Stellaria villasenorii Montesinos & Borsch, 2023

Montesinos-Tubée, Daniel B. & Borsch, Thomas, 2023, Molecular phylogenetics and morphology reveal the Plettkea lineage including several members of Arenaria and Pycnophyllopsis to be a clade of 21 South American species nested within Stellaria (Caryophyllaceae, Alsineae), Willdenowia 53 (3), pp. 115-148 : 139

19. Stellaria villasenorii Montesinos & Borsch , nom. nov.

≡ Pycnophyllum lanatum Phil. in Anales Univ. Chile, I, Mem. Ci. Lit. 81(6a): 774. 1892 [non Stellaria lanata Hook. f., Fl. Brit. India 1: 232. 1874] ≡ Baretia lanata (Phil.) Timaná in Adansonia, ser. 3, 45: 502. 2023 .

– Lectotype (designated by Timaná 2023: 502): Chile, Las Mollacas, Cordillera de Illapel , Jan 1888, R. Philippi s.n. ( SGO000001980 [image!]) .

Morphological description — See Timaná (2005).

Distribution — Mountain plateaus in Coquimbo, Chile, at altitudes of 2600–2800 m, endemic.

Etymology — The species name is chosen to honour Rodrigo A. Villaseñor Castro (1947–, Concepción, Chile), a professor in Biology and Natural Sciences, who extensively contributed to the knowledge of the Chilean flora.

Notes — The species conspicuously deviates from the other members of the Plettkea clade by its dense lanuginose indumentum and by its shrubby habit.

Timaná (2005) proposed to classify this species in its own new subgenus, Pycnophyllopsis subg. “ Coquimbo ”, but this name, because it appeared in a thesis, was not effectively (and therefore not validly) published according to Art. 30.9 of the Code ( Turland & al. 2018). The same applies to the species combination under Pycnophyllopsis and the lectotypification, all of which were not included in Timaná’s (2017) paper on the genus. Flower and seed morphology provide evidence for a position in the Plettkea clade. In his thesis, Timaná (2005) depicted a representative of this species in an ITS tree in a lineage with Pycnophyllopsis cryptantha and P. weberbaueri , thus supporting this position. However, these phylogenetic results cannot be reproduced because the sequences are not available and the tree was never properly published.

There are two specimens at SGO (old herbarium number 048875 corresponding to barcode SGO000001980 and old herbarium number 090982 corresponding to barcode SGO000001981 ) that were apparently collected by Philippi from the same locality, but the latter lacks a date.