Lectotypification of the name Crocus sativus var
Transcription
Lectotypification of the name Crocus sativus var
Peruzzi & al. • Lectotypification of Crocus vernus TAXON 62 (5) • October 2013: 1037–1040 Lectotypification of the name Crocus sativus var. vernus L. (Iridaceae) and its consequences within Crocus ser. Verni Lorenzo Peruzzi, Angelino Carta & Fabio Garbari Department of Biology, Unit of Botany, University of Pisa, Via Luca Ghini 13, 56126 Pisa, Italy Author for correspondence: Lorenzo Peruzzi, lperuzzi@biologia.unipi.it Abstract The typification of the Linnaean name Crocus sativus var. vernus is discussed. A lectotype is designated from the Burser Herbarium at UPS. Due to changes in taxonomy and this lectotypification, it has not been possible to maintain the present strict usage of the name. Crocus vernus (L.) Hill should correctly be applied to the plants previously known as C. vernus subsp. albiflorus (Kit.) Ces. (≡ C. albiflorus Kit.). The next available name for the species to which the name C. vernus subsp. vernus has been misapplied is C. neapolitanus (Ker Gawl.) Loisel. Keywords Crocus; Crocus ser. Verni ; Linnaeus; nomenclature; taxonomy; typification Received: 12 Oct. 2012; revision received: 17 Apr. 2013; accepted: 18 June 2013. DOI: http://dx.doi.org/10.12705/625.7 INTRODUCTION Crocus L. (Iridaceae) belongs to the tribe Croceae, together with other bulbous genera such as Gladiolus L. and Romulea Maratti (Goldblatt & al., 2008). Crocus includes about 100 species (Kerndorff & Pasche, 2011; Peruzzi & Carta, 2011; Harpke & al., 2012; Ranđelović & al., 2012). According to Mathew (1982) it is subdivided into two subgenera: Crocus subg. Crocus and C. subg. Crociris B. Mathew. The former is further split into two sections and many series. Within Crocus sect. Crocus, there is C. ser. Verni B. Mathew, which includes many taxonomically critical taxa and is typified by Crocus vernus (L.) Hill., a name still lacking a formally designated type (Jarvis, 2007). The aim of this paper is to fix the application of the name Crocus sativus var. vernus L., fundamental for further systematic studies in Crocus ser. Verni. TYPIFICATION OF CROCUS SATIVUS VAR. VERNUS Linnaeus (1753), in the protologue, cited explicitly Bauhin (1623). Bauhin’s polynomials are linked with original material studied by Linnaeus in the Burser Herbarium in UPS (Stearn, 1957; Jarvis, 2007). In this herbarium are five specimens labelled as “Crocus vernus latifolius”: (1) “Ex Horto Leydensi ” (III: 63 post), with a well-preserved but incomplete (lacking bulb tunics) individual of unknown natural origin; (2) “In Gothardo Rhaetorum” (III: 64), with three well preserved and complete individuals from a well-defined geographic area; (3) “Basileae in horto Heinzmanni ” (III: 67), with three incomplete individuals of unknown natural origin; (4) “Annaebergae in horto meo. Sed bulbum acceperam a D. Lud. Jungermanno” (III: 68); and (5) “Ex Horto Leydensi ” (III: 68 post), each with a well-preserved and complete individual of unknown natural origin. All these specimens can be considered as part of the original material. Moreover, the Linnaean Herbarium (LINN!) contains one sheet (56.1; numbering follows Savage, 1945) which is marked “1. β sativus” manu Linnaeus, and can also be considered as original material for the name, because of the direct link to the variety β (image: http://www.linnean-online.org/768). The original material in the Burser Herbarium is very heterogeneous. Hence it is evident that Linnaeus’s circumscription of Crocus sativus var. vernus included several early-flowering crocuses, currently recognized as different species. Individuals in III: 67 are very incomplete and it is impossible to infer their precise identity following modern concepts; III: 68 and III: 68 post seemingly represent the same yellow-flowered unit (possibly belonging to Crocus ser. Flavi B. Mathew), which is very distant from the traditional application of C. vernus. Thus, all of these were excluded from the choice of lectotype. Sheet III: 63 post lacks bulb tunics and a definite geographical provenance is not given. Thus, this specimen cannot be positively identified; it may represent a plant falling within the traditional concept of Crocus vernus, but it might also represent a taxon not belonging to Crocus ser. Verni. Hence, an eventual selection as lectotype would result in future taxonomic uncertainties and subjective judgements. This problem cannot be solved by selecting a supporting epitype because within the current circumscription of C. vernus subsp. vernus (Mathew, 1980, 1982) at least three systematic units are included: (1) one, for which the name C. heuffelianus Herb. is available, widespread from Balkans to East Europe (2n = 12, 18, 19, 20, 21, 22, 23); (2) one, for which the name C. neapolitanus (Ker Gawl.) Loisel. is available (see discussion below), occurring in the central Mediterranean (2n = 8); and (3) one, so far included within C. vernus, presently lacking a formal taxonomic recognition and seemingly widespread in northwestern Italy (2n = 16). Which of these units should be selected to serve as epitype? It is evident that any choice would be arbitrary and there would be serious doubt as to whether the lectotype and Version of Record (identical to print version). 1037 Peruzzi & al. • Lectotypification of Crocus vernus epitype represented the same taxon. Specimen 56.1 in LINN (albeit likely conspecific with III: 64) is of unknown origin and presents the same problem as III: 63. Accordingly, we select the herbarium sheet III: 64 in the Burser Herbarium (UPS) as the lectotype of C. sativus var. vernus. Our choice does not strictly correspond with the current concept of the name Crocus vernus, so far applied to plants with flowers predominantly blue-violet and style mainly overtopping stamens (e.g., Mathew, 1982). On the contrary, there is a complete correspondence with the plants occurring in the mountains of southern Europe currently known as Crocus vernus subsp. albiflorus (Kit.) Ces. (≡ Crocus albiflorus Kit.) marked by flowers predominantly white and style deeply inserted within the stamens (Mathew, 1982). This was also largely confirmed by field surveys in the—from now on—locus classicus of C. ver nus (the San Gottardo area, in Ticino, Switzerland), in spring 2012 (Fig. 1). It is also interesting to note that Mathew (1982), despite applying the name to long-styled plants, cited as type locality “Switzerland”, evidently deriving this information from Hill (1765: “native of Switzerland”). Switzerland is apparently a portion of locus classicus citation in the Linnaean protologue (“Habitat in Alpibus Helveticis …”). Indeed, in recent floristic surveys of Switzerland only short-styled, predominantly white plants are known (Aeschimann & al., 2004; Lauber & Wagner, 2007, in both cases under the name C. albiflorus). TAXON 62 (5) • October 2013: 1037–1040 By studying topotypical Swiss material, it was also possible to establish the chromosome number, 2n = 8 (Fig. 2). As the morphological features, the diploid idiogram well agrees with the karyograms reported by Brighton (1976, under the name C. albiflorus), obtained from plants collected in Austria, N Italy and Slovenia: they are marked by homologous couples with apparent (especially the first and the latter) structural heterozygosities. Crocus vernus (L.) Hill, Veg. Syst., ed. 1, 10: 1765 ≡ Crocus sativus var. vernus L., Sp. Pl.: 36. 1753 – Lectotype (designated here): [Switzerland, Ticino] In Gothardo Rhae torum, Burser Herbarium III: 64 (UPS [digital image!]). — Figure 3. NOMENCLATURAL CONSEQUENCES As a result of our lectotypification of Crocus sativus var. vernus, Crocus albiflorus Kit (≡ Crocus vernus subsp. albiflo rus (Kit.) Ces.) becomes a heterotypic synonym of C. vernus (L.) Hill. Therefore, another name must be applied to the material that has been known as Crocus vernus or Crocus vernus subsp. vernus. We conclude that the oldest available name, at species level, for this taxon is C. neapolitanus (Ker Gawl.) Fig. 1. Flowers of Crocus vernus (L.) Hill from topotypical populations (Swiss Alps, Ticino, Airolo, San Gottardo area, 1100–1500 m a.s.l., 31 March–1 April 2012; herbarium specimens deposited in PI), expressing the whole range of chromatic variation of tepals. Flowering individuals bear white as predominant colour in more than 90% of cases. — Photographs by L. Peruzzi. 1038 Version of Record (identical to print version). Peruzzi & al. • Lectotypification of Crocus vernus TAXON 62 (5) • October 2013: 1037–1040 Loisel. Later isonyms are Crocus neapolitanus (Ker Gawl.) Ten. ex Hoppe in Flora 1: 588. 1818 and Crocus neapolitanus (Ker Gawl.) Ten., Semina: 11. 1825 (and not Cat. Hort. Neapol. 1813: 11. 1815, as it appears in www.ipni.org, since in that publication no Crocus name at all is present). We do not view the nomenclatural changes resulting from our lectotypification of Crocus sativus var. vernus to be disadvantageous and avoided by proposing to conserve the type of Crocus sativus var. vernus. Flora Europaea (Mathew, 1980) and Mathew’s (1982) Crocus monograph circumscribed Crocus vernus broadly, the short-styled white-flowered populations being treated as a subspecies (C. vernus subsp. albiflorus). Hence, what was C. vernus subsp. albiflorus is now C. vernus subsp. vernus and what was C. vernus subsp. vernus actually includes three systematic units, each to be recognised as species (D. Harpke & al., in prep.). Thus, nomenclatural stability was not possible under any scenario. Moreover, our choice has the advantage to definitely fix the application of the Linnaean name, without any identification ambiguities. Fig. 3. Lectotype of the name Crocus sativus var. vernus L. at UPS (In Gothardo Rhaetorum, Burser Herbarium III: 64). TYPIFICATION OF CROCUS NEAPOLITANUS Fig. 2. Crocus vernus (L.) Hill, microphotographs of four metaphasic plates (top) and diploid idiogram (bottom) obtained from plants collected in locus classicus (see caption of Fig. 1 for more information). Mean chromosome length ranges from 3.8 to 9.5 µm. The karyological protocol used is described in Peruzzi & Carta (2011). — Scale bars = 10 µm. Crocus neapolitanus (Ker Gawl.) Loisel. in Herb. Gén. Amateur 2: [101]. 1817 (“napolitanus”), non Hoppe 1818 ≡ Cro cus vernus var. neapolitanus Ker Gawl. in Bot. Mag. 22: t. 860. 1805 – Lectotype (designated here): illustration in Bot. Mag. 22: t. 860. 1805. — Figure 4. This species, described from Naples area in southern Italy (Sims, 1805), is diploid, marked by 2n = 8 chromosomes, and it is widespread in SE France, Italy, SW Austria and Slovenia (Brighton, 1976; Aeschimann & al., 2004, in both cases under the name C. vernus). Version of Record (identical to print version). 1039 Peruzzi & al. • Lectotypification of Crocus vernus TAXON 62 (5) • October 2013: 1037–1040 LITERATURE CITED Fig. 4. Lectotype of the name Crocus vernus var. neapolitanus Ker Gawl. (in Bot. Mag. 22: t. 860. 1805). ACKNOWLEDGEMENTS We are most grateful to Dr. Mats Hjertson, the Curator of UPS Herbarium, for help with original material for the name Crocus sativus var. vernus, to Ernst Bertschi for help in field survey logistics in Switzerland and to Charlie E. Jarvis (London) and Gerry Moore (Greensboro) for helpful and constructive comments on the manuscript. 1040 Aeschimann, D., Lauber, K., Moser, D.M. & Theurillat, J.-P. 2004. Flora alpina, vol. 2. Bologna: Zanichelli. Bauhin, C. 1623. Pinax theatri botanici. Frankfurt. http://dx.doi.org/10.5962/bhl.title.712 Brighton, C.A. 1976. Cytological problems in the genus Crocus (Irid aceae): I. Crocus vernus aggregate. Kew Bull. 31: 33–46. http://dx.doi.org/10.2307/4108994 Goldblatt, P., Rodriguez, A., Powell, M.P., Davies, T.J., Manning, J.C., Van der Bank, M. & Savolainen, V. 2008. Iridaceae “Out of Australasia”? Phylogeny, biogeography, and divergence time based on plastid DNA sequences. Syst. Bot. 33: 495–508. http://dx.doi.org/10.1600/036364408785679806 Harpke, D., Meng, S., Rutten, T., Kerndorff, H. & Blattner F.R. 2012. Phylogeny of Crocus (Iridaceae) based on the chloroplast and two nuclear loci: Ancient hybridization and chromosome number evolution. Molec. Phylogen. Evol. 66: 617–627. http://dx.doi.org/10.1016/j.ympev.2012.10.007 Hill, J. 1765. The vegetable system, 1st ed., vol. 10. London. Jarvis, C. 2007. Order out of chaos: Linnaean plant names and their types. London: Linnean Society of London and The Natural History Museum. Kerndorff, H. & Pasche, E. 2011. Two new taxa of Crocus (Liliiflorae, Iridaceae) from Turkey. Stapfia 95: 2–5. Lauber, K. & Wagner, G. 2007. Flora Helvetica. Bern: Haupt. Linnaeus, C. 1753. Species plantarum. Stockholm. http://dx.doi.org/10.5962/bhl.title.669 Mathew, B. 1980. Crocus L. Pp. 92–99 in: Tutin, T.G., Burges, N.A., Chater, A.O., Edmondson, J.R., Heywood, V.H., Moore, D.M., Valentine, D.H., Walters, S.M. & Webb, D.A. (eds.), Flora euro paea, vol. 5. Cambridge: Cambridge University Press. Mathew, B. 1982. The Crocus: A revision of the genus Crocus. Kew: Royal Botanic Gardens. Peruzzi, L. & Carta, A. 2011. Crocus ilvensis sp. nov. (sect. Crocus, Iridaceae), endemic to Elba Island (Tuscan Archipelago, Italy). Nordic J. Bot. 29: 6–13. http://dx.doi.org/10.1111/j.1756-1051.2010.01023.x Ranđelović, N., Ranđelović, V. & Hristovski N. 2012. Crocus jab lanicensis (Iridaceae), a new species from Macedonia, Balkan Peninsula. Ann. Bot. Fenn. 49: 99–102. http://dx.doi.org/10.5735/085.049.0116 Savage, S. 1945. A catalogue of the Linnaean Herbarium. London: Linnean Society of London. Sims, J. 1805. Curtis’s Botanical Magazine, vol. 22. London. Stearn, W.T. 1957. An introduction to the Species Plantarum and cognate botanical works of Carl Linnaeus. Pp. i–iv, 1–176 in: Linnaeus, C., Species plantarum, a facsimile of the first edition, 1753, vol. 1. London: Ray Society. Version of Record (identical to print version).