Senecio troncosii Philippi (1860: 32)

Calvo, Joel & Morales-Fierro, Vanezza, 2021, Nomenclatural adjustments in two South American species of Senecio (Compositae, Senecioneae), Phytotaxa 482 (2), pp. 219-222 : 219-220

1. Senecio troncosii Philippi (1860: 32) , “Troncosi”. Type:— CHILE. Atacama Region: Las Ánimas [26°26’S

70°27’W], [austral summer of 1853–1854], R. A. Philippi s.n. (holotype: SGO barcode 000006311!). Fig. 1A .

Senecio crepidoides Philippi (1894: 252) , nom. illeg., non S. crepidioides (Bentham in Hooker & Bentham 1849: 438) Ascherson in

Schultz Bipontinus (1867: 155), “crepidoides”. Type:— CHILE. Atacama Region: Piedra Colgada , [27°17’S 70°29’W], Sep 1885 ,

F. Philippi s.n. (Philippi’s material in SGO as the [first-step] lectotype, designated as “type” by Cabrera (1949: 454), SGO barcode

000006101! as the [second-step] lectotype, designated here; isolectotypes: SGO barcode 000006100!, LP barcode 002372 digital image!), syn. nov. Fig. 1B .

Distribution and habitat:— Endemic to northern Chile (Regions of Antofagasta, Atacama, Coquimbo). This species is distributed through the desert hills from southern Antofagasta to northern Coquimbo. Freire (2008) also reported this species from Valparaíso Region but she did not cite any collection supporting its presence there. We studied no specimen from this region either.

Notes: —Although Senecio crepidoides Philippi [1894] was accepted by Cabrera (1949), Marticorena & Quezada (1985), Freire (2008), and Rodríguez et al. (2018), it is an illegitimate later homonym of S. crepidioides (Bentham) Ascherson [1867] . After a detailed revision of the type material, we conclude that it cannot be distinguished from the earlier heterotypic and priority name S. troncosii Philippi [1860] . Cabrera (1949) underlined the morphological affinity between both taxa but separated S. crepidoides from S. troncosii by being a perennial plant (vs. annual, respectively) and having less divided leaves. The collections available at CONC and SGO reveal that this is an annual or biennial plant whose growth is likely closely related to the annual rainfall pattern; see e.g., Marticorena & al. 9817 (CONC 136300), Muñoz & al. 1083 (SGO 108670), Muñoz & Johnson 1903 (SGO 112139), Niemeyer s.n. (SGO 128282), Ricardi & al. 539 (CONC 70586), Vidal s.n. (CONC 58348). The leaf division is quite variable, and therefore, not useful for discriminating purposes; some plants display rather 1-pinnatisect leaves (e.g., Muñoz & al. 2725, SGO 123891) whereas the others have 2–3-pinnatisect leaves (e.g., Muñoz & al. 2697, SGO 123888). The remaining characters with taxonomic value in Senecio such as the involucre size, involucral bract number, and achene indumentum perfectly match each other. On the other side, no geographical pattern supports the recognition of more than a single species. On this basis, the illegitimate name S. crepidoides is treated as a synonym of S. troncosii ; see Cabrera (1949) for further details on the synonymy of the latter name.

Gynura crepidioides Bentham is the basionym of Ascherson’s name and it was originally spelled as “crepidioides”. Ascherson (1867) altered the epithet to “crepidoides” when transferred the species to the genus Senecio . On the other hand, Philippi’s name was originally spelled as “ S. crepidoides ” but Cabrera (1949) modified the epithet to “crepidioides” when published the taxonomic monograph of the genus Senecio from Chile. Since this epithet derives from a noun and a suffix, and therefore, it is not regulated as a genuine compound (see Turland et al. 2018, ICN Art. 60.10, Ex. 39), the respective original orthographies should be retained, i.e., “crepidioides” for Bentham’s name and “crepidoides” for Philippi’s name. Such minor dissimilarity does not preclude treating them as homonyms ( Turland et al. 2018, ICN Art. 53.2).

2. Senecio virens Philippi (1894: 259) . Iocenes acanthifolius subsp. virens (Philippi) Nordenstam (1978: 59) . Senecio acanthifolius subsp. virens (Philippi) Cabrera & Zardini (1980: 453) . Type:— CHILE. Los Lagos Region / Aysén Region: río Palena, Jan/ Feb 1887, F. Delfín s.n. (holotype: SGO barcode 000006321!). Fig. 2 . Senecio acanthifolius Hombron & Jacquinot (1845 : tab. 11-S), nom. illeg., non S. acanthifolius ( Reichenbach 1824: 17) Kosteletzky

(1833: 714). Iocenes acanthifolius Nordenstam (1978: 59) . Type:— CHILE. Magallanes Region: Port-Gallant / Port-Famine , 1841 ,

J.B. Hombron s.n. (lectotype, designated by Freire et al. (2014: 59): P barcode 02296261 digital image!; isolectotypes: P barcode

02296262 digital image!, P barcode 02296263 digital image!).

Distribution and habitat:— Argentina (Provinces of Chubut, Neuquén, Río Negro, Santa Cruz, Tierra del Fuego) and Chile (Regions of Aysén, Los Lagos, Los Ríos, Magallanes). This species is widely distributed through the Patagonian Andes of Argentina and Chile, growing in very humid forests.

Notes:— The name S. acanthifolius Hombron & Jacquinot [1845] has consistently been accepted in the literature dealing with Senecio in Argentina and Chile ( Cabrera 1949, Cabrera 1971, Cabrera & Zardini 1980, Marticorena & Quezada 1985, Freire 2008, Freire et al. 2014, Rodríguez et al. 2018). It is a later homonym of the validly published name S. acanthifolius (Reichenbach) Kosteletzky [1833] , hence, illegitimate. The priority name for this species is S. virens Philippi , which was described on the basis of material from the valley of the river Palena, in the limit of Los Lagos Region and Aysén Region.

According to the protologue, Philippi received a single specimen of S. virens consisting of a 30 cm long plant with a 12 cm long basal leaf. We located a specimen at SGO that should be that one studied by Philippi, and for that reason, it is considered the holotype of the name S. virens .

Figures

FIGURE 1. A. Holotype of Senecio troncosii (SGO barcode 000006311). B. Lectotype of S. crepidoides (SGO barcode 000006101).

FIGURE 2. Holotype of Senecio virens (SGO barcode 000006321).