Valeriana plateadensis A. J. Perez, C. Persson & J. N. Zapata 2023, sp. nov.

1. Valeriana plateadensis Á.J. Pérez, C. Persson & J.N. Zapata, sp. nov. — Figures 1 A–C, 2 A–E

Type: ECUADOR. Zamora-Chinchipe: Cantón Nangaritza, Parroquia Nuevo Paraíso. Reserva Biológica Cerro Plateado, [la cima de la meseta], -4.6194445, -78.7830556, 2900 m, 8 August 2021 (fl), A. J. Pérez, N. Zapata, T. L. P. Couvreur, C. Persson, R. Paqui, R. Cabrera & W. Santillán 11704 (holotype QCA-244410; isotypes GB-0210405, PRC).

Shrub 20–25 cm tall with ± erect branches. Stem and branches terete covered with dead leaves basally, 0.5 to 1 cm wide (incl. leaves), slightly wider at the head-like top, branching rhythmic with 3–7 branches at each node. Leaves seemingly spirally arranged (but actually positioned in multiple ranks) and overlapping, sessile, glabrous, coriaceous, spatulate and sharply bent, proximal portion canaliculate, 5 × 1 mm, adpressed tightly to the shoot, distal portion widely oblong 2.1–2.3 × 2–2.2 mm, with rounded apex, above slightly concave with thickened margin, below sometimes with a raised narrowly triangular portion, fresh leaves generally spreading (forming an angle of 90° to the shoot), or in the uppermost portion of the shoots ascending to erect, dried and dead leaves the outer portion generally facing downwards. Inflorescence a loose cluster of up to 12 flowers at the top/end of the shoots, partial inflorescences of 2–3 flowers subtended by an opposite pair of involucral bracts that are entirely or fused in for 2/3. Flowers hermaphrodite? (neither pollen nor ovules seen); calyx vestigial; corolla funnelform, white, 3-lobed, the tube obconical, 3–3.5 mm long, 0.2 to 1.5 mm wide, the lobes widely ovate, ca 1.5 × 1 mm, apex obtuse; stamens 3, exserted, the filaments white, flattened, 2.5 mm long, inserted in the upper portion of the tube, anthers 0.2 × 0.1 mm; style slightly exserted, the stigma capitate, the ovary cylindrical 0.7 × 0.3 mm, glabrous with 1 pendent ovule. Fruits unknown.

Additional specimens examined: ECUADOR. Zamora-Chinchipe, Nangaritza, Cordillera del Cóndor, Reserva Biológica Cerro Plateado, gently sloping summit area of Cerro Plateado, 4°37’10” S, 78°46’59” W, 2915 m, 24 August 2012 (fl), D. Neill, M. Asanza & E. Cueva 17494 (ECUAMZ); en la cima de la meseta, -4.6194445, -78.7830556, 2900 m, 23 September 2016 (fl), Á. J. Pérez, N. Zapata & W. Santillán 10175 (QCA-244424); 2850–2900 m, 27 September 2016 (fl), Á. J. Pérez, N. Zapata & W. Santillán 10329 (QCA-244532).

Valeriana plateadensis is distinguished from other Valeriana species of the high Andes with 3-lobed corollas by being small sparsely branched shrubs with small spatulate and sharply bent densely set leaves in multiple ranks.

Distribution and habitat:— Valeriana plateadensis is an endemic species to Cerro Plateado, Cordillera del Cóndor in southeast Ecuador where it has been collected on sandstone soil between rocks on the top of the Andean tepui at 2900 m (Figure 3A). Associated plants include Symplocos neillii Ståhl (2010: 86), Diplostephium sp. nov, Chusquea nana (Clark) Clark (2009: 681) and Drosera peruensis Silva & Correa (2002: 543) (Figure 3A).

Conservation status: Only one population with ca. 40 mature individuals of this species were discovered at the type locality at the summit of the Cerro Plateado. It is an isolated area and difficult to access; nevertheless, climate change effects could affect the distribution and population size of this species negatively. According to the IUCN Red List criteria (IUCN 2022) this species is therefore assessed as Vulnerable (VU, Criterion D2).

Phenology: Flowers were collected in August and September.

Etymology: The specific epithet of this species refers to Cerro Plateado in the Cordillera del Cóndor in southeastern Ecuador which is the only known locality for this species.