Stellaria weberbaueri (Muschl.) 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

20. Stellaria weberbaueri (Muschl.) Montesinos & Borsch , comb. nov.

≡ Pycnophyllum weberbaueri Muschl. in Bot. Jahrb. Syst. 45: 455. 1911 = Plettkea weberbaueri (Muschl.) Mattf. in Schriften Vereins Naturk. Unterweser, n.s., 7: reprint p. 19 (23). 1934 ≡ Pycnophyllopsis weberbaueri (Muschl.) Timaná in Monogr. Syst. Bot. Missouri Bot. Gard. 127: 1271. 2014.

– Lectoype (designated here): Peru, Vincocaya, statio viae ferreae ad Arequipam , 4100 m, 24 Aug 1902, A. Weberbauer 1373 ( MOL [ MOL 00000507 !]) . – Fig. 1G .

Morphological description — See Timaná (2005).

Distribution — The species inhabits highland plateaus, also known as subnival puna, at altitudes of 4660– 5000 m. It is known to occur in the Arequipa and Moquegua departments of Peru, while its occurrence in the Bolivian Andes is not confirmed.

Notes — The species was first described as Pycnophyllum weberbaueri Muschl. by Muschler (1911), presumably based on the cushion growth form, plicate leaves and apical flowers. Later, the species was transferred to the genus Pycnophyllopsis by Timaná (2017), as Pycnophyllopsis weberbaueri (Muschl.) Timaná , based on the consistently pentamerous flowers with three free styles. Muschler (1911) apparently described characters for Stellaria weberbaueri such as true petals, which are actually not present in the specimens examined. Moreover, S. weberbaueri has leaves that do not overlap to be completely imbricate, giving the general impression of a loose cushion with longer internode length. Sharples & al. (2021) reported “ Stellaria weberbaueri (Muschl.) M. T. Sharples & E. A. Tripp ” in their Appendix 2, but this name has not been validly published anywhere.

Figures

Fig. 1 (p. 120). Habit in natural environment of some species of the Plettkea clade of Stellaria. – A: S. alpamarcae, Huánuco, Huamalies, 4400 m (Montesinos 5487, CAR440); B: S. congesta, Huánuco, Huamalies, 4200 m (Montesinos 4900, CAR661); C: S. galianoi, Cusco, Urubamba, near Malaga pass, 4240 m, shady rocky slopes in moist grasslands (Montesinos & von Mering 4523, CAR677); D: S. macbridei, Huánuco, Lauricocha, 4790 m (Montesinos 4590, CAR630); E: S. pedunculosa, Moquegua, near Ticsani volcano, 4818 m, pumice slopes (Montesinos & Chicalla 5395d, CAR777); F: S. utcubambensis, Amazonas, Chachapoyas, Leymebamba, Tajopampa, 3700 m, rocky summits of recently burnt slopes (Montesinos & Garcia 4979, CAR433); G: S. weberbaueri, Arequipa, 4876 m, forming cushions with eventually elongated stems (Montesinos & von Mering 4496, CAR670); H: S. xanthophylla Amazonas, S Leymebamba, 3540 m, forming dense mats (Montesinos 6970a, CAR691). – All photographs by Daniel B. Montesinos-Tubée.