(2945) Commelina nimmoniana J. Graham, Cat. Pl. Bombay: 224. Jun–Dec 1839 (Angiosp.: Commelin.), nom. utique rej. prop. Neotypus (vide Nandikar & Gurav in Phytodiversity 2: 81. 2015): India, Maharashtra, Mumbai, Malabar Hill Garden, 28 Sep 2013, Nandikar 1432 (SUK). The name Murdannia semiteres (Dalzell) Santapau (in Poona Agric. Coll. Mag. 41(4): 15. 1951) (Commelinaceae) has long been in near-exclusive use for a well-known species, distributed throughout tropical Asia and Africa. This species was originally described as Aneilema semiteres Dalzell (in Hooker's J. Bot. Kew Gard. Misc. 3: 138. 1851) based on specimens from Konkan, India. It is characterised by fleshy, subulate, semiterete leaves and Santapau (l.c.) transferred it to Murdannia Royle (Ill. Bot. Himal. Mts.: 403. Mar–Apr 1840). Two other species with similar vegetative features were described from India, namely, M. juncoides (Wight) Rao & Kammathy (in Bull. Bot. Surv. India 6: 3. 1965) (≡ Dichoespermum juncoides Wight, Icon. Pl. Ind. Orient.: t. 2078. 1853) and M. sahyadrica Ancy & Nampy (in Willdenowia 42: 79. 2012). Graham (Cat. Pl. Bombay: 224. 1839) described Commelina nimmoniana J. Graham (≡ Murdannia nimmoniana (J. Graham) Bole & M.R. Almeida in J. Bombay Nat. Hist. Soc. 83: 593. 1986 [‘1987’]) with the description “A small plant with discoloured linear pointed leaves.” Original materials of this name are not available, as the author did not cite a type nor could any specimen available to Graham be traced. Brenan (in Kew Bull. 7: 184. 1952) on the basis of the scanty description referred to Graham's name as a “nomen subnudum”. Consequently, POWO (https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:172881-1) did not recognize the name Commelina nimmoniana J. Graham (l.c.) as validly published and considered it to have been effectively published (inadvertently) at a later date, citing it as C. nimmoniana J. Graham ex C.B. Clarke in Candolle & Candolle (Monogr. Phan. 3: 191. 1881). The discoloured needle-like leaves, the features given by Graham (l.c.) are equally applicable to three species of Murdannia: M. juncoides, M. sahyadrica, and M. semiteres. Bole & Almeida (l.c.) synonymised M. semiteres (Dalzell) Santapau under M. nimmoniana. Nandikar & Gurav (in Phytodiversity 2: 81. 2015) designated a neotype for the latter name and treated M. juncoides and M. sahyadrica as varieties of it. Nampy & Joby (in Rheedea 18: 57. 2008) discussed the ambiguity concerning the identity of M. juncoides and treated it as distinct from M. semiteres based on its bulbous base, phenology (flower opens in the afternoon) and the seed-testa characteristics. Murdannia sahyadrica is distinguished by its orbicular petals, stamens arranged symmetrically around the central erect style, ovoid capsules and uniseriately arranged seeds. Dalzell's (l.c.) epithet, as Murdannia semiteres (Dalzell) Santapau, has been almost consistently used by subsequent workers in floristic works in parts of Africa, India and South-East Asia. However as neotypified by Nandikar & Gurav (l.c.), the earlier M. nimmoniana, based on Commelina nimmoniana, has priority over M. semiteres. Although Graham (l.c.) provided information on the form of the leaves and the colour of the flowers, this proves insufficient to ascertain Graham's intended identity for the name C. nimmoniana. Accepting M. nimmoniana would disrupt the widely accepted usage of M. semiteres, which appears in checklists and floristics works covering parts of Africa, India and South-East Asia (Malaisse in Troupin, Fl. Rwanda 4: 140. 1988; Karthikeyan & al., Fl. Ind. 2. Monocot.: 29. 1989; Nguyen, Checkl. Pl. Sp. Vietnam 3: 468. 2005; Faden in Fl. Trop. E. Africa, Commelin.: 55. 2012; Ancy & Nampy, Murdannia India: 104. 2015; Anonymous, Fl. Karnataka Checkl. 2: 235. 2019; Britto, Fl. Centr. N. Tamil Nadu 1: 261. 2019; Mao & Dash, Fl. Pl. India Annot. Checkl. Monocot.: 215. 2020; Narasimhan & Irwin, Fl. Pl. Tamil Nadu Compend.: 308. 2021) and online databases such as African Plant Database (https://africanplantdatabase.ch/en/nomen/11801), The Catalogue of Life (http://www.catalogueoflife.org/annual-checklist/2019/details/species/id/01d4fb2360d2d32ab6795076a4e28cc6), Flora of Zambia (https://www.zambiaflora.com/speciesdata/species.php?species_id=225830), GBIF (https://www.gbif.org/species/2764823), and POWO (https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:172881-1), all accessed 13 Dec 2022. In this context the only way to avoid this disadvantageous change of name and to ensure nomenclatural stability in the future is to reject Commelina nimmoniana J. Graham and the combination based on it. MKM, https://orcid.org/0000-0002-6975-480X SN, https://orcid.org/0000-0001-5744-7522 The authors thank Dr. John McNeill, Royal Botanic Garden Edinburgh, Scotland, U.K. and Dr. Subir Bandyopadhyay, Kolkata for helpful consultation in preparing this proposal. MKM and SN are thankful to RUSA and SERB for financial assistance.