Ormosia neillii J. L. Clark & J. E. Guevara 2025, sp. nov.
Creators: name: Guevara-Andino, Juan Ernesto
name: Clark, John L.
name: Navas-Muñoz, Daniel
Publisher: name: Zenodo
Year: 2025
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Magnoliopsida
Fabales
Fabaceae
Ormosia
Ormosia neillii

description: Ormosia neillii J. L. Clark & J. E. Guevara sp. nov.
Figs 1, 2, 3, 4
Diagnosis.
Ormosia neillii is morphologically similar to O. cuatrecasasii, but it can be differentiated by suborbicular to ovate glabrescent fruit with strongly cuspidate apex, smaller leaves (5–14.5 cm long vs. 10–30 cm long), smaller fruits (3.5–6 cm long vs. 5–10 cm long), larger calyx tube (10–15 mm long vs. 6–7 mm long) and uniformly light red to dark red seeds vs. bicolored seeds.
Type.
Ecuador • Zamora Chinchipe: Cantón Nangaritza, Parroquia Zumi, Cordillera del Cóndor, western side of tepui (bloque # 2) that overlooks Rio Nangaritza, directly east of Cabañas Yankuam, north of Reserva Natural Maycú and located in Área de Conservación Atasmo, 0.25 - hectare plot with the Lawrenceville School field course, 8 Mar 2018 (fl, fr), 04°15'13.8"S, 78°38'11.6"W, John L. Clark & David A. Neill 15775 (holotype: SEL; isotypes: ECUAMZ, MO, NY, US).
Description.
Tree 5–10 (15) m tall; trunk with outer bark brown-reddish covered by dark purple lenticels, inner bark reddish with longitudinal white stripes, young branchlets striate, petiole, leaf rachis and pulvinules densely tomentose, with flexuous, appressed, golden and ferruginous hairs or, rarely, glabrescent when in fruit. Stipules absent. Leaves (9.9 –) 11–26.5 cm long, imparipinnate, 3–7 - foliolate; pulvinus 6.4–7 × 2–5 mm, terete; petiole (1.7 –) 2–4.5 cm long; rachis (2.5 –) 5.5–16.5 cm long, interfoliolar segments 1–4 cm long; stipels absent; leaflets opposite, the pulvinules 4.3–4.5 × 1–2 mm, terete, the blades (5 –) 8–14.5 × (2 –) 3.5–7 cm, chartaceous, oblong-elliptic to broadly elliptic, basally truncate, apically acute and the margin slightly revolute, pubescent on the abaxial surface, the indumentum of adpressed yellowish hairs, the mid-vein abaxially prominent, the secondary veins in 10–12 pairs, eucamptodromous, well-raised abaxially, mostly 8–10 mm apart, arcuate, forming angles of 60 ° – 75 ° with the mid-vein, the tertiary veins reticulate, but inconspicuous. Panicle 12–15 cm long, terminal compact, composed by 3–10 racemes of 3–6.5 cm long; axes, bracts, bracteoles and pedicels densely tomentose, covered by erect, flexuous, yellowish hairs; bracts absent, pedicel 1.2–1.5 mm long, bearing one minute bracteole, attached at the base of the calyx, this ca. 1.5 mm long; flower buds 1–1.5 × 0.5–1 mm, oval-elliptic. Flowers 1.5–2.5 cm long, papilionate; calyx 8.5–12.3 × 5.8–9.2 mm, densely ferruginous tomentose externally, internally green, the tube ca. 8.5–10 mm long, the lobes 5–7 × 3–4 mm, triangular, the adaxial pair partially joined; petals dark purple to black, free, glabrous, clawed at the base, the standard 9–16 × 6–9 mm, white stripes at the base, orbicular, deeply incised, basally rounded, apically emarginate, the wings 6.5–15 × 3.5–4.5 mm, oblong-lunate, the keel petals 6.5–15 × 2.5–3 mm, oblong-lunate, basally auriculate; stamens 10, in different sizes, the largest ca. 2 times larger than the smallest, the filaments of the smallest 4–6 mm long, the largest ones 12–14 mm long, free, glabrous, basally dilated, apically curved, anthers of the smallest stamens 1.0–1.5 × 0.2–0.4 mm, anthers of the largest ones 1.5–2.0 × 0.2–0.4 mm, basifixed, elliptic to oblong in outline; intrastaminal disc ring-shaped, glabrous, compressed; gynoecium 6–8 mm long, the ovary 5–6 × 1.2–2.0 mm, oblong in outline, laterally compressed, uniformly densely pilose, ovary subtended on a stipe 1–2 mm long, 3 - ovulate, the style ca. 7 mm long, glabrous, apically curved, the stigma laterally bilobed. Fruit 2.5–7.5 × 1.4–2.5 cm, dehiscent along both sutures, suborbicular to ovate when one-seeded, oblong-elliptical when more than 2 seeds present, apically cuspidate, glabrous at maturity, the valves coriaceous to woody, 0.5–1.5 mm thick. Seeds 1–5, 9–11 × 8–10 mm, unicoloured, light to dark red, oval to suborbicular in outline, slightly compressed; hilum 2.3–2.8 × 1.3–1.6 mm, elliptic.
Additional specimens examined.
Ecuador: Morona Santiago • Limón Indanza, Cordillera del Cóndor, Centro Shuar Yunkuam, Cerro Chuank Naint (Vulture Mountain in Shuar language), collections made near a 1 - hectare forest inventory plot, 17 Sep 2005, 1150 m a. s. l., 03°3'34"S, 78°14'45"W, D. A. Neill & NSF dendrology course 14614 (MO, QCNE!). Zamora Chinchipe • cantón Nangaritza, Cordillera del Cóndor, tepui near Mirador del Nangaritza, directly northwest of ATASMO (Asociación de Trabajadores Autónomos San Miguel de las Orquídeas), drainage that includes río Chamico, 0.25 hectare tree inventory plot, “ Rio Chamico ” with the Lawrenceville School field course, 7 Mar 2017, 1353 m a. s. l., 04°12'31"S, 78°40'55"W, J. L. Clark, J. A. Mayr & D. A. Neill 15159 (ECUAMZ); • same locality, 8 Mar 2017, J. L. Clark, J. A. Mayr & D. A. Neill 15217 (ECUAMZ, G, MO, NY, SEL, US); cantón Nangaritza, parroquia Zumi, Cordillera del Cóndor, western side of tepui (bloque 2) that overlooks Río Nangaritza, directly east of Cabañas Yankuam, north of Reserva Natural Maycú and located in Área de Conservación ATASMO (Asociación de Trabajadores Autónomos San Miguel de las Orquídeas), 0–25 - hectare plot with the Lawrenceville School field course, 1400 m a. s. l., 7 Mar 2018, 04°15'13.8"S, 78°38'11.6"W, J. L. Clark & D. A. Neill 15612 (ECUAMZ, SEL); same locality, 7 Mar 2018, J. L. Clark & D. A. Neill 15633 (ECUAMZ, MO, SEL, US); same locality, 7 Mar 2018, J. L. Clark & D. A. Neill 15638 (ECUAMZ, F, G, MO, NY, SEL, US); same locality, 7 March 2018, J. L. Clark & D. A. Neill 15649 (BM, CAS, ECUAMZ!, E, F, FLAS, G, MO, NY, SEL, US); • same locality, 7 March 2018, J. L. Clark & D. A. Neill 15667 (ECUAMZ, MO, SEL, US); • same locality, 7 March 2018, J. L. Clark & D. A. Neill 15677 (ECUAMZ, MO, SEL, US); • same locality, 7 March 2018, J. L. Clark & D. A. Neill 15693 (ECUAMZ, F, G, SEL); • same locality, 7 March 2018, J. L. Clark & D. A. Neill 15697 (ECUAMZ, MO, SEL); • same locality, 7 March 2018, J. L. Clark & D. A. Neill 15715 (ECUAMZ, MO, SEL); • same locality, 8 March 2018, 04°15'13.8"S, 78°38'11.6"W, J. L. Clark & D. A. Neill 15736 (ECUAMZ!, MO, SEL); • same locality, 8 March 2018, 04°15'13.8"S, 78°38'11.6"W, J. L. Clark & D. A. Neill 15756 (ECUAMZ!, MO, SEL); • same locality, 8 March 2018, J. L. Clark & D. A. Neill 15767 (ECUAMZ!, SEL!, US); • Cantón Nangaritza, Parroquia Zurmi, Cordillera del Cóndor, sloping sandstone tepui, east of Río Nangartiza, 2 km southeast of Las Orquídeas Village, in Área de Conservación de Las Orquídeas, 0.25 - hectare forest inventory plot, “ Parcela Atasmo Norte ” with the Lawreenceville School field course, 7 Mar 2019, 1515 m, 4°14'14"S, 78°38'33"W. J. L. Clark, D. A. Neill, E. Merino & A. Wilcox 16085 (ECUAMZ, LOJA, SEL); same locality, 7 Mar 2019, J. L. Clark, D. A. Neill, E. Merino & A. Wilcox 16085 (ECUAMZ, SEL); • Cordillera del Cóndor Región, upper Río Nangaritza, “ Area de Conservación los Tepuyes ”, on upper portion of sloping sandstone plateau southwest of Las Orquídeas, near 1 - hectare forest inventory plot “ Nangaritza Upper Sandstone Plateau Plot ”, 1620 m a. s. l., 6 Nov 2006, 04°15'13.8"S, 78°38'11.6"W, D. A. Neill & NSF dendrology course 15465 (MO, QCNE, ECUAMZ); • Cordillera del Cóndor, Upper Nangaritza River, Comunidad Las Orquídeas, tepui east to Cabañas Yankuam in Reserva Natural Maycú, 1480 m a. s. l., 18 Oct 2024, 04°15'29.56"S, 78°38'19.59"W, J. E Guevara, M. J. Endara & W. Raura 6790 (F, QCA, QCNE); • same locality, 18 Oct 2024, 04°15'29.56"S, 78°38'19.59"W. J. E Guevara, M. J. Endara & W. Raura 6789 (F, QCA, QCNE).
Distribution and habitat.
Ormosia neillii is a medium-sized tree to 15 m tall and only known from two localities on sandstone plateaus of the Cordillera del Cóndor (Clark and Neill 2023) (Figs 2, 5). It is locally abundant on white sand dwarf forests on Andean tepui-like formations above 1000 m altitude (Figs 2 A, B, 5 B). The maximum height observed in the field was 15 m and when cut, the inner bark is remarkably reddish (Fig. 2 C, D). Some conspicuous floristic elements of this habitat include Sterigmapetalum obovatum Kuhlm. (Rhizophoraceae), Humiriastrum mapiriensis Cuatrec. (Humiriaceae), Andira sp. nov. (Fabaceae), Sloanea tiwintza T. D. Penn. (Elaeocarpaceae), Wettinia longipetala A. Gentry (Araceae), Psamnisia sp. (Ericaceae), Cybianthus magnus (Mez) Pipoly (Primulaceae) and Ladenbergia franciscana C. M. Taylor (Rubiaceae). This area forms part of a landscape of isolated, tepui-like plateaus dating back to the Cretaceous period, characterised by low-stature forests rich in small trees with slender stems (Guevara and Fernández-Alonso 2018; Huamantupa-Chuquimaco and Neill 2018; Clark and Neill 2023). The upper soil layer consists of 20–50 cm of litter, beneath which soils rich in quartzitic white sands predominate. These types of environments in the Cordillera del Cóndor and other mountain ranges to the east of the Andean Mountain range in Ecuador and Peru are commonly referred to as “ Andean tepuis ” (Neill et al. 2014; Clark and Neill 2023). Ormosia neillii is endemic to Ecuador, but it is also expected to occur in similar sandstone habitats of unexplored regions of the Cordillera del Cóndor in Peru.
Etymology.
The specific epithet honours the botanical legacy of Dr David A. Neill (1953–2025), an American botanist who dedicated over three decades to the study of Ecuadorian flora. Dr Neill conducted extensive botanical surveys throughout Ecuador and played a pivotal role in mentoring numerous generations of botanists through his teaching, research and service. A passionate advocate for both botanical science and habitat conservation, he was instrumental in the establishment of several biological research stations in collaboration with the Jatun Sacha Foundation, a non-profit NGO he helped establish in the 1980 s. His taxonomic expertise, particularly within the Fabaceae family, is widely acknowledged. This epithet serves as a fitting tribute to his legacy in plant systematics, Fabaceae taxonomy and his invaluable contributions to the field of botany.
Conservation status.
The range size analysis estimated an EOO of 748.8 km 2 and an AOO of 24 km 2. Our analysis also revealed that, since 2000, this species has suffered a significant reduction in its habitat quality considering a reduction of 7 % for AOO and 11 % for EOO. Ormosia neillii is only known from three localities in the Upper Nangaritza River and one locality in Cerro Plateado, all in the Cordillera del Cóndor Region (Fig. 6). Extensive clear-cutting during the last ten years has resulted in a drastic reduction of native forests (Tapia-Armijos et al. 2015). The expansion of both legal and illegal mining are additional major threats in the region (CEECEC [Civil Society Engagement with ECological EConomics] 2024). Ormosia neillii is preliminarily assessed as Endangered (EN), based on the following IUCN (2022) criteria: B 1, B 2 ab (i, ii, iii) where EOO is less than 5,000 km 2 and subcriteria indicate continuing decline, observed, inferred or projected, in area, extent and / or quality of habitat.
description: Published as part of Guevara-Andino, Juan Ernesto, Clark, John L. & Navas-Muñoz, Daniel, 2025, Ormosia neillii (Fabaceae), a remarkable new tree species from the Cordillera del Cóndor plateaus in Ecuador, pp. 21-35 in PhytoKeys 256 on pages 21-35, DOI: 10.3897/phytokeys.256.147923