(2722) Bilimbia De Not. in Giorn. Bot. Ital. 2(1,1): 190. 1846, nom. cons. prop. Typus: B. hexamera De Not., typ. cons. prop. Bilimbia De Not. is a legitimate name; “Bilimbia (Rheede) Rchb.” (Handb. Nat. Pfl.-Syst.: 294. 1837), for long thought to be an earlier homonym, is not a validly published name (Veldkamp in Lichenologist 36: 191–195. 2004). De Notaris included two species, B. hexamera and B. tetramera; both names are validly published and legitimate. Fink (in Contr. U. S. Natl. Herb. 14: 85. 1910) designated B. hexamera as type, but Fink followed the American Code and so his typification may be superseded by any later typification not using a largely mechanical method of selection, unless in the interval his typification had been affirmed (Art. 10.5, 10.6 of the ICN; Turland & al. in Regnum Veg. 159. 2018). The name was not discussed by Clements & Shear (Gen. Fungi., ed. 2. 1931), but Santesson (in Symb. Bot. Upsal. 12: 436. 1952) designated B. tetramera as type, and his appears to be the next typification, consequently superseding that of Fink. In 1952, the typification of Bilimbia could be either affirmed or superseded, so Santesson was entitled to designate as type any of the species included by De Notaris. However, Hafellner (in Beih. Nova Hedwigia 79: 310. 1984) re-designated B. hexamera as type. His choice was repeated by Timdal (in Opera Bot. 110: 24. 1991) and has usually been followed since. Timdal noted that Santesson's choice “will not preserve current usage of the name”. Bilimbia hexamera is considered to be a taxonomic synonym of the species now usually known as Bilimbia sabuletorum (Schreb.) Arnold (in Verh. K. K. Zool.-Bot. Ges. Wien 19: 637. 1869), based on Lichen sabuletorum Schreb. (Spic. Fl. Lips.: 134. 1771). Bilimbia tetramera is now usually known as Mycobilimbia tetramera (De Not.) Vitik. & al. ex Hafellner & Türk (in Stapfia 76: 148. 2001), and one of its taxonomic synonyms is Mycobilimbia obscurata (Sommerf.) Rehm (in Rabenh. Krypt.-Fl., ed. 2, 1(3): 328. 1890), the type of Mycobilimbia (designated by Clements & Shear, l.c.: 315). If B. tetramera is the type of Bilimbia, then Bilimbia becomes a synonym of, and the correct name for Mycobilimbia. As usually circumscribed, the two genera are distinct; indeed, they are presently placed in different families (Mycobilimbia in Lecideaceae). Hafellner's and Timdal's preference for B. hexamera as type of Bilimbia is taxonomically sensible but inconsistent with the Code. The obvious solution is to conserve the name Bilimbia with B. hexamera as type. The type of B. hexamera itself is Schaerer, Lich. Helv. Exs. no. 209, the only collection that De Notaris cited. De Notaris also cited Lecidea sphaeroides η muscorum, the name accompanying the specimen in the exsiccata. That name was validly published by Schaerer, Lich. Helv. Spic.: 165. 1833, where Schaerer cited Lich. Helv. Exs. no. 209 and no other collection. However, that collection is not the type of L. sphaeroides η (= var.) muscorum as Schaerer cited several legitimate varietal names in synonymy. He also cited Lichen muscorum G.H. Weber, but with “?”, so his name is not a combination from Weber's name. The earliest name at the rank of variety that Schaerer included, directly or indirectly, within the scope of Lecidea sphaeroides var. muscorum was Lecidea fuscolutea var. sanguineoatra (Wulf.) Flörke (in Mag. Neuesten Entdeck. Gesammten Naturk. Ges. Naturf. Freunde Berlin 3: 305. 1809) (now Bryobilimbia sanguineoatra), making Schaerer's varietal name an obligate synonym of that name and nomenclaturally superfluous. There is thus no nomenclatural link between the type of Bilimbia hexamera and any earlier name. If this proposal is not accepted, Mycobilimbia will become a junior taxonomic synonym of Bilimbia, making it necessary to place its species under Bilimbia, and the species presently placed under Bilimbia will have to be placed under Myxobilimbia Hafellner (in Stapfia 76: 154. 2001), the type of which is Myxobilimbia lobulata (Sommerf.) Hafellner (l.c. 2001 ≡ Lecidea lobulata Sommerf. in Kongel. Norske Vidensk. Selsk. Skr. 19de Aarhundr. 2(2): 54. 1827 ≡ Bilimbia lobulata (Sommerf.) Hafellner & Coppins in Lichenologist 36: 195. 2004), a species that is close to but distinct from Bilimbia sabuletorum. The exact number of species affected is uncertain owing to taxonomic difficulties: at present I count 13 in Mycobilimbia (estimates by other authors vary from 4 to 26) and 13 in Bilimbia (3 or 4 according to other authors); some are common and widespread. Species presently placed in Mycobilimbia and Bilimbia (in the usual sense) have in the past mostly been placed in one of the “dustbin” genera, including Bacidia, Biatora and Lecidea. Attempts in recent decades to achieve a more natural classification of those large artificial groups have generated a fair amount of taxonomic and nomenclatural confusion and instability, and it seems to the author that where some degree of stability has finally been attained it would be very unhelpful to disturb it. Although the name Bilimbia was only taken up again by lichenologists in 2004, it is now widely accepted (in the sense that this proposal seeks to preserve) and the author considers that it is desirable to retain the name in that sense. LiA, https://orcid.org/0000-0002-8151-2838 Thanks to John McNeill for his usual constructive comments on the manuscript.