Senecio beltranii P.Gonzáles & Montesinos, 2020

Montesinos-Tubée, D. B. & Gonzáles, P., 2020, Senecio beltranii (Asteraceae, Senecioneae): a new caespitose species endemic to South Peru, Blumea 65 (2), pp. 162-166 : 162-166

Senecio beltranii P.Gonzáles & Montesinos , sp. nov. — Fig. 1 , 2

Differs from the most resembling Senecio algens Wedd. from the Central Andes,but differs in the following characters: matt-forming subshrub (against procumbent herb in S. algens ), the presence of scattered papillose trichomes (0.05–0.15 mm long) on stems and leaves (glabrous in S. algens ), leaf margin shape (pinnatilobate vs entire), pedicel length (12–18 mm vs 8–12 mm), involucre length (12–15 mm vs 7.5–10 mm), calycular bracts (nearly glabrous vs glabrous), phyllary length (9–11 mm vs 7–9 mm), phyllary width (1.9–2.1 mm vs 2–3 mm) and by the larger number of phyllaries (18–22 vs 10–15). — Type: D.B. Montesinos 5150 (holo HSP;iso B, CUZ,F, HUT, LP), Peru, Arequipa,Caylloma,Chivay,roadside along Abra Apacheta, S15°43'12" W71°36'10", 4800 m, 27 March 2017 .

Etymology. The specific epithet refers to the Peruvian botanist Hamilton Beltrán Santiago (1963) to honour his contributions to the knowledge of the Andean flora.

Perennial subshrub, caespitose, creeping, rhizomatous, with fibrous roots, forming mats 2–4 cm tall and 5–30 cm diam. Trichomes almost absent except for a few papillose trichomes on stems and leaves, 0.05–0.15 mm long, apex rotund. Stems woody, 1–2 cm by 3–4 mm, often covered with persistent re- mains of senescent leaves towards the base. Cauline leaves spathulate-oblanceolate, alternate, 2–3 cm long; lamina thick, lustrous, involute, curved, 8–12 by 2–4 mm, pinnatilobate (den- ticles 5–7, triangular, 0.5–0.8 mm wide), margin and surfaces glabrous except for a few papillose trichomes of about 5–15 μm long, apex obtuse-acute, base truncate to rounded, margin entire; young leaves pale greenish grey turning yellowish brown with age. Synflorescence a solitary capitulum, homogamous, discoid; peduncle 5–12 mm long, reddish purple to plum-purple; pedicels 12–18 mm long, margin with few trichomes of 0.05–0.15 mm long, base truncate; involucre cylindrical, 12–15 mm long, 7–9 mm wide. Calycular bracts linear-oblong, 6–9 by 0.8–1.1 mm, scarcely covered with thin, 0.05–0.3 mm long papillose trichomes on the margin and surface, surface and margins pale green except for the reddish purple to plum-purple coloured midrib, apex covered with 10–20 μm long glands. Phyllaries 18–22, oblong, 9–11 by 1.9–2.1 mm, apex acute, surface and margins pale green to reddish purple, midrib reddish purple, glabrous except for 0.1–0.3 mm long transparent trichomes at the apex. Florets 44– 54, tubular, abruptly constricted near the base, pale yellow; corolla lobes 5, triangular, 0.8–1 mm long; tube 6–8 by 0.3–1.2 mm. Anthers oblong, 6–7 by 0.2–0.3 mm, ecalcarate, terminal appendages oblong, rounded, pale reddish purple with yellowish margin. Style truncate, 8–12 mm long, apex bifid (branches 0.8–1.3 mm long, curved), with papillae covering the whole surface of the apex, pale yellow turning bright yellow towards the apex. Receptacle flat, epaleate, 2–3 mm diam. Achenes cylindrical-conical, 0.8–1.2 by 0.3–0.4 mm, glabrous, light brown. Pappus of smooth bristles, 5–7 mm long, white, barbellulate.

Distribution — Senecio beltranii is reported from the northern Arequipa region at the boundary with southern Cusco region (South Peru) and the Cordillera of Vilcanota, in the basin of Laguna Sibinacocha. Elevation range: 4700–5470 m.

Habitat & Ecology — Senecio beltranii occurs on highland puna and subnival puna slopes with scattered rocks and cushion plants. It co-occurs with Pycnophyllum molle J.Rémy ( Caryophyllaceae ) and Azorella compacta Phil. ( Apiaceae ). Flowers and fruits were observed between March and May.

Conservation status — Following the criteria and categories of IUCN (2019), a preliminary status of Vulnerable (VU) is recommended, since the isolated populations observed are estimated to be in a geographic range of <5 000 km 2. The suitable habitats for S. beltranii are the large plateaus above 4 700 m north of the Arequipa region and south of the Cusco region and dangers such as volcanic activity, road construction, and the exploitation of natural resources can lead to the gradual disappearance of the species.

Additional material examined (paratypes). PERU, Arequipa, Caylloma, Chivay, roadside along Abra Apacheta , S15°43'33" W71°35'18", 4738 m, 28 Mar. 2016, D.B. Montesinos 4553 (B, HSP) ; Cusco, Espinar, Condoroma, 5 km offroad from Condoroma , S15°14'34" W71°08'28", 4850 m, 15 Mar. 2018, P.Gonzáles & E. Huamán 4254 (USM) ; Cusco, Cordillera de Vilcanota, cuenca de la laguna Sibinacocha, cerro Yurak , S13°46'00" W71°05'16", 5470 m, 8 Mar. 2019, R.I. Meneses, H. Alberto, A. Lliully, K. Yager, V. Urrelo, F. Velarde, M. Jihuallanca, J. Villalobos & R. Azócar 7028 (LPB) .

Figures

Fig. 1 Senecio beltranii sp. nov. a. Capitulum; b. phyllaries (complete form and apex); c. floret with pappus and achene; d. calycular bract;e. stamen; f. stamens arrangement; g. achene; h. leaves (adaxial and abaxial views); i. style (with detail of apex of style branch) (all: D.B. Montesinos 5150, HSP). Drawing by Delsy Trujillo.

Fig. 2 Senecio beltranii. a. Plateaus along Abra Apacheta (4800 m) in Arequipa showing the habitat; b. habit showing relative size; c. capitulum; d. branch with leaves and one capitulum. — Photos a, b, d by Daniel Montesinos; c by Paúl Gonzáles.