taxonomic revision of oxalis subsect. (oxalidaceae)

cally, have caused frequent misidentifications in subsect. Oxalis, especially of the species in East-ern Asia (Liu & Watson 2008).

To reassess the taxonomy of subsect. Oxalis, we compared the morphology, genome size and molecular phylogeny of samples of Oxalis from a wide geographical area (Aoki et al. 2017, 2018). In the phylogenetic tree (Fig. 1), some taxa were not monophyletic.

In our studies, Oxalis griffithii var. griffithii in Japan (including the indistinguishable O. aceto-sella var. longicapsula) formed a clade (Clade C) independent of those in China (Clade A). Oxalis acetosella var. longicapsula was also in Clade C, and O. griffithii var. kantoensis was placed in Clade D. Most Japanese plants of O. acetosella var. acetosella, formed a clade with O. acetosella var. acetosella in China and Europe (Clade B), but a few Japanese plants were in Clade D. Addi-tionally, the American O. acetosella var. aceto-sella occupied a unique phylogenetic position (as

The taxonomic history of Oxalis L. sect. Ox-alis subsect. Oxalis based on Hara (1954, 1955), Terao (1979), Huang & Liu (2003), Huang et al. (1998), Lourteig (2000), Amano (2001), and Liu & Watson (2008) was summarized previously (see Table 1 in Aoki et al. 2017). In the Flora of Japan (Amano 2001), this section was treated as sect. Acetosellae (Reiche 1894) R. Knuth 1914, but it should have been sect. Oxalis, because this section includes O. acetosella L., the type of the genus Oxalis (Turland et al. 2018, International Code of Nomenclature Art. 22.1). Lourteig (2000) treated all taxa in the subsection and recognized O. magellanica G. Forst. in Oceania and South America, O. griffithii Edgew. & Hook.f., O. obtri-angulata Maxim. and O. leucolepis Diels in the Far East and eastern Asia, O. oregana Nutt. ex Torr. & A. Gray and O. trilliifolia Hook. in North America and the widespread O. acetosella. Leaf-let shape and the spacing of the petioles on the rhizome, which are difficult to express numeri-

Acta Phytotax. Geobot. 70 (3): 159–172 (2019)

Taxonomic Revision of Oxalis subsect. Oxalis (Oxalidaceae)

SatoShi aoki1,*, tetSuo ohi-toma2,† and Jin murata2

1Graduate School of Science, The University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo 153-8902, Japan. *[email protected] (author for correspondence); 2Botanical Gardens, Graduate School of Science,

The University of Tokyo, 3-7-1 Hakusan, Bunkyo-ku, Tokyo 112-0001, Japan. † Present address: Nature Fieldwork Center, Okayama University of Science, 1-1 Ridaicho, Kita-ku,

Okayama 700-0005, Japan

The classification of Oxalis subsect. Oxalis (Oxalidaceae) is revised based on phylogenetic, cyto-logical and morphological evidence. For the f lora of Japan, one new species and one new variety are described, and five new combinations are proposed. The new species, O. nipponica, resembles O. griffithii, but is distinguished by its unique phylogeny, larger genome and distribution. Oxalis nipponica is subdivided into two subspecies, nipponica and kantoensis based on phylogeny and fruit length. Subsp. kantoensis is further divided into two varieties based on ploidy level, length of the fruit and seeds and habitat. While diploids correspond to var. kantoensis, the tetraploids cor-respond to the newly described var. alpigena. Variety alpigena resembles O. acetosella and has been confused with it. Fourteen taxa, including one hybrid, are recognized in subsect. Oxalis.

Key words: new species, new variety, Oxalidaceae, Oxalis nipponica subsp. kantoensis var. alpigena

doi: 10.18942/apg.201906ISSN 1346-7565

160 Vol. 70Acta Phytotax. Geobot.

Oxalis montana in Fig. 1). The comparison be-tween the previous classification (Lourteig 2000, Amano 2001) and the results from our analysis is summarized in Table 1.

Our cytological analysis showed differences in genome size among Clades A–D, but Clades C and D had genomes of nearly the same size. Clades C and D also had genomes of two sizes, which corresponded to the diploids and tetra-ploids reported by Terao (1979).

Besides examining specimens, we measured the length of the capsule, the length to width ratio of the capsules and the length of seeds among our samples. We then compared the measurements. From the data gathered from samples of O. griffithii subsp. griffithii, we could not distin-guish between the samples from China (Clade A) and Japan (Clade C). While diploids and tetra-ploids in Clade C were indistinguishable, capsule length and seed length were informative for dis-tinguishing between diploids and tetraploids in Clade D. Consequently, we decided to revise sub-section Oxalis. In this revision, we excluded O. magellanica, because it was located phylogeneti-cally outside the outgroup in our phylogenetic analysis (Aoki et al. 2017). We kept the descrip-tion of North American taxa simple, because we examined few specimens in our previous studies (Aoki et al. 2017, 2018).

Oxalis japonica Franch. & Sav. has been con-sidered to be a Japanese endemic distinct from O. griffithii (cf. Makino 1908, Hara 1954), probably based on the description and the Japanese name used in the original study. Hara (1955), however, determined the holotype, Savatier 2816 (P, P00724040) of O. japonica, to be O. martiana Zucc., which had been introduced to Japan from South America. Hara (1955) identified the Japa-nese plants that had been treated as O. japonica or O. acetosella subsp. japonica (Franch. & Sav.) H. Hara as O. griffithii. Huang et al. (1998) ac-cepted O. acetosella subsp. japonica and synony-mized O. obtriangulata under it without consid-ering Hara’s (1955) treatment. In addition, they (Huang et al., 1998) did not recognize O. aceto-sella subsp. griffithii as occurring in Japan. In this study, we follow the treatment of Hara (1955).

In the present taxonomic treatment, we made species correspond to the confident clades. Intra-specific taxa were assigned based on cytological or minor phylogenetic differences accompanied by their ecological and/or morphological differ-ences. By minor phylogenetic differences, we mean monophyly with low confidence or mono-typic lineages that render a species paraphyletic or polyphyletic if they are considered as species. We examined specimens in the herbaria of Kyoto University (KYO), Tokyo Metropolitan Univer-sity (MAK), Makino Botanical Garden (MBK), National Taiwan University (TAI), Hokkaido University Museum (SAPS), and the University of Tokyo (TI). We also consulted digital images of specimens at the herbaria BR, E, G-DC, GH, HPSU, ID, K, LINN, M, P, PE, SOC, SRP, TNS, US and WTU. The herbarium acronyms follow Thiers (2018).

From our results, we recognize two new cryp-tic taxa. We treated the Japanese plants previous-ly identified as O. griffithii var. griffithii as a new species, O. nipponica subsp. nipponica. Our treatment is based on differences in genome size and phylogenetic position.

The second unrecognized cryptic taxon cor-responds to tetraploids of O. griffithii var. kan-toensis (Terao) T. Shimizu. This cryptic taxon was previously treated as tetraploids of O. aceto-sella by Terao (1979). In a previous study (Aoki et al. 2017), we determined its phylogenetic position and ploidy level. Considering its characteristic habitat and distribution, we now chose to treat this tetraploid as a new variety distinct from var. kantoensis and from O. acetosella, despite the difficulty in separating them based on morpholo-gy. The diploid plant previously identified as O. griffithii var. kantoensis is now treated as O. nip-ponica subsp. kantoensis var. kantoensis, and the cryptic tetraploid is treated as O. nipponica sub-sp. kantoensis var. alpigena. We also treat O. wulingensis from China, O. acetosella subsp. griffithii var. formosana from Taiwan, and O. tai-monii from Taiwan as subspecies of O. griffithii. We treated them as subspecies, since all of them were included in the same clade as O. griffithii (Clade A), but did not share identical sequences

October 2019 161aoki & al. – Taxonomic Revision of subsect. Oxalis

with Oxalis griffithii subsp. griffithii, and they exhibited clear morphological differences from subsp. griffithii. We also recognize O. montana as distinct from O. acetosella based on its phyloge-netic position.

Our revision recognizes six taxa in Japan, in-

cluding one hybrid, in subsect. Oxalis: O. aceto-sella, O. obtriangulata, O. nipponica subsp. nip-ponica, O. nipponica subsp. kantoensis var. kan-toensis, O. nipponica subsp. kantoensis var. alpi-gena, and O. acetosella × O. nipponica.

Fig. 1. Abridged phylogeny of Oxalis subsect. Oxalis based on nuclear ribosomal internal transcribed spacer (ITS) and Bayes-ian methods. Numbers near branches indicate posterior probabilities and bootstrap values by maximum likelihood and maximum parsimony methods. Hyphens indicate branches that did not appear in analysis; branches without numbers are monotypic branches based on a single sequence. For details, see Aoki et al. (2018).

table 1. Comparison between previous taxonomy (Lourteig 2000, Amano 2001) and taxonomy proposed here for confusing taxa in subsect. Oxalis. Proposed taxonomy shows scientific names suggested in this article and their corresponding phy-logenetic position as shown in Fig. 1 and ploidy levels for taxa in Clade D.

Previously recognized taxa Proposed taxa

O. griffithii var. griffithiiO. griffithii (Clade A)

O. nipponica subsp. nipponica (Clade C)

O. griffithii var. kantoensis (diploid) O. nipponica subsp. kantoensis var. kantoensis (Clade D, diploid)

O. acetosella (Clade B, diploid)

O. acetosella var. acetosella (diploid, tetraploid) O. montana

O. nipponica subsp. kantoensis var. alpigena (Clade D, tetraploid)

O. acetosella var. longicapsula O. nipponica subsp. nipponica (Clade C)


1. Oxalis acetosella L., Sp. Pl. 1: 433. 1753. — Type: No information on the specimen [lecto- LINN 600.7 designated by Nasir (1971); digital image!].

= Oxalis acetosella L. var. caerulea DC., Pro-dr. 1: 700. 1824. – Type: Not found.

= O. acetosella L. var. lilacina Lange., Haandb. Danske fl. 395. 1851. – Type: Not desig-nated.

= O. acetosella L. var. purpurea Lej., Fl. Spa. 307, 337. 1813. – Type: Not designated.

= O. acetosella L. var. purpurascens H. Mart., Prodr. fl. mosq. 81. 1817. Type: Belgium, A. Lejeune s.n. (lecto- BR 0000012172368 digital image!).

= O. acetosella L. var. rosea Peterm. in Fl. Lips. Excurs. 506. 1838. – Type: Not designated.

= O. acetosella L. var. subpurpurascente DC., Prodr. 1: 700. 1824. – Type: Not found.

= O. acetosella L. var. vegeta Tatew. in Trans. Sapporo Nat. Hist. Soc. 16: 86. 1940. – Type: Ja-

pan, Hokkaido: Chatsu, Isl. Okushiri, M. Tatewa-ki s.n. (holo- SAPS 21300 digital image!).

= O. parviflora Lej., Fl. Spa. 307. 1813. ≡ O. acetosella var. parviflora (Lej.) DC., Prodr. 1: 700. 1824. – Type: Belgium, circa Verviam & Malmundarum, A. Lejeune s.n. (lecto- BR 0000012172511 digital image!).

= O. taquetii R. Knuth in Notizbl. Bot. Gart. Berlin-Dahlem. 308. 1919. – Type: Korea, E. J. Taquet 613 (syn- E 00326129 digital image!).

= O. vulgaris Gray, Nat. Arr. Brit. Pl. 630. 1821. – Type: Not designated.

= O. vulgaris Gray var. caerulea Gray, Nat. Arr. Brit. Pl. 630. 1821. – Type: Not designated.

Herbs, perennial, winter green. Rhizomes elon-gate, covered with scale leaves and bases of peti-oles. Scale-like leaves triangular, sericeous when young. Base of petiole scaly, triangular, and seri-ceous when young, abscission layer round. Leaf-lets obcordate, ciliate; longest vein of terminal

Taxonomic Treatment

Key to taxa of Oxalis sect. Oxalis subsect. Oxalis in Eastern Asia and surrounding regions.

1a. Leaflets longer than their wide ................................................................................................................................................. 21b. Leaflets wider than their long .................................................................................................................................................. 32a. Lateral leaflets arranged at 90° angle from petioles ...................................................... 4b. O. griffithii subsp. wulingensis2b. Lateral leaflets arranged at 120° angle from petioles .......................................................... 4c. O. griffithii subsp. taimonii3a. Petals with dark purple spots at base; rhizome including scales less than ca. 2 mm thick ........................... 2. O. leucolepis3b. Petals without purple spots; rhizome including scales more than 3 mm thick ...................................................................... 44a. Apex of leaflet truncate; peduncle shorter than petiole at maturity of capsule ....................................... 3. O. obtriangulata4b. Apex of leaflet rounded or obtuse; peduncle longer than petiole at maturity of capsule ....................................................... 55a. Capsules oblong (more than twice as long as wide) ............................................................................................................... 65b. Capsules globular (less than twice as long as wide) ............................................................................................................... 76a. ITS sequence containing GTGGTTG, GCCTTTG, AAAAAAA, CACAATC, GGCCGAG, TTGTTGC, TTTGAAA, TGGTCTC, TCTTGAG, and CTTTGCC; plants of continental Asia (China, India, Bhutan, and Nepal) .............................

................................................................................................................................................ 4a. O. griffithii subsp. griffithii6b. ITS sequence containing GTGTTTG, GCCTTGG, AAATAAA, CACGATC, GGCGGAG, TCGTTGC, TTTAAAA, TGGTCTC, TCTCGAG, and CTTCGCC; plants of Japan ............................................ 5a. O. nipponica subsp. nipponica7a. Seeds more than 2.5 mm long, usually 3 or more mm long .................................................................................................... 87b. Seeds less than 2.7 mm long, usually 2.5 mm or less long ..................................................................................................... 98a. Capsules 4.1–8.3 mm long, ca. 6.7 mm on average; seeds 2.8–3.8 mm long, ca. 3.2 mm on average; diploid .......................

........................................................................................................... 5b-I. O. nipponica subsp. kantoensis var. kantoensis8b. Capsules 3.5–7.3 mm long, ca. 4.9 mm on average; seeds 2.0–3.3 mm long, ca. 2.8 mm on average; tetraploid ...................

............................................................................................................. 5b-II. O. nipponica subsp. kantoensis var. alpigena9a. Leaflets obcordate ............................................................................................................................................ 1. O. acetosella9b. Leaflets obtriangular, angles sometimes protruding ....................................................... 4d. O. griffithii subsp. formosana


leaflet ca. 5–25 mm long; both surfaces pubes-cent, abaxial surface whitish green, purple or red. Flowers solitary; peduncle and pedicel much lon-ger than petiole at maturity of capsule, pubescent, pedicel densely pubescent; bract apparently 1, acute to deeply emarginate, abaxial surface with 2 lines of dense hairs; sepals 5, ciliate, lanceolate, green or reddish, abaxial face pubescent; petals five, lanceolate, emarginate, white or rarely pink, sometimes blue when dried, always with yellow spots at base, veins sometimes pink or purple from base to margin; stamens 10, dimorphic: 5 longer and 5 shorter arranged alternately; anthers cream colored, with 2 locules arranged inward when immature, outward at maturity; filaments white, translucent; pistils 5; stigmas yellow, translucent, twisted, uneven; styles white, trans-lucent, smooth; ovary green; ovules 1 or 2 per locule. Capsule green, globular, sometimes spot-ted red, opening at maturity, ca. 4–6.7 mm long. Seeds covered with white translucent membrane when immature, turning brown and darken in age, asymmetrically ovoid, longitudinally ridged, ca. 1.7–2.7 mm long. Chasmogamous flowers from spring to early summer. Cleistogamous flowers from early summer to late autumn, few in midsummer.

Distribution. Japan, Sakhalin, Kuril Islands, Eurasia (temperate to subarctic region), Great Brit-ain, Ireland, Iceland (?) and northern Africa (?).

Habitat. Shady environments and on level ground, moss-covered rocks and fallen trees. Plants on rocks and fallen trees tend to be small-er, hence, variable in size.

Japanese name. Komiyama-katabami.

Notes. Lourteig (2000) cited several syn-onyms of O. acetosella and their types. We com-ment on some of them as follows: (1) we treat O. montana Raf. (= O. americana Bigelow) as a dis-tinct species because our previous study (Aoki et al. 2017) showed its unique phylogenetic position (see below). (2) Oxalis longiflora L. should be as-signed to other than subsect. Oxalis because its

lectotype [“Habitat in Virginia.” lecto- LINN 600.11, P00724040 digital image! designated by Reveal (2007)] could not be identified as O. ace-tosella or any of its allies based on its long, naked pedicel above the bracts and long petals. (3) Ox-alis acetosella var. violacea Westf. was also ac-cepted by Knuth (1930), but we have not verified the original literature. (4) We did not confirm the type specimens of O. acetosella var. caerulea and O. acetosella var. subpurpurascente.

Concerning the Japanese plants, the tetra-ploids of O. acetosella reported by Terao (1979) belong to another taxon as noted above. We syn-onymize O. acetosella var. longicapsula under O. nipponica subsp. nipponica based on the results of our phylogenetic analysis (Aoki et al. 2017).

Representative specimens examined. Japan. Nagano Pref., Shinshu: Shinshu Komagatake, 2 August 1880, col-lector unknown s.n. (TI). Tochigi: Nikko, 18 June 1878, collector unknown s.n. (TI). Nikko, 29 June 1878, G. K. s.n. (TI). Nikko Futaara yama, 12 June 1878, collector un-known s.n. (TI). South Korea. Gangwon: Mt. Hambeak, H. T. Im s.n., H. T. Im s.n. Switzerland. Kt. St. Gallen, E of St. Gallen-St. Fiden, 26 April 1980, E. Zogg 4518 (TAI).

2. Oxalis leucolepis Diels in Notes Roy. Bot. Gard. Edinburgh 5: 223–224. 1912.

≡ O. acetosella L. subsp. leucolepis (Diels) C. C. Huang & L. R. Xu in Fl. Reipubl. Popularis Sin. 43: 9. 1998. – Type: China, W. Yunnan, G. Forrest 4287 (holo- K 000692014 digital image!), G. Forrest 4287 (iso- E 00327127 digital image!; P 00724045 digital image!; IBSC 000803 digital image!).

Oxalis leucolepis is similar to O. acetosella in leaf shape, but is distinguished by the much thinner rhizomes with fewer scales. The scale leaves are covered with very short hairs, hence glabrous to the naked eye. The petals are clearly different: the base of the petals of O. leucolepis has purple spots and purple veins; O. acetosella has yel-low spots.

Rhizomes elongate; scale leaves sparse, triangu-lar, pilose when young. Leaflets obcordate, sparsely ciliate. Flower solitary; petals white, purple spot at base and purple veins from base to middle.


Distribution. China (south), India (north), Bhutan, and Nepal.

Representative specimens examined. China. Hubei: Shennongjia, 8 August 2015, S. Aoki 420 (TI).

3. Oxalis obtriangulata Maxim. in Mélanges Biol. Bull. Phys.-Math. Acad. Imp. Sci. Saint-Pé-tersbourg 6: 260. 1867. – Type: Russia, Primor-sky, Posyet Bay along wooded near post, K. Max-imowicz (lecto- LE designated by Tzvelev 1988 in Russian; syn- P 00724047 digital image!; syn- P 00724048 digital image!; syn- K 000692015 digi-tal image!; syn- L 0018241 digital image!; syn- GH 00241909 digital image!; syn- US 00101067 digital image!; syn- M 0172323 digital image!).

≡ O. japonica Franch. et Sav. var. obtriangu-lata (Maxim.) Makino, Ill. Fl. Jap. 400. 1940.

Herbs, perennial, deciduous. Rhizomes with dense scale leaves. Scale-like leaves triangular, pubescent when young. Leaflets ciliate, obtrian-gular, truncate but slightly emarginate; both sur-faces pubescent, abaxial surface whitish green, purple or red. Flower solitary; petals white, with purple veins from base to middle; peduncle pu-bescent, pedicel densely pubescent; sepals 2, lin-ear. Capsule green, oblong. Seeds asymmetrical, ovoid, longitudinally ridged, ca. 2.5 mm long. Chasmogamous flowers in spring. Cleistogamous flowers in early summer.

Distribution. China (Northeastern region), Korea, Japan, Russian Far East.

Japanese name. Ooyama-katabami.

Representative specimens examined. Japan. Nagano: Karuizawa, 27 April 2014, S. Aoki 34 (TI). Gunma: Mt. Narukami, 30 July 2014, S. Aoki 73 (TI). South Korea. Gangwon: Mt. Maekun, 29 June 2014, H. T. Im 106071 (TI).

4. Oxalis griffithii Edgew. & Hook.f., Fl. Brit. India 1: 436. 1872. – Type: Bhutan, Griffith 607 [lecto- K 000692016 digital image! designated by Hara (1955) as holo-].

Leaflets emarginate; Flower solitary; peduncle and pedicel pubescent; bract apparently 1, trun-cate to emarginate; sepals 5, lanceolate, green or reddish; petals 5, lanceolate, emarginate; stamens 10, dimorphic, longer 5 and shorter five arranged alternately; anthers with 2 locules; pistils 5; cap-sules opening at maturity.

Notes. Oxalis griffithii corresponds to Clade A (Fig. 1), which is well supported with 1.00 pos-terior probability in the Bayesian method, and 94 and 90 bootstrap values in the maximum likeli-hood (ML) method and maximum parsimony (MP) method. Except for the nominative subspe-cies, we recognize three subspecies within this clade based on their phylogenetic uniqueness and morphology.

4a. subsp. griffithii≡ O. leucolepis Diels var. griffithii (Edgew. &

Hook.f.) R.C. Srivast. in Novon 8: 203. 1998. ≡ O. acetosella L. subsp. griffithii (Edgew. & Hook.f.) H. Hara in J. Jap. Bot. 30: 22. 1955.

= O. hupehensis R. Knuth in Notizbl. Bot. Gart. Berlin-Dahlem 7: 308. 1919. – Type: China, Hubei, Patung [Badong], E. H. Wilson 264 (syn- P 00724042 digital image!; syn- US 00664174 digital image!; syn- E 00327135 digital image!).

Herbs, perennial. Rhizomes sometimes elongate, with scale leaves and bases of petioles. Scale-like leaves triangular to lanceolate, sericeous when young. Base of petiole scaly, triangular to oblong, and silky when young, abscission layer round, sometimes with 2 filmy or triangular appendages on margin. Leaflets ciliate, obtriangular; longest vein of terminal leaflet ca. 8–17 mm long; both surfaces pubescent. Peduncle and pedicel much longer than petiole at maturity of capsule; bracts truncate to emarginate, abaxial surface with 2 lines of dense hairs; sepals ciliate, green or red-dish, abaxially pubescent; petals usually white with yellow spots at base or sometimes with pink or purple veins from base to margin; anthers cream colored, arranged introrse before maturity, extrorse at maturity; filaments white, translucent;


stigmas yellow, translucent, twisted, uneven; styles white, purple or pink, translucent, equal in length; ovary green, ovule 1 or 2 per locule. Cap-sule oblong, ca. 5.5–12.7 mm long. Seeds covered with white translucent membrane when imma-ture, turning brown and darkening with age, asymmetrical, ovoid, longitudinally ridged, ca. 2.4–3.8 mm long. Chasmogamous flowers in spring. Cleistogamous flowers from early sum-mer to late autumn, few in midsummer.

Distribution. China, India, Bhutan, and Nepal.

Specimens examined. China. Sichuan: Mt. Emei, S. Aoki 79, March 2017 (TI).

4b. subsp. wulingensis (T. Deng, D. G. Zhang & Z. L. Nie) S. Aoki & J. Murata, comb. & stat. nov.

Basionym: O. wulingensis T. Deng, D. G. Zhang & Z. L. Nie in Syst. Bot. 38: 156. 2013. – Type: China, Hunan: Sangzhi, Badagongshan National Nature Reserve, 2 April 2007, Deng, Zhang & Nie 544 (holo- KUN; iso- PE 2452701 digital image!).

Rhizomes covered with base of petioles. Leaflets oblong, retuse, lateral leaflets arranged at 90° an-gle from petiole; petals pink with lilac veins. Capsule oblong.

Distribution. Endemic to China (Hubei and Hunan).

4c. subsp. taimonii (Yamam.) S. Aoki & J. Murata, comb. nov.

Basionym: O. taimonii Yamam. in J. Soc. Torp. Agric. 4: 51–52. 1932. (as “taimoni”) ≡ O. acetosella L. subsp. taemonii (Yamam.) S. F. Huang & T. C. Huang in Taiwania 35: 10. 1990. – Type: Taiwan, mont. Taihasenzan, , T. Ito s.n. (holo- TAI 118905!).

Rhizomes sparsely covered with base of petioles. Leaflets emarginate, obcordate, slightly longer than wide. Capsules globular.

Distribution. Endemic to alpine Taiwan.

Japanese name. Senzan-katabami.

Notes. Oxalis taimoni was named for the col-lector, Taimon Ito, and misspelled as “Oxalis tae-moni” by Huang and Huang (1990). Here, we cor-rect the Latin termination of the original spelling [International Code of Nomenclature Art. 60.8 (Turland et al. 2018)].

Representative specimens examined. Taiwan. Taic-hung: 369-shan-chung to Tsue-chih, Hsuehshan, J. C. Wang, S. F. Huang & W. S. Tang s.n. (TAI216849). Taic-hung: 369-shan-chung to Tsue-chih, Hsuehshan, J. C. Wang, S. F. Huang & W. S. Tang s.n. (TAI216844). Taic-hun: 369-shan-chung to Tsue-chih, Hsuehshan, J. C. Wang, S. F. Huang & W. S. Tang s.n. (TAI216846).

4d. subsp. formosana (Terao) S. Aoki & J. Murata, comb. nov.

Basionym: O. acetosella L. subsp. formosana Terao in Acta Phytotax. Geobot. 30: 61. 1979. ≡ O. acetosella L. subsp. griffithii var. formosana (Terao) S. F. Huang & T. C. Huang in Taiwania 35: 10. 1990. – Type: Taiwan, Alishan, 2 April 1977, K. Inoue & M. Sugiyama s.n. (holo- TI!).

Rhizomes sometimes elongate, covered with scale leaves and bases of petioles. Scale-like leaves sericeous when young. Base of petiole scaly, triangular to oblong, sericeous when young, abscission layer round. Leaflets ciliate, obtriangular, emarginate; longest vein of termi-nal leaflet ca. 6–12 mm long; both surfaces pu-bescent. Peduncle and pedicel much longer than petioles at maturity of capsule; bracts truncate to emarginate, abaxial surface with 2 lines of dense hairs; sepals ciliate, abaxially pubescent; petals white, rarely pink, with yellow spots at base; an-thers cream colored, introrse when immature, ex-trorse at maturity; filaments white, translucent; stigmas yellow, translucent, twisted, uneven; styles white, translucent, smooth; ovary green; ovule(s) 1 or 2 per locule. Capsule green, globu-lar, ca. 4.1–6.7 mm long. Seeds covered with white and translucent membrane when immature, asymmetrical, ovoid, longitudinally ridged, ca.


1.9–2.8 mm long.

Distribution. Taiwan and the Philippines (Lu-zon Island).

Japanese name. Arisan-katabami.

Representative specimens examined. Taiwan. Taitou: Heitou douro, T. Hosokawa 5352 (TAI064309). Kwaren: Nankotaizan, T. Suzuki, N. Hukuyama & H. Simada ST17586 (TAI064305). Kagi: Mt. Ali, S. Sasaki s.n. (TAI064302). Taihoku: Bunzangun, Babo Kuru, T. Suzuki & T. Nakamura ST183361 (TAI116801).

5. Oxalis nipponica S. Aoki & J. Murata, sp. nov.Oxalis nipponica cannot be distinguished from O. griffithii subsp. griffithii morphologically, but it has a ge-nome ca. 27 % larger than O. griffithii subsp. griffithii and a unique phylogenetic position according to Aoki et al. (2017).

Typus. Japan, Mie: Miyazumakyo, 17 April 2015, S. Aoki 145 (holo- TI!).

[O. acetosella L. var. japonica (Franch. & Sav.) Makino in Bot. Mag. (Tokyo) 22: 171. 1908, pro parte excl. typ.]

[O. acetosella L. subsp. japonica (Franch. & Sav.) H. Hara in J. Fac. Sci. Univ. Tokyo, Sect. 3, Bot. 6: 82. 1952, pro parte excl. typ.]

[O. acetosella L. subsp. japonica (Franch. & Sav.) H. Hara, Enum. Sperm. Jap. 3: 8. 1954, pro parte excl. typ.]

Herbs, perennial. Rhizomes covered with scale-like leaves and base of petioles. Scale-like leaves triangular to lanceolate, silky when young. Base of petiole oblong, silky when young, abscission layer round, sometimes with 2 filmy or triangular appendages on margin. Leaflets obtriangular, emarginate, ciliate; both surfaces pubescent, ab-axial surface whitish green, purple or red. Flower solitary; peduncle and pedicel much longer than petioles at maturity of capsule, pubescent, pedi-cel densely pubescent above bracts; petals 5, lan-ceolate, emarginate; stamens 10, dimorphic: lon-ger 5 and shorter 5 arranged alternately; anthers cream colored, with 2 locules, introrse before ma-turity, extrorse at maturity; pistils 5; stigmas yel-

low, translucent, twisted, uneven; styles white, rarely pink and translucent, equal in length; ova-ry green. Capsules green, sometimes spotted red, open at maturity. Seeds covered with white trans-lucent membrane when immature, brown and darkening in age, asymmetrical, ovoid, longitudi-nally ridged. Chasmogamous flowers spring to early summer. Cleistogamous flowers early sum-mer to late autumn, few in midsummer.

Distribution. Endemic to Japan.

Etymology. From the pronunciation of the name of the country, Nippon, in Japanese, where it is endemic. The specific epithet, japonica, is preoccupied by O. japonica Franch. & Sav.

Notes. Monophyly of Oxalis nipponica was well supported with 1.00 posterior probability in the Bayesian analysis, and 82 and 93 bootstrap values in ML and MP methods, but was divided into two clades (C & D in Fig. 1) (Aoki et al. 2017). The plants in the two clades can be distin-guished by the morphology of their capsules, but the confidence of Clade D is not strong (0.94 pos-terior probability, and 67 and 73 bootstrap values in ML and MP methods). Because of this uncer-tainty, we treat the plants of Clade D as a subspe-cies of O. nipponica rather than as a distinct spe-cies.

5a. subsp. nipponica —Fig. 2.[O. acetosella L. var. japonica (Franch. &

Sav.) Makino f. japonica Makino, Bot. Mag. (To-kyo) 22: 171. 1908, pro parte excl. typ.]

= O. acetosella L. var. japonica (Franch. & Sav.) Makino f. rubriflora Makino in Bot. Mag. (Tokyo) 22: 171. 1908. ≡ O. acetosella L. subsp. griffithii Edgew. & Hook.f. f. rubriflora (Makino) Terao in Acta Phytotax. Geobot. 30: 61. 1979. ≡ O. griffithii Edgew. & Hook.f. f. rubriflora (Makino) Sugim. ex Yonek. in J. Jap. Bot. 86: 234. – Type: unknown.

= O. acetosella L. var. longicapsula Terao in Acta Phytotax. Geobot. 30: 59. 1979. – Type: Ja-pan, Iwate: near Fuenuki-no-taki, 13 August


1976, H. Terao 328 (holo- KYO!).= O. acetosella var. longicapsula f. rosea

Terao in Acta Phytotax. Geobot. 30: 60. 1979. – Type: Japan, Fukushima: Yama-gun, Kitashioba-ra-mura, Y. Baba s.n. (holo- TNS 181261 digital image!).

Herbs, winter green. Rhizomes sometimes elon-gate. Longest vein of terminal leaflet ca. 7–30 mm long; bract apparently1, rarely 2. When 1, acute to bifid (liner when 2), abaxial surface with 2 lines of dense hairs. Sepals 5, ciliate, lanceo-late, green or reddish, abaxial face pubescent; petals white or sometimes pink, sometimes blue when dried, sometimes with yellow spots at base. Capsule oblong, ca. 6.4–16.5 mm long. Seeds ca. 2.5–3.9 mm long. Diploids and tetraploids.

Distribution. Endemic to Japan. Honshu (excl. Kanto region, Shizuoka Pref. and Yamanashi Pref.), Sado Island, Oki Island and Hokkaido (southern part).

Habitat. Oxalis nipponica subsp nipponica occurs from sea level to ca. 1,600 m. It prefers shady, wet environments, such as riverside for-ests and valley lines within forests. It is usually on the ground and rarely on rocks and fallen trees.

Japanese name. Miyama-katabami.

Notes. Oxalis nipponica can be recognized only by genome size and molecular analysis. It cannot be distinguished morphologically from O. griffithii subsp. griffithii, which does not occur in Japan.

No specimens were cited in the original de-scription of O. acetosella var. japonica f. rubri-flora, and no plausible original material was found in TI, MAK or MBK.

The Clade C (Fig. 1) included a sample from the type locality of O. acetosella var. longicap-sula. We were unable to distinguish that variety morphologically, hence we treat O. acetosella var. longicapsula as a synonym of O. nipponica subsp. nipponica.

Representative specimens examined. Japan. Suou: Kisiki, Kisiki village, 23 October 1892, J. Nikai s.n. (TI). Kishu: Mt. Koya, 18 July 1883, collector unknown s.n. (TI). Aomori: Zatouishi, collector unknown s.n. (MAK72707). Gifu: Sasagadake, M. Matsui s.n. (MAK72607). Kyoto: Tanba, S. Takami s.n. (MAK72615). Hokkaido: Hiyama, Kaminokunimura, Yunotai, M. Hara s.n. (KYO).

5b. subsp. kantoensis (Terao) S. Aoki & J. Murata, comb. & stat. nov.

Basionym: O. acetosella L. subsp. griffithii (Edgew. & Hook.f.) H. Hara var. kantoensis Terao in Acta Phytotax. Geobot. 30: 62. 1979. ≡ O. griffithii Edgew. & Hook.f. var. kantoensis (Terao) T. Shimizu in J. Phyotogeogr. Tax. 37: 120. 1989. – Type: Japan, Tokyo: Mt. Takao, 17 June 1977, H. Terao 354 (holo- KYO!).

Leaflets: adaxial surface sparsely pubescent or glabrous, abaxial surface pubescent, whitish green, purple or red. Bract apparently 1, truncate to bifid, abaxial surface with 2 lines of dense hairs; sepals lanceolate, green, ciliate, abaxial surface pubescent; petals white; anthers cream colored, locules 2; filaments white, translucent; styles white, translucent, equal in length. Cap-sules oblong.

Distribution. Japan (Kanto region, Shizuoka Pref., Shikoku District, and Kyusyu District to Yakushima).

Notes. Oxalis nipponica subsp. nipponica comprises Clade D (Fig. 1), has diploid and tetra-ploid individuals. The two ploidy levels differ in morphology, habitat and distribution. The dip-loids correspond to O. griffithii var. kantoensis (Terao) T. Shimizu while the tetraploids corre-spond to plants that Terao (1979) reported to be tetraploids of O. acetosella var. acetosella.

5b-I. var. kantoensis (Terao) S. Aok i & J. Murata, comb. nov.

Basionym: O. acetosella L. subsp. griffithii (Edgew. & Hook.f.) H. Hara var. kantoensis Terao


in Acta Phytotax. Geobot. 30: 62. 1979. ≡ O. griffithii Edgew. & Hook.f. var. kantoensis (Terao) T. Shimizu in J. Phytogeogr. Tax. 37: 120. 1989.

[O. acetosella L. var. japonica (Franch. & Sav.) Makino f. japonica Makino in Bot. Mag. (Tokyo) 22: 171. 1908, pro parte excl. typ.]

Herbs, winter dormant. Rhizomes sometimes elongate. Longest vein of terminal leaflet ca. 9–20 mm long; Petals sometimes with yellow spots at base. Capsules ca. 4.1–8.3 mm long. Seeds ca. 2.8–3.8 mm long.

Distribution. Japan (Kanto region and East Shizuoka pref.).

Habitat. Oxalis nipponica var. kantoensis oc-curs at relatively lower elevations (sea level to ca. 500 m) in shady, wet environments, such as river-sides, valley lines and on the north-facing slopes of mountains.

Japanese name. Kantou-miyama-katabami.

Representative specimens examined. Japan. Sagami: Oyama, 17 May 1900, collector unknown s.n. (TI). Mt. Tsukuba, T. Makino s.n. (MAK72596). Mt. Takao, T. Makino s.n. (MAK72598 three sheets). Mt. Takao, April 1904, T. Makino s.n. (MAK72599). Mt. Tsukuba, collec-tor unknown s.n. (MAK72595). Hakone, collector un-known s.n. (MAK72601). Mt. Tsukuba, O. Suzuki s.n. (MAK72717).

5b-II. var. alpigena S. Aoki & J. Murata, var. nov. ––Fig. 3.

Oxalis nipponica var. alpigena has been confused with O. acetosella. It can be distinguished from O. acetosella by its obtriangular leaves, and from O. nipponica var. kan-toensis by the smaller capsules and seeds. Typus. Japan, Kagoshima: Mt. Shibi, 20 June 2015, S. Aoki 239 (holo- TI!).

[Oxalis acetosella L. var. acetosella sensu Terao in Acta Phytotax. Geobot. 30: 58. 1979, pro parte excl. typ.]

Rhizomes often elongate. Longest vein of termi-nal leaflet ca. 9–17 mm long; Petals always with

yellow spot at base. Capsules ca. 3.5–7.3 mm long. Seeds ca. 2–3.3 mm long.

Distribution. Japan (western Shizuoka pref., Shikoku region and southern Kyusyu region, in-cluding Yakushima).

Habitat. Oxalis nipponica var. alpigena oc-curs at relatively higher elevations (ca. 1,000 m) than the diploid, var. kantoensis, and prefers shady environments.

Etymology. The epithet, alpigena, from the habitat at higher elevations than the diploids, but it does not grow in alpine regions.

Japanese name. Nankai-miyama-katabami.

Representative specimens examined. Japan. Tosa: Tsuetate toge, 26 July 1888, collector unknown s.n. (TI). Kumamoto: Kuma, Gokimura, April 1908, collector un-known s.n. (TI). Tosa: Agawa village, S. Watanabe s.n. (MAK72624). Kochi: Agawa village, T. Makino s.n. (MAK72626). Mt. Takao, T. Makino s.n. (MAK72597). Mt. Takao, T. Makino s.n. (MAK72590).

6. Oxalis trilliifolia Hook., Fl. Bor.-Amer. 118. 1831. as "trilliifolium"

≡ Hesperoxalis trilliifolia (Hook.) Small, N. Amer. Fl. 25: 27. 1907. – Type: USA. near Great Rapids of Columbia River, Douglas s.n. (holo- K 000693111 digital image!).

Rhizomes covered with bases of petioles. Leaf-lets obcordate. Flowers umbellate, 3–12 florets per inflorescence; petals white. Capsules oblong.

Distribution. Western North America.

Digitized specimens examined. USA. Washington: Clark Country, Whipple Creek County, 11 September 2015, Park Ben Legler 13860 (WTU). Washington: Pierce County, 15 May 2014, Etsuko Reistroffer 31 (WTU). Or-egon: Lincoln County, Coast Range, Gwynn Creek, 31 August 2007, Mark Fishbein 6042 (HPSU). All speci-mens were observed at the Consortium of Pacific North-west Herbaria Specimen Database (CPNWH).

7. Oxalis montana Raf. in Amer. Monthly Mag.


Fig.3. Oxalis nipponica subsp. kantoensis var. alpigena. A: Habit. B: Leaf. C: Rhizome. D: Flower, front view. E: Flower, side view. F: Fruit. (A–E: Japan, Miyazaki Pref., Mt. Wanitsuka, 10 April 2018. F: In cultivation, originally collected on Mt. Wanitsuka on 4 July 2018.).

Fig.2. Oxalis nipponica subsp. nipponica. A: Habit. B: Leaf. C: Rhizome. D: Flower, front view. E: Flower, side view. F: Fruit. (A–E: Japan, Tottori Pref., Mt. Nagi, 23 April 2018. F: Japan, Yamaguchi Pref., Souzu-kyo, 22 April 2018.).


& Crit. Rev. 2: 266. 1818.≡ O. acetosella L. subsp. montana (Raf.) Hul-

tén in Kongl. Svenska Vetensk. Acad. Handl., n.s. 7:146. 1958. – Type: Not designated.

= O. americana Bigelow ex DC., Prodr. 1: 700. 1824. – Type: Amer. bor. umbrosis, J. Big-elow (lecto- G-DC 217757/1 digital image! desig-nated by Lourteig 2000, International Code of Nomenclature Art. 9.9 (Turland et al. 2018)).

= O. americana Bigelow ex DC. f. rhodantha Fernald in Rhodora 20: 78. 1918. ≡ O. montana Raf. f. rhodantha (Fernald) Fernald in Rhodora 22: 144. 1920. ≡ O. acetosella L. var. rhodantha (Fernald) R. Knuth, Pflanzenr. 438. 1930. ≡ O. acetosella L. var. acetosella f. rhodantha (Fer-nald) Geerinck & Walravens in Taxonomania 20: 1–4. 2007. – Type: USA, New Hampshire, C. E. Faxon s.n. (holo- GH 00043712 digital image!).

Rhizomes elongate, covered with scale leaves and bases of petioles. Scale-like leaves triangular, sericeous when young. Base of petioles scaly, tri-angular, sericeous when young, abscission layer round. Leaflets obcordate, ciliate; both surfaces pubescent. Flowers solitary; petals white or pink. Capsules globular. Seeds brown, asymmetrically ovoid, longitudinally ridged.

Distribution. Eastern North America.

Specimens examined. Canada. Newfoundland: Burnt Islands, 1989, A. Bouchard et al. 89216 (GH). USA. Vir-ginia: Pembroke, 13 July 2015, S. Aoki 416 (TI).

8. Oxalis oregana Nutt. ex Torr. & A. Gray, Fl. N. Amer. 1: 211. 1838.

≡ Oxalis acetosella L. var. oregana (Torr. & A. Gray) Trel. in Mem. Boston Soc. Nat. Hist. 4: 90. 1888. ≡ Oxalis acetosella L. subsp. oregana (Torr. & A. Gray) D. Löve in Taxon 17: 89. 1968. – Type: USA. Oregon, woods, T. Nuttall s.n.; J. Scouler s.n.

= O. smalliana R. Knuth, nom. nov. in Notiz-bl. Bot. Gart. Berlin-Dahlem. 308. 1919, based on O. macra Small, N. Amer. Fl. 25(1): 26. 1907, not O. macra Schltr., Bot. Jahrb. Syst. 27: 155. 1900.

≡ O. oregana var. smalliana (R. Knuth) M.

Peck in Leafl. W. Bot. 7: 185–186. 1954. ≡ Oxalis oregana f. smalliana (R. Knuth) Munz in Aliso 4: 93. 1958. – Type: USA, California: Monterey Co., Santa Lucia Mountains, R. A. Plaskett 25 (holo- NY 00373733 digital image!).

Rhizomes covered with bases of petioles. Leaf-lets obcordate. Flowers solitary; petals white or pink, sometimes with pink veins. Capsules glob-ular.

Distribution. Western coastal North America.

Notes. Oxalis oregana var. tracyi Jeps., Man. Fl. Pl. Calif. 588. 1925. needs further research to determine its taxonomic status.

Possible syntypes of O. oregana are listed as follows: USA, Oregon, T. Nuttall s.n. (GH 00100450 digital image!); USA, Oregon, T. Nut-tall s.n. (NY 373734 digital image!).

Digitized specimens examined. USA. California: Humboldt County, Trinidad Sate Beach, 18 August 2010, C. Davidson 11787 (SRP). California: Humboldt County, Blair Grove, 18 May 1992, Michael R. Hays 491 (ID). California: Del Norte County, 6 May 1967, Gary Kuhl s.n. (SOC). All specimens were observed at CPNWH.

Oxalis acetosella L. × O. nipponica S. Aoki & J. Murata subsp. nipponica

≡ O. acetosella L. subsp. acetosella var. ace-tosella × O. acetosella L. subsp. griffithii (Edgew. & Hook.f.) H. Hara var. griffithii Terao in Acta Phytotax. Geobot. 30: 62. 1979. – Type: Japan, Nagano: Kamikochi, 21 May 1978, H. Terao 250 (holo- KYO!).

Morphologically similar to O. nipponica. Base of petals with yellow spots. Leaflets obtriangular with slightly round corner. Chasmogamous and cleistogamous flowers present. Capsules not seen. Genome size is approximately intermediate between the parental taxa.

Distribution. Japan, Nagano Pref., Kamiko-chi, on level ground preferred by O. nipponica rather than O. acetosella.

Ecology. Oxalis acetosella L. × O. nipponica


subsp. nipponica coexists with the parental taxa, but is rare. The parental taxa at this site flower at the same time. The hybrid appears to occur at low frequency in this populations. Oxalis nipponica at the same site lacks spots on the petals.

Notes. A sample of Oxalis acetosella L. × O. nipponica subsp. nipponica from this locality had the ITS type of O. nipponica subsp. nipponica and the chloroplast haplotype of O. acetosella (Aoki et al. 2017).

We would like to thank curators of herbaria KYO, MAK, MBK, SAPS, TAI, and TI for allowing us to observe specimens in their care.

References

Amano, M. 2001. Oxalidaceae. In: Iwatsuki, K., Boufford D.E. & H. Ohba (eds.), Flora of Japan, vol. IIb, pp. 283–286. Kodansha, Tokyo.

Aoki, S., T. Ohi-Toma, P. Li, C.-X. Fu & J. Murata. 2017. Phylogenetic, cytological and morphological com-parisons of Oxalis subsect. Oxalis (Oxalidaceae) in Eastern Asia. Phytotaxa 324: 266–278.

Aoki, S., T. Ohi-Toma & J. Murata. 2018. Addition to Aoki et al. (2017): phylogenetic position of Oxalis trilliifolia in subsection Oxalis (Oxalidaceae). Phyto-taxa 356: 238–240.

Deng, T., D. Zhang, Z. Liu, C. G. Tucker, H. Sun, J. Wen & Z. Nie. 2013. Oxalis wulingensis (Oxalidaceae), an Unusual New Species from Central China. Syst. Bot. 38: 154–161.

Geerinck, D. & E. Walravens. 2007. La forme à pétales pourpres d'Oxalis acetosella Linné: f. rhodantha (Fernald) Geerinck & Walravens comb nov. Taxono-mania 20: 1–4.

Hara, H. 1954. Enumeratio spermatophytarum japoni-carum, vol. 3. Iwanami Shoten, Tokyo.

Hara, H. 1955. Critical notes on some type specimens of East-Asiatic plants in foreign herbaria (1). J. Jap. Bot. 30: 19–26.

Huang, C. C., B. X. Huang & L. R. Xu. 1998. Oxalidace-ae. In: Xu, L. R. & C. C. Huang (eds.), Flora Reipubli-cae Popularis Sinicae, vol. 43 (1), pp. 3–17. Science Press, Beijing (in Chinese).

Huang, S.-F. & T.-C. Huang. 1990. Notes on the flora of Taiwan (8)– Oxalis acetosella and its allies. Taiwania 35: 7–11.

Huang, T.-C. & T.-S. Liu. 2003. Oxalidaceae. In: Hsieh,

C.-F., T.-C. Huang, Z.-Y. Li, H.-C. Lo, H. Ohashi, C.-F. Shen, J.-C. Wang & K.-C. Yang (eds.), Flora of Taiwan, 2nd ed., vol. 3. second edition, pp. 397–402. The editorial committee of the Flora of Taiwan, Tai-pei.

Knuth, R. G. P. 1914. Ein Beitrag zur Systematik und geographischen Verbreitung der Oxalidaceen. Bot. Jahrb. Syst. 50 (supple.): 215–237 (in Germany).

Knuth, R. G. P. 1930. Das Pflanzenreich 95. Verlag von Wilhelm Engelmann, Leipzig.

Linnaean herbarium – the Linnaean Collections. 2018. <http://linnean-online.org/linnaean_herbarium.

html> [accessed November 8, 2018].Liu, Q. R. & M. F. Watson. 2008. Oxalidaceae. In: Wu,

C.-Y., Raven, P. H. & D. Y. Hong (Eds.), Flora of Chi-na, vol. 11, pp. 2–6. Science Press, Beijing & Mis-souri Botanical Garden Press, St. Louis.

Lourteig, A. 2000. Oxalis L. subgéneros, Monoxalis (Small) Lourt., Oxalis y Trifidus Lourt. Bradea 7: 201–629.

Makino, T. 1908. Observatons [sic] on the Flora of Japan. Bot. Mag. (Tokyo) 22: 165–176.

Nasir, Y. 1979. Oxalidaceae. In: Nasir, E. & S. I. Ali (eds.), Flora of West Pakistan No. 4, pp.1–7. Gordon College, Rawalpindi.

Reiche, K. F. 1894.Zur Kenntnis der chilenischen Arten der Gattung Oxalis. Bot. Jahrb. Syst. 50: 259–305.

Reveal, J. L. 2007. Oxalis longiflora. In: Jarvis, C. E. (ed.), Order out of chaos. The Linnean Society of London, London.

Royal Botanic Garden Edinburgh – Herbarium catalogue. 2018. <http://data.rbge.org.uk/search/herbarium/> [accessed November 8, 2018].

Shimizu, T. 1989. New Names of Some Japanese Plants. J. Phytogeogr. Taxon. 37: 120.

Srivastava, R.C. 1998. Some new combinations from the flora of Sikkim. Novon 8: 203.

Terao, H. 1979. Phytogeographical and Taxonomical Studies on Japanese Oxalis acetosella s.l. Acta Phy-totax. Geobot. 30: 45–64.

Thiers, B. 2018. Index Herbariorum: A global directory of public herbaria and associated staff. New York Bo-tanical Garden's Virtual Herbarium. <http://sweet-gum.nybg.org/science/ih/> [accessed November 9, 2018].

Turland, N. J., J. H. Wiersema, F. R. Barrie, W. Greuter, D. L. Hawksworth, P. S. Herendeen, S. Knapp, W.-H. Kusber, D.-Z. Li, K. Marhold, T. W. May, J. Mc-Neill, A. M. Monro, J. Prado, M. J. Price & G. F. Smith. 2018, International Code of Nomenclature for algae, fungi, and plants (Shenzhen Code) adopted by the Nineteenth International Botanical Congress Shenzhen, China, July 2017. Regnum Vegetabile 159. Glashütten: Koeltz Botanical Books. <https://www.iapt-taxon.org/nomen/main.php> [accessed: Septem-ber 3, 2018].


Tzvelev, N. N. 1988. Oxalidaceae. In: Kharkevich, S. S. (ed.) ,Plantae vasculares orientis extremi sovietici 3. pp.136–139. Nauka, Leningrad (in Russian).

Yonekura, K. 2011. Taxonomic notes on vascular plants in Japan and its adjacent regions (II). J. Jap. Bot. 86: 230–241.

Received September 13, 2018; accepted April 1, 2019

taxonomic revision of oxalis subsect. (oxalidaceae)

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