Peteroa daisy (Leucheria peteroana) endemic to the Andes of Central Chile at elevation of 2500 meters

NEWS - Peteroa daisy (Leucheria peteroana Lavandero sp. nov.) is endemic to a restricted area of the Andes of Central Chile, described based on nDNA and cpDNA with a series of unique characters that clearly distinguish it from other species.

Leucheria Lag. is one of the largest genera in the Nassauvieae and is distributed in Peru, Bolivia, Chile and Argentina, including the Falkland Islands. It is mostly found in the Patagonian-Andean and Subantarctic Phytogeographic domains.

The unusual Leucheria specimen was collected around Lagunas del Teno in the Andes in the Maule Region, Chile. This area is characterized by steep topography, with elevations up to 4112 m. This mountainous area of the Andes is characterized by active volcanic activity.

L. peteroana is a perennial herb 40–70 cm tall, forming clumps of seasonally persistent annual stems. Rhizome dark brown, round, 25–50 mm wide, bifurcating, oblique to vertical. Roots brown, ca. 1mm wide.

Stems green, erect, fistulose, 2.5–5.0 mm wide, simple, never branching, round, internodes up to 10 cm long, densely covered by two types of trichomes with clear and sticky resin, not fragrant, and without any pungent or noticeable scent when touched or pressed (same indumentum up to the corolla tube): short glandular, capitate, (60–)90–150 µm long, multicellular 8–15-celled trichomes; long glandular, (300–)500–1500(–2300) µm long, multicellular 10–30(–50)-celled trichomes.

Leaves green, alternate; basal leaves attenuate, more densely arranged at the base, but not forming a conspicuous rosette; upper leaves sessile, amplexicaul, loosely arranged, gradually reduced in size towards the capitulescence.

Lamina oblanceolate, pinnatipartite to pinnatisect, with 6–9 segments per side, almost tripartite towards the apex, (70–)130–180(–190) × (20–)50–60(–65) mm; base attenuate, amplexicaul, apex mucronate; margin serrate, texture coriaceous, densely glandular on both surfaces.

Segments at the base 1(–2)-dentate, apex mucronate; segments in the middle 4–7-dentate; apical segments fused, 3–7-dentate; prominent veins on abaxial side, with primary vein ending in apical mucro, secondary veins ending in apical mucro of each segment, and tertiary veins ending in lateral teeth of each segment.

Capitulescence of a single corymbiform cyme per stem. Capitula 5–9 per stem, pedunculate, homogamous, discoid; pedicels (2–)8–10(–14) cm long. Hemispheric involucres 10.1–11.0 × 14.2–15.2 mm, two-seriate, alternate. Receptacle convex, epaleate (no flowers between bracts), glabrous.

Outer involucral bracts (10–)12(–14), green, lanceolate, concave on the inner face, 8.1–9.2 × 1.8–1.9 mm, with 3 dark-green longitudinal veins (including the midrib), margin ciliate, apex ciliate , texture coriaceous to hyaline-membranaceous towards the margins, abaxial side densely covered by short and long glandular trichomes, adaxial side glabrous.

Inner involucral bracts half the number of outer involucral bracts, (5–)6(–7), green, lanceolate, concave to flat 9.0–9.2 × 1.9–2.2 mm, with one dark-green longitudinal stripe (midrib), apex acute , texture leaf-like to hyaline-membranaceous towards both lateral margins, ciliate margin, central portion of the abaxial side sparsely covered by short glandular trichomes, hyaline lamina glabrous, adaxial side glabrous.

Flowers isomorphic, bisexual, (40–)43(–45) per capitulum. Corollas bilabiate, white, sometimes pinkish white on the abaxial side, tube 4.3–4.6 mm long, 1.0–1.1 wide; corolla tube sparsely covered by glandular trichomes.

Outer lip oblanceolate, 6.8–7.1 × 3.2–3.5 mm at its widest, apex 3-toothed, teeth equal, 4-veined, glabrous. Inner lip bifid, lacinae linear, 3.4–3.6 × 0.20–0.29 mm at its widest, connivent, glabrous. Stamens 5, 6.2–6.7 mm long, glabrous.

Anthers sagittate, 3.0–3.3 mm long; apical appendages pink-purplish, lanceolate, 1.6–1.9 mm long, apex acute; tails long, lanceolate, 1.1–1.2 mm long, apex rounded, smooth. Style pink, 6.5–7.0 mm long, cleft into two truncate branches of pink color, branches 1.1–1.3 mm long, with stigmatic papillae on internal surface and apical crown papillose.

Cypselae dark-brown, 3.5–3.6 × 1.1–1.2 mm, obovoid, strigose; covered by two types of trichomes: glandular biseriate trichomes, 100–130 µm long, and twin trichomes, 230–280 µm long. Pappus uniseriate, fused at their bases into a ring, deciduous; bristles 23–30, white, sub-plumose, 7.4–7.7 mm long; pectines long, filiform, 250–400(–520) µm long, laterally inserted.

L. peteroana is most similar to L. runcinata but differs in simple aboveground stems (vs. branched), only glandular indumentum (vs. lanose and glandular), no scent (vs. pungent or putrid), completely white corolla (vs. purple to blue), apical appendages of anthers purplish pink (vs. blue), pistil branches pink (vs. white), pectin pappus 250–520 µm (vs. 130–160 µm).

L. peteroana also differs from L. apiifolia in being taller (vs. no more than 30 cm tall), two types of glandular trichomes in the vegetative part (vs. one type), no aroma (vs. mild lemon-like odor), completely white flower crowns ( vs. pale gold), the outer lip is fully open at full anthesis (vs. recurved), and the apical appendages of the anthers are purplish pink (vs. cream to dark brown).

The new species is endemic to the Andes of Central Chile and is known only from the type locality around Laguna El Planchón, Maule Region. It grows in full sun on the edge of Andean wetlands or in the shade of boulders and rock walls near high elevations. 2500 m with southeast orientation.

L. peteroana is associated with other high Andean plants such as Grausa lateritia (Gillies ex Arn.) Weigend & R.H. Acuña, Calceolaria williamsii Phil., Acaena ovalifolia Ruiz & Pav., Calceolaria filicaulis Clos, and Erythranthe lutea (L .) G.L. Nesom.

Flowers between December and March and bears fruit in March. The specific epithet refers to the active volcanic complex Planchón-Peteroa. The Andean lake where this species occurs is located at the foot of this volcano. The new species can be considered as Critically Endangered (CR) because the Area of Occupancy is less than 10 km2.

Original research

Lavandero N, Pérez F, Pinilla N (2024). Leucheria peteroana (Nassauvieae, Asteraceae), a new species of Leucheria endemic to the Andes of Central Chile, and insights into the systematics of Nassauviae. PhytoKeys 248: 315-337, DOI:10.3897/phytokeys.248.133202

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