Lepanthes cerambyx is a small, tufted epiphytic orchid with slender roots and erect, slender secondary stems (ramicauls) 3–10 cm long, enclosed by six to ten close, glabrous lepanthiform sheaths — the funnel-shaped, fringed sheaths characteristic of the genus. Each ramicaul bears a single erect, leathery, narrowly ovate leaf, acute and shortly acuminate at the apex, 3–5 cm long and 0.5–0.9 cm wide, the base cuneate to an indistinct petiole 1 mm long or with no petiole.

The inflorescence is a very congested, successively flowered raceme up to 10 mm long, borne on top of the leaf by a filiform peduncle 4–10 mm long — unusually short among Lepanthes species, with the result that the flower sits directly on the dorsal (upper) surface of the leaf rather than hanging from it. The floral bracts are imbricating, 1.5 mm long; the pedicel 2–3 mm; the ovary 1.5 mm. The sepals are yellow, lightly veined with purple, ovate and obtuse: the dorsal sepal is 3.5 mm long and 2.8 mm wide, connate to the lateral sepals for 0.5 mm; the lateral sepals are oblique, 3.25 mm long and 2 mm wide, connate 0.75 mm. The petals are glabrous, orange, suffused with red medially, transversely bilobed, 1 mm long and 3.75 mm wide; the upper lobe is erect in the natural position, oblong, obliquely truncate with the angles lightly acuminate and rounded — the character that produces the flower's resemblance to the horns of a beetle; the lower lobe is narrowly oblong and obtuse. The lip is bilaminate and at most microscopically pubescent, the blades purple, elliptical with rounded ends, 1.2 mm long; the connectives cuneate from the anterior half of the blades; the body broad, connate to the column at the base, the sinus protruding with a small but broad, pubescent appendix with a bilobed apical segment. The column is comparatively large and thick, 2 mm long, with a dorsal anther and a ventral stigma.

Flower characteristics at a glance: the flower is small (sepals 3–3.5 mm long) but bright, with yellow sepals lightly veined in purple, an orange lower face produced by the two-lobed petals, and a prominent magenta lip projecting forward. The erect, truncate upper lobes of the petals — the "beetle horns" — give the species its name. The short peduncle places the open flower flush with the leaf surface, with additional buds along the same short raceme, so that an observer looking down at a flowering plant sees flower and leaf together in a single plane.

The morphological characters described here follow Luer & Escobar (1991); the description is reproduced with minor modernization by Luer & Thoerle (2012) in Icones Pleurothallidinarum XXXII.

The published literature describes Lepanthes cerambyx as an epiphyte of Andean cloud forests, with the type locality in Cocorná (Antioquia) at approximately 1,600 m (Luer & Escobar, 1991). IOSPE reports the species as a cool-growing epiphyte from 1,600 to 2,000 m (Pfahl, n.d.).

In La Honda, the species has been observed under substantially different ecological conditions from those reported in the literature. Plants were found growing rupicolously — on moss-covered rocks beside a shaded stream, positioned above the flow line but within the zone kept humid by spray and splash. The plants form patches clustered at specific microsites along the creekbank where conditions (humidity, moss cover, rock orientation, shade) are suitable; the species has not been observed elsewhere in the vereda despite apparently suitable forest habitat nearby. This suggests that suitable microhabitat, rather than forest availability per se, is the limiting factor locally.

No plants have been observed in La Honda growing on woody vegetation in the manner described by the protologue. Whether the La Honda population represents a previously-undocumented facultatively rupicolous habit of this species, a response to specific local conditions, or some other pattern cannot be determined from a single observed site and will benefit from further observation and comparative study.

Lepanthes cerambyx is endemic to Colombia, known from the department of Antioquia (POWO, 2026). The holotype was collected in the municipality of Cocorná, along the Autopista Medellín–Bogotá by the Río Cocorná, at 1,600 m (21 August 1984; R. Escobar, C. Head & E. Valencia 3382, JAUM; isotypes at COL and MO; illustrated as C. Luer 10467) and published by Luer & Escobar (1991).

The La Honda record documents a newly-confirmed locality approximately 15 km northeast of the type locality, in an adjacent municipality within the same eastern-Antioquia cordillera corridor. Because the La Honda plants have been observed in a substantially different microhabitat (rupicolous, streamside) from those documented in the published literature (epiphytic, forest), the ecological significance of this range extension merits further observation and independent verification.

Flowering has been observed in La Honda, with multiple plants in patches carrying open flowers and buds simultaneously. Because the species is known from a single microhabitat locally and has been observed on a limited number of occasions, seasonality at this site cannot be reliably characterised from the available data. Systematic observation across a full annual cycle would be required to describe the phenology of the local population.

Recognition rests on the combination of the narrowly ovate leaf, the very short peduncle that places the flower directly on the dorsal surface of the leaf rather than hanging from it, the small yellow-sepalled flower with a prominent magenta lip, and above all the erect, truncate upper lobes of the petals — the "beetle horns" from which the species takes its name. The genus Lepanthes is diagnosed as a whole by the lepanthiform sheaths on the ramicauls, visible with a hand lens.

Lepanthes cerambyx has not been evaluated globally on the IUCN Red List (status NE, Not Evaluated, as of the date of this sheet). At the national regulatory level in Colombia, the species is not listed in Resolución 0126 de 2024 of the Ministry of Environment; it is therefore not classified as threatened under current Colombian environmental law.

"Not Evaluated" is not a statement that the species is safe — it is a statement that no formal assessment has been made. Miniature orchids of the genus Lepanthes, including species not yet formally assessed, remain subject to poaching for specialist collectors, and populations can be depleted by collection far faster than an assessment system can respond. The La Honda population merits particular attention on two grounds: its narrow microhabitat dependency (rocks beside a specific creekbank, kept humid by stream spray) makes the local population vulnerable to changes in the watercourse — whether through land-use change, water abstraction, or reduced dry-season flow — and the patchy distribution means any single disturbance event could affect a disproportionate fraction of the local population.

For these reasons, the specific location within La Honda where L. cerambyx has been documented is not published, and elevation data are redacted from this sheet. Requests for further locality detail from researchers or conservation practitioners with a legitimate scientific or institutional purpose may be directed to [email protected].