(3136–3137) Proposals to conserve the names Impatiens alborosea Tardieu and I. cavaleriei X.X. Bai & R.X. Huang against I. alborosea Hook. f. ex H. Lév. and I. cavaleriei Hook. f. ex H. Lév. ( Balsaminaceae )

(3136) Impatiens alborosea Tardieu in Notul. Syst. (Paris) 11: 171. May 1944 [Angiosp.: Balsamin.], nom. cons. prop. Lectotypus (hic designatus): [Vietnam, Hoa Binh,] Lung Vân, 26 Jan 1931, Poilane 18885 (P barcode P00780664; isolectotypus: P barcode P00780665). (H) Impatiens alborosea Hook. f. ex H. Lév., Fl. Kouy-Tchéou: 176. 1914–1915 (‘albo-rosea’), nom. rej. prop. Lectotypus (hic designatus): [China, Guizhou,] Gan-pin [Pingba], 28 Oct 1897, Bodinier 1814 (P barcode P05249167; isolectotypus: P barcode P05249165). (3137) Impatiens cavaleriei X.X. Bai & R.X. Huang in Taiwania 68: 85. 21 Feb 2023 [Angiosp.: Balsamin.], nom. cons. prop. Typus: China, Guizhou, Qiannan Buyi and Miao Autonom. Pref., Duyun City, Doupeng Mountains, 26°21′01.85″N, 107°22′01.05″E, 1151 m, 8 Jul 2021, Bai & al. DPS-252 (GZAC [image!]; isotypus: PE). (H) Impatiens cavaleriei Hook. f. ex H. Lév., Fl. Kouy-Tchéou: 176. 1914–1915, nom. rej. prop. Lectotypus (hic designatus): [China, Guizhou, Qiannan Buyi & Miao Autonom. Pref., Luodian Co.,] Lo-Fou, Oct 1908, Cavalerie 3614 (K barcode K000694646; isolectotypus: K barcodes K000694647 & K000694648). In Augustin Abel Hector Léveillé's Flore du Kouy-Tchéou, he enumerated 19 species of Impatiens, providing a dichotomous key written in French and citing voucher specimens within the text (Léveillé, Fl. Kouy-Tchéou: 176–178. 1914–1915). Three new taxa—I. foetens Hook. f. ex H. Lév., I. cavaleriei Hook. f. ex H. Lév., and I. alborosea Hook. f. ex H. Lév.—were included in the key (l.c.: 176). As defined by Art. 38.1 and particularly Art. 38.2 (see Ex. 5) of the International Code of Nomenclature for algae, fungi, and plants (Madrid Code) (Turland & al. in Regnum Veg. 162. 2025), the distinguishing portion of the key couplets would constitute diagnoses. Although the diagnostic traits in the parallel key for these three names are rather brief, and Lauener (in Notes Roy. Bot. Gard. Edinburgh 27: 267. 1967) considered that “they were never described and must therefore be regarded as nomina nuda”, it is unquestionable that these three names were validly published (Art. 38). It is noteworthy that Léveillé provided the annotation “(Sir Hooker det.)” in his research of the genus Impatiens L., denoting that the specimens involved were all identified by J.D. Hooker, to whom the names were ascribed, but it was Léveillé who wrote the key and to whom authorship of the new names must therefore be attributed (Art. 46.5). The key entries involving Impatiens cavaleriei Hook. f. ex H. Lév. and I. alborosea Hook. f. ex H. Lév. (l.c.: 176) could be paraphrased (in English) as follows: I. cavaleriei Hook. f. ex H. Lév. was distinguished from I. piufanensis Hook. f. (‘pinfaensis’) (in Hooker's Icon. Pl. 29: t. 2869. 1909) and several other species of Impatiens occurring in Guizhou Province by the leaf margins being crenate, not serrate; the peduncle invariably uniflorous; with flowers white or yellow; and all pedicels bearing a bract at the base. Impatiens alborosea Hook. f. ex H. Lév. was distinguished from I. apalophylla Hook. f. (in Nouv. Arch. Mus. Hist. Nat., sér. 4, 10: 243. 1908) and other species by the flowers yellow dotted with purple inside, crimson pink outside; by having 4 sepals; with flowers in racemes; and all pedicels being bracteate. Based on an examination of the cited voucher specimens, Impatiens alborosea Hook. f. ex H. Lév. (l.c.) possesses clavate capsules and belongs to I. subg. Clavicarpa S.X. Yu. It was collected from Gan-pin (now Pingba District, Anshun city), Kouy yang (Guiyang city), and Pin Fa (now Yunwu town, Guiding County) in Guizhou. Field studies indicate that I. guizhouensis Y.L. Chen (in Acta Phytotax. Sin. 37: 97. 1999) is morphologically highly similar and geographically overlapping and should be treated as a heterotypic synonym. However, Tardieu (in Notul. Syst. (Paris) 11: 171. 1944) applied the same epithet ‘alborosea’ to I. alborosea Tardieu, a species within I. sect. Semeiocardium (Zoll.) S.X. Yu & Wei Wang, from Central Vietnam (Annam). He provided a detailed description with voucher specimens and characterized it by connate lateral united petals, a bifid spur, and 2 sepals. Likewise, Impatiens cavaleriei Hook. f. ex H. Lév. (of I. sect. Uniflorae Hook. f. & Thomson) was collected from Lo Fou (now Luodian County, Qiannan Autonomous Prefecture) and is identified by 1–2-flowered peduncles and fusiform capsules, and is morphologically indistinguishable from Guizhou's widespread I. pulchra Hook. f. & Thomson (in J. Proc. Linn. Soc., Bot. 4: 139. 1859) (Singh & al. in Biodivers. Res. Conservation 61: 1–27. 2021). In a parallel case, the epithet ‘cavaleriei’ was also used for I. cavaleriei X.X. Bai & R.X. Huang (in Taiwania 68: 85. 2023) in I. sect. Impatiens, which is distinguished by leaf blades ovate-elliptic, apex obtuse; lower leaves with petiole 5–8 cm long, uppermost leaves subsessile, and by axillary inflorescences twisted beneath the leaves, having a single developed flower (with two flower buds). Even though the text written by Léveillé in his dichotomous key satisfies the definition of a diagnosis, such a treatment remains an unsound taxonomic practice. As demonstrated by the research history of Balsaminaceae, the three names mentioned here have scarcely been adopted and are not listed in the International Plant Names Index (IPNI; https://www.ipni.org/). Their forcible adoption would result in disadvantageous nomenclatural changes. It is therefore proposed to conserve the currently accepted but illegitimate later homonyms Impatiens alborosea Tardieu and I. cavaleriei X.X. Bai & R.X. Huang against the long-ignored earlier homonyms I. alborosea Hook. f. ex H. Lév. and I. cavaleriei Hook. f. ex H. Lév. (l.c.), which have not been used for over 110 years. Revival of the latter would require the publication of replacement names for the former two, and would necessitate treating the widely accepted I. guizhouensis as a synonym. This would seriously disrupt the current usage of two accepted names, adversely affecting nomenclatural stability in Impatiens. We are grateful to Mr. Zhenhao Feng from Bazi Collection & Botanical Garden for his valuable suggestions on the revision of the draft, and appreciate Mr. John McNeill and Mr. John Wiersema for substantive comments, which have greatly improved the quality of our draft. Moreover, this study was supported by the Key Project of Guizhou Basic Research Program in 2026: Molecular Phylogenetic Study of Wild Impatiens in the Karst Plateau of Guizhou Based on Rad-seq.