Stellaria engleriana (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 : 132

6. Stellaria engleriana (Muschl.) Montesinos & Borsch , comb. nov.

≡ Arenaria engleriana Muschl. in Bot. Jahrb. Syst. 45: 449. 1911.

– Lectotype (designated here): Peru, Junín, Tarma , La Oroya , encima de Tarma en el camino a La Oroya , 4000 m, A. Weberbauer 2542 ( MOL [ MOL00000453 !]) .

Morphological description — Perennial herb, diffuse caespitose, cushions 5–12 cm in diam.; root woody. Stems subwoody, lower parts clothed with a greyishgreen thick bark, or very minutely ridged-reticulated, prostrate, sometimes rooting at nodes, 3–6 cm long, internodes 0.1–0.5 mm long, glabrous or with sparse slightly yellowish-whitish pubescence, trichomes 1–2 mm long. Leaves opposite, sessile; lamina lanceolate or ovate or rarely linear-lanceolate, fleshy or rarely membranous, thick, apex acute or mucronate, 5–10 mm long and 2–5 mm wide, hirsute near base and midvein, margin slightly hairy, midrib prominent on underside. Plants bisexual-hermaphrodite. Flowers subsessile or on short up to 0.5 mm long, glabrous peduncles, terminal and axillary; perigynous, cylindrical-oblong, 3.5–4.5 mm long and 1–1.8 mm wide; calyx cylindrical-turbinate; sepals 5, imbricate, ovate-oblong, slightly involute, yellow, 3–4 mm long and 1–1.5 mm wide, glabrous on surface but margins densely ciliate, apex acute-attenuate, folded and forming a narrow cylinder that covers capsule; petals 5, strongly reduced, yellowish to translucent, ovate, apex obtuse, 0.8–1.2 mm long and 0.3–0.5 mm wide; stamens 4 or 5, episepalous, 1.8–2.1 mm long; ovary ovoid-turbinate, 0.4–0.7 mm long and 0.4–0.6 mm wide, style 3-fid, stigma aciculate. Capsule subglobose, dehiscent with six valves, ovate-oblong, 1.3–1.7 mm long and 1.2–1.5 mm wide, containing 2–4 seeds, these lenticular, 0.7–1 mm in diam.; testa dark brown, bearing brown tubercles.

Distribution — Central Peru, in Junín and Huánuco departments, at altitudes of 4000–4400 m.