(2919) Proposal to reject the name Dendrobium brownii ( Orchidaceae )

(2919) Dendrobium brownii F. Dietr., Nachtr. Vollst. Lex. Gartn. 10: 122. Jun–Oct 1824 (Angiosp.: Orchid.), nom. utique rej. prop. Lectotypus (vide Cribb in Kew Bull. 41: 665. 1986): Australia, Brown [5510] (BM barcode BM000505781; isolectotypus: K barcode K001085316). One of the best-known orchids of Australia and New Guinea is currently called Dendrobium discolor Lindl. (in Edwards's Bot. Reg. 27: ad t. 52, Misc.: 21, no. 50. 1841). During the 19th and much of the 20th century the most widely accepted name for this species was, however, D. undulatum R. Br. (Prodr.: 332. 1810). It was either overlooked or ignored that the earlier D. undulatum (Ruiz & Pav.) Pers. (Syn. Pl. 2: 524. 1807), now known as Xylobium undulatum (Ruiz & Pav.) Rolfe (in Orchid Rev. 20: 43. 1912), made Brown's name illegitimate. When he first described Dendrobium discolor, Lindley did not refer to D. undulatum, but only a year later (in Edwards's Bot. Reg. 28, Misc.: 3, no. 6. 1842) he wrote: “Upon re-examining the species of this genus I have found that the plant published lately under the above name [D. discolor], although from Java, is the same as D. undulatum found by Dr. Brown on the north coast of New Holland, and before him by Sir Joseph Banks in the same country. The reader will therefore be good enough to expunge the name of D. discolor, and to substitute that of D. undulatum.” Lindley mistakenly assumed that his D. discolor came from Java. It was in fact only cultivated there, in the Buitenzorg (now Bogor) Botanical Garden, from where it was sent to the Loddiges nursery in England; the actual origin was almost certainly New Guinea. In the second half of the 20th century, the name Dendrobium undulatum finally fell out of favour and the oldest heterotypic synonym, D. discolor, became generally used. The extensive synonymy of D. undulatum was recently summarised by Ormerod (in Orchadian 20: 361–365. 2022). Ormerod, and before him Mabberley (in J. Bot. Res. Inst. Texas 14: 242. 2020), pointed out that not everyone in the 19th century had failed to notice that D. undulatum R. Br. was preceded by D. undulatum (Ruiz & Pav.) Pers. In 1824, Friedrich Dietrich had proposed the replacement name D. brownii F. Dietr. (Nachtr. Vollst. Lex. Gartn. 10: 122. 1824) for D. undulatum R. Br. Mabberley (l.c.: 241–253) has argued that at least part of the work of Dietrich was not merely overlooked but deliberately ignored, and it may be that the name D. brownii fell victim to this attitude. We have, in any case, been unable to find any 19th or 20th century citation of the name outside Dietrich's work and it was not listed in the Index Kewensis. Ormerod (l.c.) correctly pointed out that Dendrobium brownii is a valid and older name for the species currently known as D. discolor. However, in our opinion there are several reasons why adopting the name D. brownii would be a disadvantageous nomenclatural change and that these reasons imply that it would be best to formally reject the name in the sense of the Code (Art. 56). 1. The name Dendrobium brownii has never been in use since it was first proposed in 1824. 2. This is a well-known species both in the wild and in cultivation, for which the name Dendrobium discolor is now firmly established. Cribb (in Kew Bull. 41: 665. 1986) called it “probably the most widely cultivated and best known species in the section [= sect. Spatulata]”. 3. There is an extensive body of literature in the fields of taxonomy, floristics, horticulture, and conservation in which the name Dendrobium discolor has been used. 4. Dendrobium discolor is an important species in horticulture, especially as a parent in hybridization. There are more than 250 primary crosses where it has been used as a pollen or pod parent, and the further breeding from these crosses has resulted in many thousands of hybrids, cultivated or sold as cut flowers all over the world. Changing the name of such an iconic species, first collected for Western science during Cook's voyage to Australia in 1770, would undoubtedly meet with strong disapproval among conservationists and horticulturalists. Although it is true to say that Dietrich's work was unfairly neglected, we believe that it is now too late to make amends, and that the name Dendrobium brownii F. Dietr. is best added to the list of nomina utique rejicienda. PA, https://orcid.org/0000-0001-9364-8444 AS, https://orcid.org/0000-0001-6701-8158