Allium dumebuchum H.J.Choi, 2021

Jang, Ju Eun, Park, Jong-Soo, Jung, Ji-Young, Kim, Dong-Kap, Yang, Sungyu & Choi, Hyeok Jae, 2021, Notes on Allium section Rhizirideum (Amaryllidaceae) in South Korea and northeastern China: with a new species from Ulleungdo Island, PhytoKeys 176, pp. 1-19 : 1

publication ID

https://dx.doi.org/10.3897/phytokeys.176.63378

persistent identifier

https://treatment.plazi.org/id/33B1FC43-6CF2-5B81-AFB3-A0D18D3ABDC7

treatment provided by

PhytoKeys by Pensoft

scientific name

Allium dumebuchum H.J.Choi
status

sp. nov.

Allium dumebuchum H.J.Choi sp. nov. Figs 1A-E View Figure 1 , 4 View Figure 4

Diagnosis.

This new species is morphologically similar to A. senescens due to its habits. However, it is clearly distinguished from A. senescens , particularly by its rhomboid scapes in cross-secion (vs. subterete), light purple perianth color (vs. pale purple), entire and narrowly triangular inner filaments (vs. sometimes toothed and broadened for ca. 1/2 in length), and flowering season from late September (vs. from July).

Type.

South Korea. Gyeongbuk: Ulleung-gun, Namyang , 37.46702N 130.83665E, elev. 11m, 8 Oct 2020 [fl], H.J.Choi 201008-001 * (Holotype: KH; Isotypes: CWNU, KB, KIOM) GoogleMaps .

Description.

Herbs hermaphroditic. Rhizomes clearly elongated, thick and branched, oblique to horizontal, 14.8-55.4 mm long. Bulbs clustered, cylindrically conical, 9.6-15 mm in diam.; tunics membranous, smooth, white. Leaves 4-9; sheaths slightly exposed above ground, 4-7.8 cm long; blades ascending, slightly tortuous, linear, flat and solid in cross-section, flesh, 19.5-38 cm × 3.8-13 mm, apex obtuse to rounded. Scapes rhomboid and solid in cross-section, drooping before flowering, 23.4-49 cm × 2.5-5.6 mm. Inflorescences umbellate, subglobose, 23-41.5 × 37-53 mm, 48-113 flowered; pedicels terete, subequal in length, 9.8-11.2mm long; bracts 3.2-5 mm long. Flowers bisexual; perianth semi-radially spreading, light purple; inner tepals longer than outer ones, elliptical, apex obtuse, 5.2-7.2 × 3.4-4.5 mm; outer tepals ovately elliptical, apex obtuse, 4.8-6.1 × 2.1-3.7 mm; filaments exserted, 6.2-8.4 mm long, margin entire; inner filaments narrowly triangular; anthers elliptical, reddish, 2.2-2.5 × 0.9-1.1 mm long; ovary obovoid, reddish, 3.2-3.8 × 3.2-3.7 mm, ovules 2 per locule; style terete, exserted; stigma smooth. Capsules cordiform, trigonous, 5.4-5.6 × 5.6-5.8 mm. Seeds oval, semi-circular in cross-section, 3.7-3.8 × 2.4-2.6 mm.

Phenology.

Flowering from late September to October; fruiting from late October to November.

Distribution and habitat.

Endemic to South Korea (Ulleung-do Island; Fig. 5 View Figure 5 ). Open slope of rocky area.

Etymology.

The specific epithet, " Allium dumebuchum " is based on the name of traditional vegetable for this species in South Korea.

Vernacular name.

The Korean name of the new species is "Du-me-bu-chu ( 두메부추)”.

Conservation status.

The new species is endemic to Ulleungdo Island, and usually grows along the coast at altitudes of -23-171m a.s.l. From the present study, the extent of occurrence (EOO) and the area of occupancy (AOO) of this species have been calculated to be 47,683 km2 and 48 km2, respectively. Currently, there is no information on population size and trend data. However, this new species is only known from a single location of Ulleungdo Island, and mainly occurs on the coast which is critically threatened by extensive construction and repair of coastal roads ( Choi et al. 2012a). Therefore, decline in habitat area, habitat extent, and quality of habitat for this species have been continuously observed. Thus, Allium dumebuchum should be considered as Critically Endangered [CR B1ab(iii)] according to the IUCN Red List categories and criteria ( IUCN 2021).

Notes.

Allium dumebuchum , occurring in Ulleungdo Island of South Korea, has usually been misidentified as A. senescens ( Choi and Oh 2010; Choi and Oh 2011). However, this new species remarkably distinguished itself from its related species of section Allium senescens Rhizirideum (e.g., A. spirale , A. spurium , A. minus , and A. senescens ) in having clearly bigger floral parts that bloom from late September (Table 3 View Table 3 ; Fig. 1 View Figure 1 ). The PCA results based on quantitative floral characters of five related species in section Allium senescens Rhizirideum clearly identified A. dumebuchum from others (Fig. 2 View Figure 2 ). This new species is a tetraploid (2 n = 4 x = 32) taxon along with A. senescens , and A. minus is a diploid (2 n = 2 x = 16), whereas A. spirale and A. spurium showed polyploidy (Table 3 View Table 3 ; Fig. 3 View Figure 3 ). Moreover, molecular phylogenetic analyses using chloroplast markers (ndhJ - trnF, trnH - psbA, psbD - trnT, and psbJ - petA) also clearly indicate that A. dumebuchum is genetically distinct from other species of section Allium dumebuchum Rhizirideum (Fig. 6 View Figure 6 ).

Additional specimens examined

(Paratypes). South Korea. Gyeonggbuk: Ulleungdo Isl. , Namyang valley , 11 Sep. 2006, ParkSH 61820 (KH); Ulleungdo Isl. , Tonggumi, 26 Sep. 1995, S-4255 (KH); Ulleungdo Isl. , Namyang, 15 Aug. 2009, Ulleung68-090815-002 (KH); Ulleungdo Isl. , Namyang, 22 Aug. 2011, JMC12750 View Materials (KH); Ulleungdo Isl. , Namyang, 29 Oct. 2013, 2013KBV091 (KH); Ulleungdo Isl. , Namyang, 5 Sep. 2003, SCHONG2003100 (KH); Ulleungdo Isl. , Chusan, 2 Sep. 2009, JMC11306 View Materials (KH); Ulleungdo Isl. , Dodong, 18 Sep. 2007, H.J.Choi 070001 (KH); Ulleungdo Isl. , Sadong, 23 Aug. 2005, 1073 (KB); Ulleungdo Isl. , Sadong, 23 Aug. 2005, KH1283 (KB); Ulleungdo Isl. , Nari, 25 Sep. 2001, J.S.Kim s.n. (KB); Ulleungdo Isl. , Hyeonpo, 4 Oct. 2011, 19-1 (KB); Ulleungdo Isl. , Nari, 17 Sep. 2019, H.J.Choi 190917-01 (CWNU); Ulleungdo Isl. , Namyang, 8 Oct. 2020, H.J.Choi 201008-002 (CWNU); Ulleungdo Isl. , Namyang, 8 Oct. 2020, H.J.Choi 201008-003 (CWNU); Ulleungdo Isl. , Sadong, 12 Oct. 2005, NAPI-20101161 (KB); Ulleungdo Isl. , 11 Jul. 2013, H.J.Choi s.n. (KB); Ulleungdo Isl. , 23 Aug. 2005, 1406 (KB); Ulleungdo Isl., 3 Sep. 2008, SK2008-019-096 (KB); Ulleungdo Isl., 15 Oct. 2009, ksh84 (KB) .