Senecio adscendens DC., Prodr.

Calvo, Joel & Granda, Arturo, 2022, On the taxonomic identity of five Senecio species (Compositae) described by Candolle on material collected by Haenke during the Malaspina Expedition, Candollea 77 (2), pp. 145-158 : 150-152

1. Senecio adscendens DC., Prodr. 6: 423. 1838 [nom. illeg., non Bojer ex DC., 1838].

Senecio andinus H. Buek, Gen. Sp. Synon. Cand. 2: VI. 1840 [nom. nov.]. Senecio floccoso-araneosus Steud., Nomencl. Bot. (Ed. 2) 2: 560. 1841 [nom. illeg. superfl.], syn. nov. Lectotypus (designated here): ARGENTINA / URUGUAY: “Peruano montano” [mislabeling], s.d., Haenke s.n. (PR-612170 image!; isolecto-: PRC [PRC453196] image!) (F ig. 4).

= Senecio cuspidatus DC., Prodr. 6: 419. 1838. Lectotypus (designated by F REIRE et al., 2014: 153): BRAZIL. Rio Grande do Sul: province de Rio-Grande, 1833, Gaudichaud 920 (P [P01816675] image!; isolecto-: G-DC [G00487165]!, P [P01816674] image!).

= Senecio montevidensis (Spreng.) Baker , F l. Bras. 6(3): 307. 1884. Cineraria montevidensis Spreng., Syst. Veg. [Sprengel, editio 16] 3: 548. 1826. Lectotypus (designated by F REIRE et al., 2014: 153): URUGUAY. Dept. Montevideo: Montevideo, s.d., Sellou s.n. (P [P01816677] image!).

Notes. – Senecio adscendens DC. [1838: 423] , presumably from Peru, was published simultaneously with S. adscendens Bojer ex DC. [1838: 378] , a species from Madagascar. Two years later, BUEK (1840) provided the replacement name S. andinus H. Buek for the Andean species, hence, treated S. adscendens Bojer ex DC. as having priority over S. adscendens DC. (TURLAND et al., 2018: ICN Art. 53.5).

Senecio andinus was recorded for the Peruvian flora by DILLON & HENSOLD (1993) and VISION & DILLON (1996), but without further information concerning its distribution. The protologue of S. adscendens certainly indicates Peru as the provenance of this species, but its morphology does not match any of the known species from this region. The study of the original material allows us to identify S. adscendens as conspecific with S. montevidensis (Spreng.) Baker , a species distributed in C and NE Argentina, SE Brazil, and Uruguay that usually thrives in dunes and sandy soils (F REIRE et al., 2014). Such mismatch can be explained by a mislabeling of the original material as in other cases documented here and in numerous works (see Introduction).

Due to an epistle sent by Haenke to the company Hiecke & al. in Cádiz, dated 7 December 1789 in Montevideo, we know that he shipped a box with dried plants to be kept in Cádiz until his return (KOHL, 1911). These plants were most probably collected in Montevideo, however, it is quite striking that he was able to collect and process the specimens within a period of two weeks after the shipwreck. No trace on specimen labels supports the existence of collections coming from Río de la Plata, but Haenke remained almost three months between Montevideo and Buenos Aires and it is expected that he would have collected plants. On the other side, it is also feasible to think that plants from this region were collected in the beginning of his journey to Valparaíso when he left Buenos Aires; actually, it is known that he collected a great amount of plants during this period (MALASPINA & BUSTAMANTE, 1885). Leaving aside this issue, Senecio montevidensis is frequent in central and northeastern Argentina (ARECHAVALETA, 1906; CABRERA , 1963; F REIRE et al., 2014), and therefore, one can assume that the original material of S. adscendens comes from this area.

Senecio montevidensis is characterized by having leaves linear to linear-oblanceolate, entire or with some teeth on the upper half, gray tomentose; capitula radiate; involucres composed of 16–20 involucral bracts; and achenes shortly but densely pilose. It is similar to S. ceratophylloides Griseb. , from which it can be differentiated by the smaller involucres (9–10 mm vs. 12–15 mm long) and the leaves narrower and less dentate ( CABRERA , 1963; CABRERA & F REIRE, 1999). With regard to the lectotypification made by F REIRE et al. (2014), we exclude P01816676 from type material because the locality differs from the lectotype.