Miersia stellata C.Cuevas & Nic. Garcia, 2022

Garcia, Nicolas, Cuevas, Claudia, Sepulveda, Joaquin E., Cadiz-Veliz, Aron & Roman, Maria Jose, 2022, Two new species of Miersia and their phylogenetic placements alongside the recently described M. putaendensis (Gilliesieae, Allioideae, Amaryllidaceae), PhytoKeys 211, pp. 107-124 : 107

Miersia stellata C.Cuevas & Nic. Garcia sp. nov.

Figs 3 , 4

Diagnosis.

Miersia stellata differs from Miersia humilis (Phil.) M.F.Fay & Christenh. by a capitate stigma (vs. trilobed stigma), six bifid, rarely trifid, flat tepaliferous appendages (vs. tepaliferous appendages absent), and a cylindrical to urceolate staminal tube with a short apical reflexed rim (vs. staminal filaments fused in their basal half and covering the ovary, but not forming an urceolate tube).

Type.

Chile. Región Metropolitana de Santiago: Provincia de Chacabuco, Comuna de Lampa, cerro Quilhuica , 600 m a.s.l., 17 June 2021, N. García & C. Cuevas 6132 (holotype: EIF 14823 ; isotypes: CONC, JBN, SGO) .

Description.

Terrestrial saxicolous herbs. Bulbs ovoid, usually flattened due to growth in rock crevices, external cataphylls light brown, 11-15 × 5-10 mm. Leaves 2-3, linear, hanging, 7-20 × 0.09-0.2 cm. Scapes 1-2, cylindrical, hollow, 20-70 × 1-1.3 mm. Spathe 2-valvate, herbaceous, lanceolate, 7-12 × 1.5-2 mm, fused on their basal ¼ (~2.5 mm), whitish with veins inconspicuous or purple spotted. Inflorescences a pseudo-umbel with 1-2 (-3) slightly zygomorphic, star-shaped flowers; pedicels unequal, 1.4-2.7 cm long, apex curved in a right angle (~90°). Tepals 6, free, membranous, light green, rarely purplish, lanceolate, caudate, straight, outer 12 × 2-2.5 mm, 5 acrodromous veins, inner 11-11.5 × 1.5-1.8 mm, 3 acrodromous veins, on both whorls only the central is well marked and runs throughout the complete length, cauda 0.4-0.5 mm wide comprising ~2/3 of the tepal’s length. Tepaliferous appendages 6, green, deeply bifid, rarely trifid, flat, upper pair with lanceolate segments, each segment sometimes shortly bifid, fused at base ~0.6 mm, 2.0-2.5 × 0.4-0.5 mm, lateral appendages one pair on each side, with linear to linear-lanceolate segments, attached to the base of inner tepals, segments fused at base ~0.1 mm long, 2.0-2.5 × ca. 0.2 mm. Stamens 6, filaments 0.2-0.3 mm long, adnate internally to the staminal tube; staminal tube cylindrical to urceolate, whitish with two purple longitudinal stripes and three longitudinal folds on its upper side, single longitudinal fold on the lower side, apex with a short reflexed rim, papillose, 2.0-2.5 × 1.5-2.5 mm; anthers yellow (purple when dry), 0.8-1.0 mm long, exerted. Ovary superior, spherical to obovoid, 1.0-1.3 mm long, trilocular, 12 ovules per locule, biseriate; style nodding, exerted, 1.7-2.0 mm long; stigma capitate. Capsules obovoid to spherical, 3-valved, 4-8 × 4-6 mm. Seeds not seen.

Distribution and habitat.

Miersia stellata has been recorded in a single rocky outcrop in the Quilhuica hill, Lampa (~33.3° S), which is an isolated hill, between the main coastal mountain range (cordillera de la Costa) and the basin of Santiago. This south-facing rocky outcrop is at the bottom of a creek at 600 m a.s.l. The new species grows exclusively in rock crevices along with Tristagma graminifolium (Phil.) Ravenna. The surrounding vegetation corresponds to a degraded sclerophyllous arborescent scrub composed of Lithraea caustica (Molina) Hook. & Arn., Quillaja saponaria Molina and Porlieria chilensis I.M.Johnst.

Phenology.

This species has been seen in flowers between May and August. Immature fruits have been recorded during August and September; in general, fructification is low in the population.

Etymology.

The specific epithet Miersia stellata refers to star-shaped form of flowers.

Vernacular name.

Although no popular common name is known for Miersia stellata , we propose to name it " estrella de Lampa " or "Lampa star".

Conservation status.

Miersia stellata can be considered Critically Endangered (CR) according to criteria B2ab(iii). Its area of occupancy is <10 km2, with an estimate of 120 m2 (~0.0001 km2). Only a single population of <100 individuals has been recorded despite sampling efforts in surrounding areas in suitable seasons and habitats. In addition, it inhabits an area intensely degraded by human activities and is close to a highway with heavy traffic and to populated locations (Batuco, Lampa).

Additional specimens examined

(paratypes). Chile. Región Metropolitana de Santiago: Provincia de Chacabuco, Comuna de Lampa, cerro Quilhuica , 600 m a.s.l., 5 August 2020, C. Cuevas s.n. (EIF); 16 September 2020, N. García, C. Cuevas & M. Villalobos 5843 (EIF) .

Figures

Figure 3. Miersia stellata C. Cuevas & Nic. Garcia A front view of flowers B detail of flower showing tepaliferous appendages and staminal tube C lateral view of flower D immature fruit E habit F habitat. Scale bars: 5 mm (A, C); 2 mm (B). Photos by Nicolas Garcia (A, C, E, F), Nicolas Villaseca (B), Claudia Cuevas (D).

Figure 4. Miersia stellata C. Cuevas & Nic. Garcia A habit B flower (frontal view) C plant growing in its natural habitat D staminal tube (lateral view) E fruit (apical view) F fruit (lateral view). Illustration by Aron Cadiz-Veliz.