeys.210.86067 1314-2003-210-35 34AFE87E862957999ECADBC7D32540C8 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 !] . 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, KIOM2021-646-2 ). 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 ). Table 1. Comparison of major morphological characteristics of Peucedanum miroense , P. tongkangense , and their close relatives P. hakuunense and P. elegans .

-	P. miroense	P. tongkangense	P. hakuunense *	P. elegans *
Habitat	crevices of rocks on mountain summits	open areas on rocky cliffs along the river	grassy places on mountain summits	mountain slopes
Height (cm)	37-50	60-120	30-75	60-90
Stems
Pith	solid	solid	solid	hollow
Branch	branched	much branched	much branched	simple or branched in upper part
Basal leaves
Division	2-pinnate	3-pinnate	2-ternate	3-pinnate
Persistence	usually deciduous	usually deciduous	persistent	persistent
Outline of blade	ovate to triangular	elliptic to rhombic	triangular to pentagonal	ovate or ovate-oblong
Central/terminal leaflet division	1- or 2-pinnatisect	2-pinnatisect	2-pinnatisect	1-pinnatisect
Central/terminal leaflet shape	triangular or ovate-rhombic	triangular or ovate-rhombic	ovate or rhombic	ovate-rhombic
Ultimate segments shape	narrowly oblong-lanceolate to linear	narrowly oblong-lanceolate to linear	narrowly lanceolate	linear
Ultimate segments apex	acute	acute	acute	cuspidate with spine 1-1.5 mm long
Cauline leaves
Division	1-pinnatisect	1- or 2-pinnatisect	deeply 3-lobed	entire or 3-lobed
Uppermost one shape	ovate to rhombic	ovate to rhombic	ovate	linear or lanceolate
Inflorescences
No. of flowers per umbellet	16-23	15-25	15-20	20-24
No. of rays	12-16	16-18	10-20	15-25
No. of bracts	1 or 2	1	usually absent, rarely 1 or 2	5-7
No. of bractlets	6-10	5-6	6 or 8, rarely 9	6-9
Flowers
Petal color	white	white	white or pinkish	white or pinkish white
Petal shape	obcordate	obcordate	oblong to obovate	obovate-orbicular
Petal size (mm)	0.9-1.2 x 0.7-1.2	0.7-1.3 x 0.9-1.6	approximately 1 x 0.8	0.5-1 x 0.7-1
Anther color	purple	yellowish white	pale yellow	pale yellow
Anther size (mm)	0.3-0.5 x 0.4-0.5	0.5-1.1 x 0.8-1.2	0.2-0.3 x ca. 0.2	0.3-0.4 x 0.2-0.3
Fruit
Carpophore length (mm)	3.4-4.5	2.1-2.4	2.5-4.5	2.9-3.8
Mericarp size (mm)	3.7-5 x 2.4-2.7	3.8-4.4 x 1.5-2	3.7-4 x 2.3-2.5	3-4 x 2-3
Pubescence on dorsal side	moderately to densely pubescent with short simple unicellular hairs	subglabrous to sparsely tuberculate	sparsely tuberculate†	moderately to densely pubescent with short simple unicellular hairs†
Marginal wings width (mm)	0.2-0.7	0.2-0.3	approximately 0.5	0.5-0.8
No. of vittae	8 or 9	13-16	18-28	6
No. of vittae per vallecula / on commissure	1 or (2) / 4	3 / 4	3 or 4 / 6-12	1 / 2

* Refer to the Park et al. (2017) , Flora of Korea, Vol. 5c. Rosidae : Rhamnaceae to Apiaceae . † Newly updated description of mericarp surface in the present study. Description. Herbs, perennial, hermaphroditic, 37-50 cm tall. Root a taproot, whitish to pale yellow, elongated, thickened, approximately 20 x 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 x 5-7.5 mm, margins scarious, glabrous; blade ovate to triangular in outline, 6.5-11.5 x 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 x 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 x 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 x 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 x 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 x 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 x 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 x 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 x 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 x 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 x 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 ).