Eschweilera donosoensis J. E. Bat. & S.A.Mori

Description

Author: Juvenal E. Batista & S.A. Mori

Type: Panama. Colón, Distrito de Donoso, Botija, 8° 50' 12" N, 80° 38' 41" W. 117 m, 19 May 2015, J. Batista et al. 1368 (holotype, PMA!; isotypes, MO!, NY!, UCH!, SCZ!).

Description: Understory to subcanopy trees 7–20 (–25) m × 19.2–25 cm, buttresses < 1 m tall. Bark dark-brown, scalloped, lenticellate, the outer bark thinner than inner bark. Leaves: petioles 3–9 mm long, canaliculate adaxially; blades elliptic, 3.2–19.7 × 1.5–8.4 cm, chartaceous, glabrous, with inconspicuous reddish punctuations abaxially (visible with hand lens) the base obtuse to rounded, the margins entire to crenulate, the apex acuminate to attenuate; secondary veins in 8–12 pairs, plane adaxially. Inflorescences from branches below leaves (ramiflorous), axillary, or terminal (suprafoliar), unbranched, the rachis 1–6 cm long, puberulous (at flowering), glabrous (at fruiting), sparsely lenticellate; pedicel/hypanthium 6–7 mm long., slightly tapered to articulation, puberulous, sparsely lenticellate. Flowers 2–4 cm diam.; bract ovate-triangular, 1.5–2 mm long, bracteoles elliptic, 3–3.5 mm long, deciduous, hypanthium puberulous, tapered to articulation; calyx lobes 6, ovate, 4.5–6 × 3–4 mm, not imbricate, carinate at base, horizontally oriented at anthesis; petals 6, 15-28 × 12-14 mm, white or pale yellow; ligule yellow, 15–25 mm long, androecial hood yellow, ca. 10 mm long; double coiled; ovary 2-locular, 6 ovules per locule. Fruits turbinate to cup-shaped, 3.5–5.7 (including operculum) × 3–6 cm. diam., 8–10 mm thick, the calyx-lobes persistent, woody, usually pointed (not rounded) at apex, the supracalycine zone 7–10 mm wide, convex, the infracalycine zone 18–39 mm wide, tapered to base, lenticellate, the operculum 1–1.3 × 3–3.5 cm diam., slightly umbonate, sometimes convex. Seeds 2–4 per fruit, globose, plane on 1–2 sides, hemispherical on other sides, 2 × 1.4 cm, the aril lateral, splitting at chalazal end into 2–3 branches, white.

Common names: Not known.

Distribution: This species has only been collected from the Caribbean slopes of Donoso district, Province of Colón, Panama.

Ecology: Understory to subcanopy trees of lowland mature and late secondary rainforest at 100– 350 meters above sea level. It is an abundant tree in the MPSA concession and adjacent areas.

Phenology: Flowers collected from February to September and sometimes in December. Fruits collected in February, May to July, September, and December.

Pollination: No published reports but species of Eschweilera are generally pollinated by bees attracted to the nectar produced in a chamber at the apex of the androecial coils.

Dispersal: No published reports but the seeds have a white, fleshy, lateral aril that is eaten by animals who most likely disperse the seeds.

Predation: No published reports.

Conservation Status: Eschweilera donosoensis has been collected only in the following locations: Botija; Valle Grande and other sites in The Minera Panama Mining concession; and a single collection (Holdridge 6249) outside of the copper mine concession in the Donoso District. Based on IUCN (2001) criteria this species is considered Endangered (EN) with an EOO of 369 square kms and an AOO of 40 square kms, [EN B1ab (i,ii,iii,iv,v)+2ab(i,ii,iii,iv,v)]. The mining activity and indigenous settlements have been fragmented into large-scale forest patches that are currently not protected by country or state governments.

Uses: No documented uses.

Etymology: The specific epithet of E. donosoensis is derived from the type locality in the Donoso District of Panama where it is common.

Field characters: This species is an endemic commonly found in the lowland rainforests of the Caribbean slopes in the Province of Colón. It is morphologically similar to Eschweilera hondurensis which has larger leaves 12-21 × 4-7 cm vs. 3.2-19.7 × 1.5-8.4 cm; a pedicel/hypanthium of 10-15 mm long vs. 6-7 mm long; calyx-lobes imbricate at base, not carinate vs. not imbricate or scarcely imbricate at base, carinate; fruits cup-shaped to depressed globose and pericarp thin-walled (1-2 mm thick) vs. turbinate-shaped and pericarp thick-walled (8-10 mm thick); seeds with a lateral aril not splitting at chalazal end vs. aril splitting at chalazal end into 2-3 branches. Eschweilera donosoensis can be confused with Eschweilera pittieri which has strongly imbricate calyx-lobes in flower that become large, woody and rounded at the apex in fruit whereas E. donsoensis has weakly imbricate calyx-lobes in flower that become woody and pointed at the apex in fruit. Another way to tell these two species apart is that the hypanthium of E. pittieri has a pustulate surface whereas it is smooth in E. donosoensis.

Taxonomic notes: Eschweilera donosoensis belongs to the E. parvifolia clade which differs from the E. integrifolia clade by having a double-coiled instead of triple-coiled androecial hood and a simple instead of a spreading aril (Huang et al., 2015). In addition, the petals and androecial hoods of species in the E. parvifolia clade most often have white petals and yellow androecial hoods instead of pink to dark pink petals and androecial hoods in species of the E. integrifolia clade. Species of the E. parvifolia clade are common in the lowlands throughout the range of the genus whereas only two species of the E. integrifolia clade are found in Amazonia (Mori et al., 2017). However, be aware that a few species of the E. integrifolia clade have white petals and yellow androecial hoods but also have triple-coiled androecial hoods and spreading arils.

Source: Based on J. E. Batista and S. A. Mori (2017).

Map Distribution

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Objects

Images

Flower of Eschweilera donosoensis. Image by J. Batista. (image/jpeg)

Medial longitudinal section of an androecium of Eschweilera donosoensis. Image by J. Batista. (image/jpeg)