Senecio phlomidifolius H. Beltrán, 2021

Beltrán, Hamilton & Calvo, Joel, 2021, Two new species of Senecio (Compositae, Senecioneae) from Peru, Phytotaxa 479 (2), pp. 198-204 : 199-200

1. Senecio phlomidifolius H. Beltrán , sp. nov. ( Fig. 1 )

Type: — PERU. Lima: Yauyos, Laraos, Carhuanisho , 12º22’58’’S 75º38’10’’W, 4932 m, 4 June 2017, H . Beltrán 8082 (holotype: USM 310142 ) .

Senecio phlomidifolius differs from other related species of the genus (see discussion below) in its long-pseudopetiolate basal leaves covered with laxly lanate indumentum, discoid, nodding, short-pedunculate capitula arranged in lax racemose-corymbs, and glabrous achenes.

Perennial, rhizomatous herb, up to 40 cm tall. Rhizomes 5–7 × ca. 0.8 cm, barely branched, covered by sheath-like leaf base remnants. Basal leaves in pseudorosette, persistent, 20–24 cm long; laminas 10–12 × 2.5–3 cm, elliptic to oblong-elliptic, rather obtuse at the apex, attenuate at the base, denticulate, revolute, pinnately veined with 6 to 9 conspicuous nerves per side, laxly lanate on both faces; pseudopetioles 8–11 × 0.4–1.3 cm, sheathing toward the base, with ca. 12 nerves, laxly lanate. Cauline leaves alternate, sessile, decreasing in size upward; laminas 8–10 × 0.7–2.5 cm, oblanceolate to lanceolate, rather obtuse at the apex, obtuse at the base (barely decurrent), distantly denticulate, slightly revolute, pinnately veined with 5 to 7 nerves per side, laxly lanate on both faces. Synflorescences racemosecorymbose, terminal, lax. Capitula 4 to 5, discoid, nodding, shortly pedunculate; peduncles up to 2 cm long, with linear, 14–16 × 1.5–2 mm bracteoles, lanate. Involucres 1.4–1.8 × 1.5–2 cm, campanulate to cupuliform; involucral bracts 24 to 26, ca. 10 × 1.5–2 mm, linear to oblong-lanceolate, acute at the apex, with broadly scarious margins, abaxially lanate, adaxially glabrous. Supplementary bracts (calyculus) 18 to 22, 9–10 × ca. 1 mm, linear-subulate, 2 to 3-seriate, rather lanate, usually purple near the apex. Florets 150 to 160, 9– 10.1 mm long, hermaphroditic, tubulose, glabrous, dark-yellowish toward the apex; tubes 5–5.6 mm long, somewhat swollen at the base; limbs 4–4.5 mm long, cylindrical, 5-lobed, with triangular, somewhat incurved, ca. 1.5 mm long lobes. Anthers 3–3.5 mm long, yellow; anther appendages ca. 0.4 × 0.2 mm, purple; anther bases auriculate; filament collars 0.6–1 mm long, balusterform. Style branches ca. 2 × 0.25 mm, truncate with a crown of sweeping hairs of different length.Achenes 1.7–1.9 mm long, cylindrical, glabrous (immature); pappus ca. 10 mm long, barbellate, whitish (immature).

Distribution and habitat: — Peru (Lima). This species is only known from the type locality in the Laraos District at ca. 5000 m ( Fig. 2 ). It grows in rocky places on consolidated soils, usually under the protection of rocks. Some species that were observed in the same habitat are Dielsiochloa floribunda (Poaceae) , Englerocharis peruviana (Brassicaceae) , Nototriche tovarii (Malvaceae) , Senecio canescens , S. carhuanishoensis , S. nutans , S. rufescens , S. violifolius , and Xenophyllum ciliolatum (all Compositae).

Phenology: —Collected in flower in early June.

Etymology: —The epithet phlomidifolius refers to the resemblance of the leaves to those of some species of Phlomis (Labiatae) .

Discussion: —Due to the habit, indumentum type, and capitulum morphology, S. phlomidifolius is morphologically close to S. ellenbergii Cuatrecasas (1960: 187) and S. roseoandinus Montesinos & R.Zárate in Montesinos et al. (2018: 219). From S. ellenbergii , known from Cajamarca, the new species differs in shape and length of the basal leaf lamina (elliptic to oblong-elliptic, 10–12 cm vs. broadly lanceolate, 5.5–7 cm in S. ellenbergii ), peduncle length (shortpedunculate, up to 2 cm vs. long-pedunculate, 2–9.5 cm in S. ellenbergii ), number of supplementary bracts (18 to 22 vs. 14 to 18 in S. ellenbergii ), number of florets (150 to 160 vs.> 200 in S. ellenbergii ), floret length (9–10.1 mm vs. 6–7.5 mm in S. ellenbergii ), and achene indumentum (glabrous vs. densely thick-pilose in S. ellenbergii ). Their distribution areas do not overlap. Regarding S. roseoandinus , the new species can be distinguished by the leaf indumentum (laxly lanate on both surfaces vs. glabrous to densely arachnoid above, densely lanate beneath in S. roseoandinus ), cauline leaf size (8–10 × 0.7–2.5 cm, progressively decreasing in size upward vs. 1–6.5 × 0.4–1.5 cm, abruptly decreasing in size upward in S. roseoandinus ), number of florets (150 to 160 vs. 120 to 130 in S. roseoandinus ), and corolla length and color (9–10.1 mm, dark-yellowish vs. 5–8 mm, pink-reddish when mature in S. roseoandinus ). Senecio roseoandinus is only known from the type locality in northwestern Huánuco Department.

Senecio phlomidifolius also might be confused with S. keshua Cabrera (1966: 12) , a species with pseudopetiolate basal leaves, lanate indumentum, and few nodding capitula. They can be differentiated by the indumentum type, which is densely lanate in S. keshua but laxly lanate in S. phlomidifolius . Their distributions areas do not overlap; S. keshua is known from northern Chile and northwestern Argentina ( Salomón et al. 2018) and its presence in Bolivia is likely ( Beck & Ibáñez 2014, sub the heterotypic synonym S. zoellneri ).

Finding further populations of S. phlomidifolius is essential in order to improve the knowledge of its variability and distribution area.

Figures

FIGURE 1. Seneciophlomidifolius.A.Habitat.B. Habit.C.Abaxialand adaxial basal leafsurface (from left).D.Capitula.E.Supplementary bracts. F. Involucral bracts. G. Floret. H. Limb lobes. I. Anthers and filament collars. Pictures by H. Beltrán.

FIGURE 2. Distribution maps of Senecio phlomidifolius (red cross) and S. fernandinus (open circle).