Ceratostema gearyana M. M. Jiménez & H. Garzón, 2025

Ceratostema gearyana M. M. Jiménez & H. Garzón sp. nov.

Materials

Type status: Holotype. Occurrence: recordNumber: H. Garzón 295; recordedBy: H. Garzón; occurrenceID: 78A4C16D-A458-529E-AAF3-5B552693A512; Taxon: scientificName: Ceratostema gearyana M. M. Jiménez & H. Garzón ; Location: country: Ecuador; stateProvince: Morona Santiago; locality: Reserva Agett-Geary, cerca de San Juan Bosco ; verbatimElevation: 1663 m; Event: year: 2025; month: 5; day: 1; Record Level: institutionCode: HUTPL!

Description

Shrubs pendant, epiphytic; indumentum consisting of almost persistent trichomes, white, eglandular, 0.3–1.1 mm long, arranged unevenly, sparsely to densely on younger branches, petioles, leaf blades, inflorescences and flowers, excluding stamens; axonomorphous roots with a woody, subpsherical, well-developed lignotuber-like swelling. Stems terete to subterete, ca. up to 1.4 m long, glabrous, slightly arching, arising from the swelling, older stems dark brown, cracking longitudinally and exfoliating; younger branches terete, ca. 80 cm long, 2.1 mm wide, pendant, slightly arcuate, pale green, puberulous, becoming striate and dark brown when old or after exfoliation; axillary buds emerging 1 mm below the leaf node, axillary bracts 1.2–2.5 mm long, pale green, sparsely pubescent, ovate triangular. Leaves spirally arranged, pendulous; petioles pale green, subterete 3.8 mm × 2.1–2.3 mm, pubescent; blades dark green in older, paler in mature and mahogany in younger leaves, cordiform to ovate-orbicular, 10.3–12.8 cm × 6.6–8.6 cm, coriaceous, convex with basal margins folded to conceal flowers and fruits, glabrous adaxially, with very few sparse hairs at the basal margin abaxially, pruinose adaxially and abaxially, 7–9 - plinerved from near the base, sometimes with an inner pair of lateral nerves arising from the proximal 0.8–1.5 cm, midvein raised along almost its length adaxially, impressed and hollow abaxially, secondary veins slightly raised adaxially, impressed abaxially, branching, anastomosing distally with reticulate veinlets weakly raised to obscure, base cordate, margin undulate, apex shortly acuminate to acuminate. Inflorescence axillary, a cincinnus with very compact internodes, pendulous, sessile, 2–3 - flowered; rachis obconical, 3.7–4.4 mm long, 1.8 mm thick, puberulous, subverrucose, covered at the base by several bracts; bracts persistent, whitish-green, ovate, 0.9–1.1 mm × 1.2–1.6 mm, ciliate to the margin, acute to obtuse at the apex; floral bracts persistent, similar in colour and texture to the peduncle bracts, ovate, 0.8–1.1 × 0.8–1.2 mm, acute; pedicel articulate with the calyx, pale green, subterete, 7.6–8.4 mm long, 1.9–2.5 mm thick, puberulous; bracteoles persistent, 2, whitish-green, ovate-triangular, 0.6–0.8 mm × 0.7-0.8 mm, located near the base and opposite, long-ciliate along the margins, apex attenuate. Flowers pentamerous with pale green calyx and dark reddish-brown corolla, paler at the base; calyx 7.2–8.9 mm × 6.1–6.6 mm, puberulous; hypanthium obconical, obscurely pentagonal, 5.5–6.3 mm × 3.7–4.1 mm, truncate; limb erect, open, 3.2–3.6 mm × 6.1–6.6 mm; lobes 5, ovate-deltate, 2.0– 2.7 mm × 2.8–3.0 mm, slightly convex, apiculate at the apex, sinuses acute. Corolla tubular, but slightly dilated to the base and narrowing distally, thick-carnose, bistratose, 4.2–4.4 cm long (including the lobes), 6.5 mm in diameter at the base, 5.4 mm in diameter at the throat, puberulent and bluntly 5 - angled along its length externally, puberulous in the internal apical half; lobes 5, spreading, narrowly linear-triangular, 19.8–22.3 mm × 2.2–3.0 mm, lustrous, puberulent externally, glabrous internally, channelled and subverrucose internally, slightly incurved to the base, recurved and acuminate at the apex. Stamens 10, with white filaments, golden yellow tubules and darker thecae, nearly equalling the corolla in overall length, each pair unequal, 3.6–4.0 cm long; filaments connate forming a tubular staminal tube, 8.8–9.2 mm long, glabrous outside, visibly papillose inside; anthers 3.2–3.6 cm long, each pair of thecae unequal, prognathous, 6.2–6.6 mm long, conspicuously papillose; tubules distinct, slightly unequal, seemingly free, 2.7–3.0 cm long, glabrous, dehiscing by terminal pores, ca. 0.9 mm × 0.4 mm. Style green, exserted, 4.4 cm long, pilose, stigma truncated. Mature fruit yellowish-green, subglobose, ca. 14.0– 16.8 mm × 15.0 mm in diameter, puberulous, with persistent calyx lobes. Seed not seen (Fig. 1 View Figure 1 ).

Diagnosis

Ceratostema gearyana is distinguished from C. cutucuense by the smaller leaves, 10.3–12.8 cm × 6.6–8.6 cm (vs. 14.0–16.0 cm × 9.0–11.0 cm), the glabrous floral parts (vs. puberulous), the hypanthium smaller, obconic, obscurely pentagonal (vs. turbinate, bluntly 5 - winged), the larger calyx lobes deltate-ovate, 2.0– 2.7 mm long (vs. truncate, <0.5 mm long) and the corolla bluntly 5 - angled (vs. bluntly 5 - winged), with longer, narrowly linear-triangular lobes, 19.8–22.3 mm long (vs. linear-lanceolate, 12.0–14.0 mm long).

Etymology

This species is named after the Agett-Geary Reserve, a recently created private protected area, where the new species was discovered.

Distribution

Ceratostema gearyana is known from a single population near San Juan Bosco in the south-eastern Ecuadorian Province of Morona-Santiago (Fig. 2 View Figure 2 ).

Ecology

The new species grows as a pendant epiphytic species at elevations between 1400 to 1600 m (Fig. 3 View Figure 3 ). This area is characterised by mature and disturbed primary forests where C. gearyana co-exists with other flora, including: Blakea hirsutissima (J. F. Macbr.) Wurdack , Ceratostema glans Luteyn , Elleanthus blatteus Garay , Sphyrospermum glutinosum Luteyn & Pedraza and S. kakabadseae A. Doucette, H. Medina & J. Portilla.

Conservation

Ceratostema gearyana has been located within the buffer zone of the Siete Iglesias Municipal Conservation Area (ACMSI), but not inside the Reserve. Seven individuals are known from the type locality. The main threat to the conservation of this population remains the destruction of primary forests for timber, pasture and cattle grazing. Regardless, its proximity to the aforementioned municipal reserve, which is dedicated to the conservation of primary forest, led the authors to believe that C. gearyana is well represented within its boundaries and therefore protected.

Applying conservation analysis with the georeferenced single locality, the calculated area of occupancy (AOO) is 4 km 2. The extent of occurrence (EOO) has not been calculated due to the limited number of populations sighted. For these reasons, the authors recommend C. gearyana should be considered Critically Endangered (CR) according to the IUCN Criteria B 2 ab (i, ii), C 2 a (i) and D 1 ( IUCN 2024).

Taxon discussion

Ceratostema gearyana is the newest addition to the informal " auriculatum group ". Coherent traits for this group are: the epiphytic, long-pendant habit; the twigs are embraced by amplexicaul, cordate and convex, folded downwards at the base and hiding the few flowered inflorescences; the sessile, axillary inflorescences; the minute floral bracts and bracteoles; and the calyx with a 5 - winged hypanthium and a non-prominent limb.

Ceratostema gearyana is most similar to C. cutucuense by the glaucous younger branches; the glabrous, suborbicular leaves; the erect calyx limb with the apiculate lobes; the acute sinuses; and the stamens having glabrous filaments. Nevertheless, C. gearyana is distinguished from C. cutucuense by the characters stated in the diagnosis. Further differences with the other species, additionally are the leaves that have basal lobes parallel to each other (vs. imbricate), the foliar apices being acuminate (vs. abruptly cuspidate to shortly acute), the 2–3 - flowered inflorescences (vs. 4–5 - flowered), the smaller pedicel, 7.6–8.4 mm long (vs. 12.0–13.0 mm long), the apically acuminate corolla lobes (vs. spurred), the stamens being comparatively shorter (3.6–4.0 cm long vs. ca. 5.0 cm long) and the filaments being comparatively longer (8.8–9.2 mm long vs. 6.0 mm long) ( Luteyn 1996). The new species is further distinct within the “ auriculatum group ” by its notably pruinose leaves, where the basal margin becomes pubescent when mature and later glabrous at a post-mature stage.