(2929) Dipterocarpoxylon R. Holden in Rec. Geol. Surv. India 47: 271. Dec 1916, nom. cons. prop. Typus: D. schenkii (Felix) H.-J. Schweitz. (in Palaeontographica, Abt. B, Paläophytol. 105: 21. 1958) (Helictoxylon schenkii Felix), typ. cons. prop. (=) Hippocrateoxylon H.L. Hofm. in Z. Naturwiss. 57: 179. Mar–Apr 1884, nom. rej. prop. Typus: H. javanicum H.L. Hofm. The earlier years of palaeoxylology, a distinct branch of the anatomical study of fossil woods that was started in the 19th century, left unfortunate incorrect determinations leading to inappropriate fossil plant names. The genera of fossil woods, whose names were derived from the names of extant genera of plants, were sometimes later re-interpreted as belonging to different extant genera or families, and therefore such fossil names were in a dubious position, having a real conflict between the name and the lack of relationship with the putative extant genus, the stem of which was used in the composition of the fossil plant name. The fossil-generic name Dipterocarpoxylon R. Holden (in Rec. Geol. Surv. India 47: 271. Dec 1916) is the result of one such unfortunate determination. When Ruth Holden, a young botanist at the age of 26, published a generico-specific description for the fossil woods from now Myanmar (former Burma), she assigned these fossils to a new fossil-genus Dipterocarpoxylon, the name of which was formed from the stem of the suggested extant counterpart of the fossils, Dipterocarpus C.F. Gaertn. (Suppl. Carp.: 50. 1805), the extant genus thought to be most likely related to the Burmese fossils. However, in later studies, this putative relationship was questioned and eventually abandoned. So, Bancroft (in Förh. Geol. Fören. Stockholm 55: 83. 1933) advanced a hypothesis that Holden's fossil woods might be better related to Meliaceae Juss. (Gen. Pl.: 263. 1789 [‘Meliae’]), nom. cons., not Dipterocarpaceae Blume (Bijdr.: 222. 1825 [‘Dipterocarpeae’]). She pointed out (Bancroft in Amer. J. Bot. 22: 730. 1935) that “It is somewhat difficult to understand why this fossil, Dipterocarpoxylon burmense (Holden, 1916), from Tertiary strata of Burma, should have been so named, since not only are its rays unlike those of typical Dipterocarps, but also the general occurrence of secretory canals in the wood is doubtful.” Gupta (in Proc. Indian Acad. Sci., B, 1: 553. 1935) definitely rejected the assignment of these fossil woods to Dipterocarpus-type woods, and inadmissibly renamed them Irrawadioxylon K.M. Gupta (l.c.: 552), nom. illeg. At that time he was unable to find a closer extant counterpart of these fossil woods, and decided to place them in an etymologically neutral generic name. But Gupta denied relations with the family Dipterocarpaceae and suggested that his non-committal fossil-genus could be related “with the wood of an Ebenaceae and the Anacardiaceae” (Gupta, l.c.: 449). Later Chowdhury (in Curr. Sci. 21: 161. Jun 1952 and in Ann. Bot. (Oxford) 16: 376. 3 Jul 1952) was fortunate in obtaining fossil wood that allowed him to determine the extant genus to which the Burmese fossils could be related: he recombined them in his previously published generic name, Glutoxylon K.A. Chowdhury (in Curr. Sci. 3: 256. 1934), as G. burmense (R. Holden) K.A. Chowdhury (l.c. Jun 1952), recognizing that the closest relationship was with the wood type of the extant genus Gluta L. (Mant. Pl.: 293. 1771) of the different family Anacardiaceae R. Br. (in Tuckey, Narr. Exped. Zaire: 431. 1818 [‘Anacardeae’]), nom. cons. The close relationships in wood type between fossil Dipterocarpoxylon burmense R. Holden and extant Gluta travancorica Bedd. (Fl. Sylv. S. India 1: t. 60. 1870), the putative modern analogue of the fossil, a large tree, mainly distributed in the wet evergreen forests of the Western Ghats, south India, was recently confirmed in new palaeoxylological studies (Kar & al. in Palaeobotanist 53: 137. 2004; cf. also Prakash & Tripathi in Palaeobotanist 17: 59. 1969; Prakash & Awasthi in Palaeobotanist 18: 219. 1969; Prakash in Palaeobotanist 20: 48. 1973; Guleria in Palaeobotanist 32: 35. 1984; Mehrotra & al. in Palaeobotanist 55: 67. 2006; and Licht & al. in Rev. Palaeobot. Palynol. 216: 44. 2015; etc.). Needless to say this later renaming of these fossils was incorrect and inadmissible since Chowdhury (l.c. Jun 1952) included Dipterocarpoxylon burmense, the type of that earlier validly published generic name, in his later published name, Glutoxylon K.A. Chowdhury (l.c. 1934). The strict rules of priority of names in botanical nomenclature required him to take up Dipterocarpoxylon and to recombine the one species of Glutoxylon, G. assamicum (Chowdhury, l.c. 1934), under that generic name. But the conflict between the etymology of the name (derived from extant Dipterocarpus) and the exact established relationships with the anacardiaceous genus Gluta points out the desirability of retaining Glutoxylon for this type of wood fossils, following the established practice of the formation of fossil wood genera by means of adding to the stem of the extant genus the uniform termination -xylon for wood fossils. Consequently Glutoxylon is in current use, containing five accepted Tertiary fossil-species (The International Fossil Plant Names Index [IFPNI], http://ifpni.org; Prakash & Tripathi, l.c.: 63; Poole & Davies in Rev. Palaeobot. Palynol. 113: 261. 2001; Gregory & al. in I. A. W. A. J. Suppl. 6: 7–8. 2009; Shukla & al. in Palaeobotanist 65: 66. 2013). The fossil-generic name Dipterocarpoxylon should also not be eliminated from palaeobotanical systematics because, in spite of its anomalous type species, being a wood type related to Gluta (Anacardiaceae), the other 35 fossil-species currently included in Dipterocarpoxylon R. Holden (typo excl.) are representatives of the Dipterocarpus-type of wood (The International Fossil Plant Names Index [IFPNI], http://ifpni.org; Gregory & al., l.c.: 29; Prasad & Gautam in Palaeobotanist 65: 247. 2016; etc.). Such a curious situation necessitates the legitimization of the nomenclature in accord with the requirements of the modern Code. In revising the fossil wood remains of the Dipterocarpus-type, Schweitzer (in Palaeontographica, Abt. B, Paläophytol. 105: 1–66. 1958) amended the generic circumscription of Dipterocarpoxylon R. Holden by excluding its original type species, D. burmense R. Holden, and substituting it with a new type species [so-called “Lectotypus”], D. schenkii (Felix) H.-J. Schweitz. (Helictoxylon schenkii Felix, Foss. Hölzer W.-Ind.: 20. 12 Apr 1883), and thus produced a nomenclaturally inadmissible later homonym, Dipterocarpoxylon H.-J. Schweitz. (l.c.: 15) (non Holden 1916). The change of the type species could be accepted only if the generic name were conserved with this type; however, since 1958, no such proposal has ever been made. Unfortunately, Schweitzer (l.c.: 15–29) also inadmissibly included in his revised Dipterocarpoxylon the type of the name of the previously validly published fossil wood monotypic genus Hippocrateoxylon H.L. Hofm. (in Z. Naturwiss. 57: 179. 1884), H. javanicum H.L. Hofm. (l.c.), as D. javanicum (H.L. Hofm.) H.-J. Schweitz. (l.c.: 24). Hippocrateoxylon H.L. Hofm., when proposed, was thought to be a representative of the family Hippocrateaceae Juss. (in Ann. Mus. Hist. Nat. 18: 486. 1811 [‘Hippocraticeae’]) with some putative relationships to the extant genus Hippocratea L. (Sp. Pl.: 1191. 1753), but Schweitzer (l.c.: 24) showed the error in attribution of this fossil-species to that family. Although the provisions of the Code dictate the necessity to accept the earliest validly published fossil-generic name, i.e., Hippocrateoxylon H.L. Hofm., the conflict in the etymology of the fossil-generic name precluded this option for palaeoxylological systematists, none of whom would consider naming Dipterocarpus-like wood fossils as Hippocrateoxylon with an etymological track to Hippocratea! Although the Code (Art. 51.1) states that “A legitimate name must not be rejected merely because it, or its epithet, is inappropriate or disagreeable, or because another is preferable or better known (but see Art. 56.1 and F.7.1), or because it has lost its original meaning”, palaeoxylological practice rejects such a requirement altogether. As Glutoxylon K.A. Chowdhury (l.c. 1934) is a legitimate name, its continued use for a genus related to Gluta (Anacardiaceae) that includes the species, G. burmense (R. Holden) K.A. Chowdhury, the type of Dipterocarpoxylon R. Holden (1916), and the continued use of the latter generic name for some 35 species, but excluding its type, can be legitimized quite simply by conserving Dipterocarpoxylon with a different conserved type, that previously proposed as “Lectotypus” by Schweitzer (l.c.: 15), i.e., D. schenkii (Felix) H.-J. Schweitz. (l.c.: 21) (≡ Helictoxylon schenkii Felix, l.c.). Proposing also the rejection of Hippocrateoxylon H.L. Hofm. will ensure legitimate use of Dipterocarpoxylon, as well as Glutoxylon, as these names are currently applied. (2930) Dryobalanoxylon Den Berger in Verh. Geol.-Mijnb. Genootsch. Ned. Kolon., Ser. Geol. 7: 146. Aug 1923, nom. cons. prop. Typus: D. tobleri (Kräusel) Den Berger (Dipterocarpoxylon tobleri Kräusel). (=) Naucleoxylon Crié, Samml. Geol. Reichs-Mus. Leiden, Ser. 1, 5: 19. 1888, nom. rej. prop. Typus: N. spectabile Crié Schweitzer (in Palaeontographica, Abt. B, Paläophytol. 105: 1–66. 1958) was not the first to re-circumscribe Dipterocarpoxylon R. Holden by exclusion of its type and the simultaneous unfortunate inclusion of the types of previously validly published, but re-interpreted, fossil-generic names. This was first done by Kräusel (in Verh. Geol.-Mijnb. Genootsch. Ned. Kolon., Ser. Geol. 5: 267. 1922 & in Leidse Geol. Meded. 2(1): 1–6. 1926). Amongst other names, Kräusel inadmissibly included in Dipterocarpoxylon R. Holden emend. Kräusel the type of the monotypic Naucleoxylon Crié (in Samml. Geol. Reichs-Mus. Leiden, Ser. 1, 5(1): 19. 1888), N. spectabile Crié (l.c.) (≡ Dipterocarpoxylon spectabile (Crié) Kräusel, l.c. 1926: 2). Later Schweitzer (l.c.: 9) excluded this fossil-species from Dipterocarpoxylon recognizing it as belonging to Dryobalanoxylon Den Berger (in Verh. Geol.-Mijnb. Genootsch. Ned. Kolon., Ser. Geol. 7: 146. 1923) as Dryobalanoxylon spectabile (Crié) Den Berger (in Bull. Jard. Bot. Buitenzorg, sér. 3, 8: 498. 1927). As the fossil wood structure of Naucleoxylon Crié is similar to that of the extant dipterocarpaceous genus Dryobalanops C.F. Gaertn. (Suppl. Carp. 49. 1805), this assignment is now generally accepted (Gregory & al. in I. A. W. A. J. Suppl. 6: 29. 2009). However, Dryobalanoxylon is a name in current use, containing 17 currently accepted Tertiary fossil-species (The International Fossil Plant Names Index [IFPNI], http://ifpni.org) and so recombination of 17 recognized fossil-species into the hitherto monotypic Naucleoxylon on the basis of priority is considered senseless in terms of both the stability of palaeobotanical nomenclature and the resultant conflict in the etymology of Naucleoxylon when applied to fossil woods lacking any relationship or similarity to the wood of extant Nauclea L. (Sp. Pl., ed. 2: 243. 1762). Moreover no more fossils have been described under Naucleoxylon since the 19th century. Accordingly, conservation of Dryobalanoxylon Den Berger against Naucleoxylon Crié is proposed. (2931) Shoreoxylon Den Berger in Verh. Geol.-Mijnb. Genootsch. Ned. Kolon., Ser. Geol. 7: 144. Aug 1923, nom. cons. prop. Typus: S. palembangense (Kräusel) Den Berger (Caesalpinioxylon palembangense Kräusel). (=) Bredaea Göpp., Tertiärfl. Java: 55. Jun 1854, nom. rej. prop. Typus: B. moroides Göpp. (=) Grewioxylon J. Schust. in Kongl. Svenska Vetensk. Acad. Handl., N.F., 45(6): 14. 22 Apr 1910, nom. rej. prop. Typus: G. swedenborgii J. Schust. In addition to Naucleoxylon, Kräusel (in Verh. Geol.-Mijnb. Genootsch. Ned. Kolon., Ser. Geol. 5: 267. 1922) inadmissibly included in Dipterocarpoxylon the type of the monotypic Grewioxylon J. Schust. (in Kongl. Svenska Vetensk. Acad. Handl., N.F. 45(6): 14. 1910), G. swedenborgii J. Schust. (l.c.) (≡ Dipterocarpoxylon swedenborgii (J. Schust.) Kräusel (l.c. 1922), and the type of the monotypic Bredaea Göpp. (Tertiärfl. Java: 55. 1854), B. moroides Göpp. (l.c.: 56) (≡ Dipterocarpoxylon moroides (Göpp.) Kräusel (in Leidse Geol. Meded. 2(1): 4. 1926). [Bredaea Göpp. is listed in the Index Nominum Genericorum (ING) (https://naturalhistory2.si.edu/botany/ing/) with a note of a possible (para)homonymy with the generic name Bredia Blume (Mus. Bot. 1: 24. Nov 1849), but this possible homonymy has never been mentioned in palaeobotanical treatises, and there is no established custom to accept Bredaea Göpp. as a junior homonym. In addition, the somewhat analogous pair of parahomonyms, Silvia Vell. (Fl. Flum. 55. 7 Sep–28 Nov 1829 [“1825”]) and Silvaea Phil. (Fl. Atacam. 21. 1860) have been ruled as not sufficiently alike to be confused (ICN, Appendix VII – Wiersema & al., https://naturalhistory2.si.edu/botany/codes-proposals 2018+).] Den Berger (in Bull. Jard. Bot. Buitenzorg, sér. 3, 8: 495–498. 1927) reviewed the fossil wood species referred to Dipterocarpoxylon by Kräusel (l.c. 1922, 1926) and assigned many of them to genera with quite different relationships. Amongst these was D. moroides (Göpp.) Kräusel, based on Bredaea moroides, the original type of Bredaea Göpp., that Den Berger (l.c. 1927: 498) transferred to the fossil-genus Shoreoxylon Den Berger (in Verh. Geol.-Mijnb. Genootsch. Ned. Kolon., Ser. Geol. 7: 144. 1923), as S. moroides (Göpp.) Den Berger. [Den Berger (l.c. 1923: 144–145) had considered the wood of C. palembangense, the original type of the illegitimate monotypic Caesalpinioxylon Kräusel (l.c. 1922: 247), non Schenk (in Anales Soc. Esp. Hist. Nat. 18: 383, 391. 1889), to resemble that of the extant dipterocarpaceous genus Shorea Roxb. ex C.F. Gaertn. (Suppl. Carp. 47. 1805) rather than that of Caesalpinia and so renamed it Shoreoxylon palembangense (Kräusel) Den Berger; in so doing he validly published the replacement generic name, Shoreoxylon Den Berger.] As Shoreoxylon is in current use, containing 20 recognized fossil-species (The International Fossil Plant Names Index [IFPNI], http://ifpni.org), I see no reason to recombine 20 fossil-species in the still monotypic fossil-genus Bredaea Göpp. on the basis of priority; it is rational to keep Shoreoxylon following the established tradition of palaeoxylology to name the wood fossils from the stem of the related extant genus. Accordingly it is proposed for conservation against Bredaea, under which no further fossils have been described since the 19th century. The initial hypothesis of Kräusel (l.c. 1922) to transfer the monotypic fossil wood genus Grewioxylon J. Schust. to the later-published Dipterocarpoxylon was not supported in the wood anatomical re-studies by Schweitzer (l.c.: 9), who concluded that the type of Grewioxylon J. Schust., G. swedenborgii J. Schust., was not a wood related to extant Grewia L. (Sp. Pl.: 964. 1753), but was dipterocarpaceous and related to Shorea rather than Dipterocarpus. Schweitzer thus named it Shoreoxylon swedenborgii (J. Schust.) H.-J. Schweitz. (l.c.: 9, 47). Accordingly it is proposed that Shoreoxylon be also conserved against Grewioxylon. Since the fossil-generic name Grewioxylon is in current use, it is necessary to explain the proposal to reject the name rather than to conserve it with a different type. The heterogeneity of Grewioxylon and the lack of any proven Grewia-like fossil wood types among the 12 known fossil-species (The International Fossil Plant Names Index [IFPNI], http://ifpni.org) precludes the option of retaining it in palaeobotanical classification with a new type. Recognizing the affinity of Grewioxylon swedenborgii, Srivastava & Guleria (in Palaeobotanist 49: 531–532. 2000) proposed the replacement name “Grewinium” for the other seven then known species of Grewioxylon. Unfortunately, “Grewinium” was based on “Grewioxylon intertrappeum” Shallom (in J. Indian Bot. Soc. 42: 174. 1964 [“1963”]), which is not a validly published name as no type was indicated. Consequently “Grewinium” and the fossil-species names transferred from Grewioxylon with no critical revision of their real taxonomic assignment were also not validly published. Doweld (in Geophytology 51: 9. 2022) recently published Grewiaceoxylon for three species of the former Grewioxylon, but representing only fossil woods of the Upper Cretaceous (Maastrichtian) [Deccan Intertrappean] from Gondwanan Indostan. He noted that several other problematic fossil wood types published under Grewioxylon awaited re-classification in different fossil wood genera, not even related to an extant “Grewia-like” fossil wood type. ABD, https://orcid.org/0000-0003-0089-5919 I thank John McNeill for suggestions and valuable comments on the initial draft. It is a pleasure to thank Mrs Valentina Bublik (Fundamental Botanical Library of the National Institute of Carpology, Moscow) for bibliographic searches of the publication dates of botanical literature. The research is a contribution to the Palaeoflora Europaea Project, Palaeoflora of Russia (Palaeoflora Rossica) Project (NOM-22-006) and The International Fossil Plant Names Index (IFPNI, http://ifpni.org/).