Leucheria peteroana Lavandero, 2024

Lavandero, Nicolás, Pérez, Fernanda & Pinilla, Nicolás, 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, pp. 315-337 : 315-337

Leucheria peteroana Lavandero sp. nov.

Figs 3 , 4

Diagnosis.

Leucheria peteroana is most similar to Leucheria runcinata but differs by its simple aboveground stems (vs. branching stems), solely glandular indumentum (vs. lanose and glandular), lack of any type of scent (vs. strongly pungent or fetid odour), completely white corollas on the adaxial side (vs. lilac to blue), pink-purplish anther apical appendages (vs. blue), pink style branches (vs. white styles), and pappus pectines of 250–520 µm long (vs. 130–160 µm) (Figs 5 , 6 ). Leucheria peteroana also differs from Leucheria apiifolia by its larger height (vs. plants not taller than 30 cm.), two types of glandular trichomes in the vegetative part (vs. only one type of glandular trichome), lack of any type of scent (vs. soft and lemony odour), completely white corollas on the adaxial side (vs. pale gold corollas), outer lip completely extended at full anthesis (vs. outer lip revolute), and pink-purplish anther apical appendages (vs. beige to dark brown) (Fig. 7 ).

Type.

Chile • Región del Maule: Provincia de Curicó, comuna de Romeral. Lagunas de Teno, alrededores de la Laguna Planchón, sector Norte , 35 ° 10 ' 1.06 " S, 70 ° 32 ' 37.79 " W, 2593 m., 5 March 2019, fl. And fr., N. Lavandero, L. Santilli y C. Ossa 1873 (holotype: SGO 171859 !; Isotype CONC!) .

Description.

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. 1 mm 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 glandulous 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; venation prominent 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 a single corymbiform cyme per stem. Capitula 5–9 per stem, pedunculate, homogamous, discoid; pedicels (2 –) 8–10 (– 14) cm long. Involucres hemispheric 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, margin ciliate, 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 colour, 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.

Distribution and habitat.

Leucheria peteroana is endemic to the Andes of Central Chile. It is known only from the type locality on the whereabouts of Laguna El Planchón, Maule Region (Fig. 1 ). It grows at full sun in margins of Andean wetlands or shaded by large boulders and rock walls near 2500 m a. s. l. with SE orientation (Fig. 4 ). L. peteroana occurs 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.

Phenology.

Flowering between December and March. Fruiting in March.

Etymology.

The specific epithet refers to the active volcanic complex Planchón-Peteroa. The Andean Lake where the species occurs lies at the foot of this volcano.

Informal conservation status.

Leucheria peteroana can be tentatively considered as Critically Endangered (CR) under the IUCN categories and criteria B 2 ab (ii, iii). Criterion B 2 was selected because its Area of Occupancy is <10 km 2 (4 km 2). Criterion “ a ” was selected because it is known to exist at only a single location, with only two known subpopulations. Criterion b (ii, iii) was selected because we expect a continuing decline of suitable conditions for the species to thrive. There is evidence of a decreasing snow cover extent during the dry season of near 15 % per decade in the Andes at mid-latitudes ( Cordero et al. 2019). It is also likely that explosive volcanic eruptions of the Planchón-Peteroa complex, close to the only known locality of the species, may wipe out the whole population. These events are relatively common, with at least 20 eruptions documented since 1600 CE, the most recent occurring between September 2018 and April 2019 ( Romero et al. 2020). Leucheria peteroana is not present in any known protected area. Although there have not been appropriate efforts to exhaustively locate more populations of L. peteroana in the area, it is likely that these would be subject to the same threats as the already known populations. The extent of occurrence (EOO) could not be calculated since only two populations are known.

Additional specimens examined.

Chile • Región del Maule: Provincia de Curicó, departamento de Curicó. A Orillas de la Laguna Teno . 2500 m. 10 March 1967. Marticorena & Matthei 892 ( CONC!) ; En los alrededores de la Laguna Teno . 2570 m. Lavandero & Pérez 1504. 8 January 2022 ( SGO!) .

Notes.

Crisci (1976) and posteriorly Katinas et al. (2022) identified Marticorena & Matthei 892 as Leucheria apiifolia . The differences between these species are notorious (Fig. 7 ), since the leaf shape and flower colour differ, but the fact that both plants lack lanate indumentum and the dark colour both species acquire once pressed, may have led to this misidentification.

Figures

Figure 1. Distribution map of Leucheria peteroana (white triangles) in Chile, Maule Region, based on the type locality and collections.

Figure 3. Leucheria peteroana Lavandero, sp. nov. (Lavandero & Pérez 1504, SGO) A habit B detail of the capitulum, apical anther appendages and styles C capitulum, mid-upper view D capitulum, lateral view E leaf, abaxial side F leaf, detail of adaxial side G leaf, detail of abaxial side. All photographs by Nicolás Lavandero.

Figure 4. Habit and habitat of Leucheria peteroana Lavandero, sp. nov. A overview of Laguna El Planchón and the volcanic complex Planchón-Peteroa B detail of the plant C another plant, growing among rocks D detail of plant clump at full sun exposure, but right next to an Andean spring. All photographs by Nicolás Lavandero.

Figure 5. Comparison between Leucheria peteroana (NL- 1873, SGO) (A, C, E) and Leucheria runcinata (NL- 1867, SGO) (B, D, F) A, B frontal view of capitula C, D detail of capitula and flowers E, F cypselae and detail of pappus bristles. All photographs by Nicolás Lavandero, except E and F (Nicolás Pinilla).

Figure 6. Leaf morphology comparison between Leucheria peteroana and Leucheria runcinata. For each leaf, both adaxial and abaxial sides are shown A Leucheria peteroana, adaxial side (NL 1873, SGO) B Leucheria peteroana, abaxial side (NL 1873, SGO) C Leucheria runcinata, adaxial side (NL- 1867, SGO) D Leucheria runcinata, abaxial side (NL- 1867, SGO).

Figure 7. Other Leucheria species found along the Río Teno Basin in the Maule Region, Central Chile A Leucheria amoena B Leucheria apiifolia C Leucheria candidissima D Leucheria garciana E Leucheria glacialis F Leucheria integrifolia G Leucheria lithospermifolia H Leucheria millefolium. All photographs by Nicolás Lavandero, except L. amoena (Joaquín E. Sepúlveda) and L. candidissima (Guillermo Debandi).