Justicia darienensis T.F. Daniel & M. Vargas P., 2024

Justicia darienensis T.F. Daniel & M. Vargas P. View in CoL , sp. nov. ( Figs. 1–4 View FIG View FIG View FIG View FIG ). TYPE. PANAMA. Darién: Reserva Natural Privada

Cerro ChucantÍ, sendero de los helicopteros, a la orilla del camino, 08°47′45″N, 078°27′47″W, 1300 m, 3 Dec 2016 (flr), M. Vargas GoogleMaps ,

Z. Mijango & I. Arcía 187 (HOLOTYPE: PMA!).

Justicia darienensis is superficially similar to J. costaricana Leonard , but differs from that species by its complex inflorescence structure (vs. simple spikes), longer (15–18 vs. 10–14 mm) corollas, apically rounded to truncate (vs. apiculate) fertile bract apices,stationary (vs.laterally diverging) stamens at maturity,glabrous anther thecae (vs.dorsally pubescent upper anther thecae), and 4-aperturate (vs.2-aperturate) pollen.

Terrestrial herbs to ca. 1 m tall. Young stems quadrate to quadrate-sulcate, glabrous. Leaves petiolate, petioles to 37 mm long, pubescent (especially adaxially) with flexuose to antrorse eglandular trichomes, blades ovate to ovate elliptic, 80–125 mm long, 35–68 mm wide, length:width = 1.8–2.3, ± rounded to cuneate at base, acute at apex, adaxial surface pubescent (mostly along midvein) with antrorse eglandular trichomes, abaxial surface very sparsely pubescent along major veins with similar trichomes, superficial cystoliths prominent. Inflorescences of terminal modified panicles or panicle-like thyrses consisting of modified spicate branches (= dichasia?, see discussion below) from axils of distal leaves and/or bracts (?; caducous and not seen) to 65 mm long and 27 mm in diameter (measured flat), rachis pubescent with coarse, mostly antrorse to antrorsely appressed eglandular trichomes to 0.5 mm long; axillary spicate branches (= modified dichasia?) opposite along rachis, sessile to pedunculate (?), multi-flowered, expanded at only one node per flower, branches (= secondary peduncles?) pubescent like rachis. Bracts at branch (= dichasial?) nodes heteromorphic, narrowed proximally into a stalklike base, fertile bracts obovate to spatulate to obdeltate, 8–12 mm long, 2–4 mm wide, rounded to truncate at apex, abaxial surface pubescent with sparse eglandular trichomes 0.1–0.2 mm long and also with mostly subsessile glandular trichomes less than 0.1 mm long, margin ciliate with erect to flexuose eglandular trichomes to 0.8 mm long and also with stipitate glandular trichomes to 0.2 mm long, sterile bracts narrowly oblanceolate to narrowly spatulate, 3.5–5 mm long, 0.2–0.5 mm wide, pubescent like fertile bracts or lacking glandular trichomes. Bracteoles subtending flowers narrowly spatulate and often asymmetric, 9–9.5 mm long, 1–1.4 mm wide, pubescent like subtending bracts. Calyces deeply and subequally 5-lobed, 5–6 mm long, lobes lanceolate, 4–5 mm long, 0.5–0.8 mm wide, abaxially pubescent with flexuose to antrorse eglandular trichomes 0.1–0.3 mm long, margin whitish-green, ciliate with flexuose eglandular trichomes to 0.5 mm long. Corollas white with purple discolorations in a herringbone pattern internally on lower lip and with greenish tinge internally on upper lip, 15–18 mm long, externally pubescent with flexuose to retrorse eglandular trichomes 0.2–0.5 mm long, tube 9.5–12.5 mm long, 1.8–2.5 mm in diameter (measured flat) at base, 2.5–3 mm in diameter (measured flat) at mouth, expanded distally into an obconic throat, narrow proximal portion 6–8 mm long, throat 3–6 mm long, upper lip erect, 3–4.5 mm long, shallowly 2-lobed at apex, lower lip spreading at 90° to upper lip, 3-lobed, 4.5–6 mm long, lobes obovate, 4–5 mm long, 1.7–2 mm wide. Stamens inserted near base of throat, 4–7 mm long, filaments glabrous, thecae unequally inserted (overlapping by 0.6–0.7 mm), subparallel to slightly offset, 1.3–1.5 mm long, glabrous, lower theca with a thick basal appendage 0.2 mm long. Pollen euprolate, 4-colporate, 8-pseudocolpate, polar diameter (P) 38–46 µm, equatorial diameter (E) 24–28 µm, P:E = 1.4–1.8, interapertural exine bireticulate. Styles 13.5–15 mm long, glabrous, stigmas ca. 0.1 mm long, lobes not evident. Capsules 10.5 mm long, pubescent with eglandular trichomes. Seeds 4, discoid, 2–3 mm long, 2–2.6 mm wide, surfaces smooth.

Phenology.— Flowering: December–January; fruiting: January.

Distribution, habitat, and threats.— Endemic to the Majé Mountains in northwestern Darién Province of eastern Panama ( Fig. 3 View FIG ); plants were collected in cloud forest at 1300–1390 meters elevation in the Reserva Natural Privada Cerro ChucantÍ. Cerro ChucantÍ is the only area within the SerranÍa de Majé covered predominantly by cloud forest at higher elevations. It is isolated from the nearest equivalent cloud forest in the Cerro Pirre by ca. 120 km of lowland terrain, and thus it is sometimes referred to as a tropical sky island. At least 18 new species of plants, invertebrates, and vertebrates that are known only from the Cerro ChucantÍ have recently been described (e.g., see articles listed at: http://adoptabosque.org/en/chucanti/new-species/). Although tropical cloud forests have promoted the evolution of endemic species, and some have high levels of biodiversity and endemism, they are threatened by human disturbance, including global warming (e.g., Bubb et al. 2004; Karger et al. 2021). Indeed, the montane rainforest of the lower slopes of Cerro ChucantÍ face threats from agriculture, logging, and cattle ranching ( Batista et al. 2020).

PARATYPE.— PANAMA. Darién: Reserva Natural Privada Cerro ChucantÍ, área cercana al Campamento del Filo , 08°48′16″N, 078°27′34″W, 28 Jan 2023 (flr, frt), L GoogleMaps . Guillén , J . Guerra , M . Lino & G . Fatacioli 801 ( PMA) .