Senecio micropifolius 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 : 152

2. Senecio micropifolius DC., Prodr. 6: 413. 1838.

Lectotypus (designated here): CHILE. Reg. Valparaíso: “Cordillères du Chili”, s.d. [III.1790], Haenke s.n. (G-DC [ G00487011 ]!; isolecto-: LP [LP002431 fragm.] image!, P [ P01816669 ] image!, PR-616634 image!) . Syntypus: CHILE. Reg. Valparaíso: sine loco [“ex Andium tractu Portillo dicto”], s.d. [II.1794], Née s.n. (G-DC [ G00487002 ]!, LP [LP002432 fragm.] image!, MA [ MA00232361 ]!) .

= Senecio looseri Cabrera in Lilloa 15: 152. 1949, syn. nov. Holotypus: ARGENTINA. Prov. Mendoza: entre Las Cuevas y El Cristo, II.1934, Ragonese 238 (LP [ LP000556 ] image!).

Notes. – As currently circumscribed, Senecio micropifolius is a suffrutescent plant reaching 40 cm tall with ascendant or erect branches and 2–5 discoid, erect capitula arranged in terminal, corymbiform synflorescences (CABRERA, 1949). The species is treated as endemic to the Andes of Atacama and Coquimbo. The study of the type material, and especially the most complete duplicate kept at P, reveals that it is a rather prostrate plant with branches not exceeding 10 cm long. The capitula are terminal and discoid, but solitary or up to two, and the indumentum is lanate but not much dense as in Johnston 6220 (type material of S. pelolepis I.M. Johnst. , synonymized with S. micropifolius by Cabrera in 1949).

The original material of Senecio micropifolius perfectly matches the taxonomic entity currently known under the name S. looseri Cabrera , a species described from Los Libertadores Pass with a distribution area restricted to the central Andes next to Santiago and Mendoza ( CABRERA , 1949). This agrees the fact that Haenke did not actually explored the high Andes of the Coquimbo Region (see below). According to MUÑOZ GARMENDIA (1994) the Expedition arrived at Coquimbo (from Valparaíso) on 18 April 1790 and rested there until 30 April, when the “Atrevida” (with Née) sailed northward to Arica and the “Descubierta” (with Haenke) headed to Desventuradas Islands. During the sojourn in Coquimbo, they botanized in its proximities, and Haenke, together with Pineda and Quintano, made a seven-day trip for visiting the gold mines of Andacollo (30°13'40"S 71°04'59"W) and the mercury mines of Punitaqui (30°51'42"S 71°14'07"W). Collections of S. micropifolius in Cabrera’s sense are not known from this region, which is not far from the coast and the mountains are barely higher than 1000 m. In contrast, as commented in the Introduction, Haenke passed through Los Libertadores Pass sometime in March 1790 to join the Expedition in Valparaíso after crossing the continent from Buenos Aires. Senecio looseri was described upon material collected from this region, and we believe that the original material of S. micropifolius most probably comes from this area too. It is interesting to note that the syntype of S. micropifolius at MA [MA00232361] (F ig. 5), which is in flower, very complete and well-preserved, bears a label with the locality “ex Andium tractu Portillo dicto”; El Portillo being located just before Los Libertadores Pass in the Chilean side. Née visited this locality at the end of F ebruary 1794, when left Santiago toward Buenos Aires. Then, over a four-year period and in opposite directions, Née and Haenke crossed Los Libertadores Pass around the same time, and all insights indicate that both collected the species treated here.

F or all these reasons, we believe that CABRERA (1949) misinterpreted the species concept of Senecio micropifolius , which was mostly based on a small fragment kept at LP that does not provide information about the plant habit. Cabrera stated that the fragment of the type material at LP corresponded to a plant with contracted synflorescence, identical to his own collection Cabrera 3559 from Baños del Toro in Coquimbo (c. 29°50'S 70°01'W, 3600 m). However, this latter collection does not match the morphology of the type because it contains plants densely branched with clearly erect, 10–25 cm long stems; it is here ascribed to S. pelolepis (see below). In contrast, the name S. micropifolius [1838] is referred to the species restricted to the Andes of Santiago and Mendoza, thus far named S. looseri [1949].

In the protologue of Senecio micropifolius two collections are cited, one from an undetermined place collected by Née and the other by Haenke from Chile. This perfectly fits with the two specimens kept at G-DC that are mounted on the same sheet: (1) G00487002 consists of a sterile plant bearing a label that reads “voy. de Née; h. Thibaud” [Née’s voyage; Thibaud herbarium]; (2) G00487011 consists of a flowering plant bearing a label that shows “Cordillères du Chili. Haenke”. Since Haenke’s collection is in flower, it is much more taxonomically informative. There is a specimen kept at PR identified in Candolle’s hand but the capitula are ruined. F or this reason, we designate here the specimen kept in G-DC [G00487011] as the lectotype of the name S. micropifolius because it is in best conditions and bears the species diagnostic characters.

Additional specimens examined. – ARGENTINA. Prov. Mendoza: Las Heras, Puente del Inca, quebrada de Los Horcones , camino a Plaza de Mulas , 3200–3500 m, 31.XII.1988, Cardiel et al. 149 ( MA) ; Las Cuevas, 3300 m, Pennington 8 ( G) . CHILE. Reg. Valparaíso: Estación Portillo F errocarril Transandino, 2800 m, 14–16.IV.1933, Looser 3152 ( LP) .