Epidendrum rasmussenii Gómez-Riaño, C.Castro & E.Santiago, 2025

Epidendrum rasmussenii Gómez-Riaño, C.Castro & E.Santiago , sp. nov.

( Figures 2–3 View FIGURE 2 View FIGURE 3 )

Type: — COLOMBIA. Magdalena: Sierra Nevada de Santa Marta , Municipio de Santa Marta, corregimiento de Minca , vereda San Lorenzo, sendero cerro Kennedy , 2540 m, 24 April 2023, Miguel Ángel Gómez-Riaño 233 (holotype: COL 6308269 !).

Similar to Epidendrum stenostachyum Hágsater & Santiago (2004: 791) but differing by the red-carmin to yellow-green flowers with yellowish green towards apex in sepals and petals (vs. yellow-green, spotted with purple flowers), petals 5.6 × 0.4 mm, parallel to column and linear-filiform (vs. petals 6.8 × 1.3 mm, falcate, reflexed and linear-oblanceolate) and the lip reniform-cucullate and embracing apex column in natural position. (vs. lip widely triangular-ovate, flat).

Description:— Epiphytic, monopodial, branching, erect herb, 15–33 cm tall. Roots ca. 3 mm in diameter, basal, fleshy, white velamen, purple cortex. Stems branching, primary stem ca. 18.7 × 0.3 cm, branches 5.5–16.4 × 0.2–0.3 cm, canelike, terete at base to slightly laterally compressed towards apex, gradually smaller, produced from a subapical internode of previous branch; all covered with non-foliar sheaths 0.6–2.5 × 0.2–0.4 cm, tubular, minutely striated. Leaves in main stem not seen, ca. 8, green, concolor distributed from middle of stems, aggregate towards apex, coriaceous, suberect, articulate, alternate; sheaths 4–18 mm long, green when young turning reddish when mature, tubular at base, infundibuliform apex, minutely striated; blade 3.7–6.6 × 0.4–0.7 cm, lanceolate, apex obtuse, margin minutely dentate, spreading. Spathe lacking. Inflorescence 3.1–5.5 cm long, apical, racemose, arching-nutant, compact, many flowered; peduncle 6.5–7 mm long, green concolor, laterally compressed, with two basal bracts ca. 5.5mm long, triangular-lanceolate; rachis 2.5–4.5 cm long, green, hidden entirely by flowers. Floral bracts ca. 4.1 × 6 mm, green or green reddish tinged, shorter than ovary, triangular, acute, embracing the ovary. Pedicellate Ovary ca. 3.2 mm long, green reddish tinged unornamented, terete. Flowers 22–40, resupinate, some fleshy, red-carmin, yellowish green towards apex in sepals and petals, lip basally with light yellowish tones, no fragance. Sepals 5-veined, apex obtuse, minutely apiculate, margin entire, spreading; dorsal sepal 5.9–6.0 × ca. 2 mm, free, spreading, oblanceolate; laterals sepals 7 –8.4 × 2.5–3.0 mm, obliquely united to column, parallel to column, narrowly obovate, oblique. Petals ca. 5.6 × 0.4 mm, free, parallel to column, linear-filiform, 1-veined, margin entire, spreading. Lip ca. 4.5 × 7.5 mm, united to column, concave, cucullate in natural position, embracing apex column in natural position; reniform, base cordate, apex widely emarginate, margin entire; bicallose, calli, short, fleshy, flattened, separated; disc with a wide, fleshy, low keel, that runs to apex of lip. Column 4.4–5 mm long, yellowish green turning red-carmin in apex, thin at base and gradually wider at apex, straight, apex with pair of widely triangular wings, Clinandrium-hood short, margin entire. Rostellum apical, split; viscarium semi-liquid, transparent. Lateral lobes of stigma not seen. Cuniculus short, without surpassing perianth, wide, not inflated, unornamented. Anther yellowish green, sub-reniform, apex emarginated, 4- celled. Pollinia 4, obovoid. Capsule ca. 29 × 7 mm, green, ellipsoid.

Distribution and Ecology: — Epidendrum rasmussenii is currently known only from Sierra Nevada de Santa Marta in the department of Magdalena, at elevations of 2500 to 2800 meters, where occurs as epiphytic on mediumsized trees in cloud forests. The flowering period in the field is in April and May.

Etymology: —In honor of the memory of Nathan Jens Rasmussen (2001–2022), a beloved son deeply committed to nature conservation. He and his family provided crucial support to the El Dorado reserve, located in the Sierra Nevada de Santa Marta, the type locality of this new species for science. Thanks to the Rasmussen family’s support, the reserve preserves a significant portion of the valuable and unique biodiversity of cloud forests in these ancestral lands.

Conservation status: —The species was first collected in April 1959 in the Cuchilla de San Lorenzo. It was collected again in April and May 2022 at the same location. Two years later, in May 2024, additional records were obtained from populations slightly farther from the original site. Cuchilla de San Lorenzo is characterized by a cloud forest between 2,500 and 2,800 meters above sea level, within a continuous forest patch that is disturbed at higher elevations but much more conserved at lower elevations. For the past 20 years, the area has been declared a protection and conservation area by ProAves Foundation, bordering the Sierra Nevada de Santa Marta National Natural Park. Human activity is restricted in these areas by the Colombian National Parks system and the ProAves Foundation, although the surroundings have been highly disturbed in the past.

A recent visit to this area revealed that more individuals of the species are currently present, often very close to or on the same trees where the herbarium specimens were collected, where it can be the most dominant epiphyte. Based on this information, the species likely has a very restricted distribution to the Sierra Nevada de Santa Marta, with an estimated extent of occurrence (EOO) of 15 km ² and an area of occupancy (AOO) of 32 km ², known from only one locality. Despite nearby threats to habitat quality due to the expansion of agricultural activities, the species is currently protected and seems likely to remain so in the near future. Considering this information, the combination of an EOO of less than 5,000 km 2, an AOO between 10 and 500 km 2, and the presence of the species in only one severely fragmented location, we propose that the species should be categorized as Endangered (EN B1ab[iv]+B2ab[iv]) ( IUCN 2024).

Additional specimens examined: — COLOMBIA. Magdalena: Cerro Kennedy, Castro 3391 ( COL!) ; Ibid. 2500–2600 m, 02 May 2023, Gómez-Riaño 307, ( COL!); Cerro Kennedy, 2500–2600 m, 23 May 2023, Gómez-Riaño 311, ( COL!), Ibid. Gómez-Riaño 312, ( COL!), Cerro Quemado y Cerro San Lorenzo, 2600–2800 m, 16 April 1959, Romero-Castañeda 7754, ( COL!), Cerro Quemado y Cerro San Lorenzo , 2600–2800 m, 17 April 1959, Romero-Castañeda 7767, ( COL!), Ibid. Romero-Castañeda 7771 ( COL!), Cerro Quemado y Cerro San Lorenzo, 2600–2800 m, 22 April 1959, Romero-Castañeda 7843 ( COL!).

Taxonomic discussion: — Epidendrum rasmussenii is distinguished by its monopodial, branching growth habit; leaves 3.7–6.6 × 0.4–0.7 cm, lanceolate; inflorescence 3.1–5.5 cm long, arching-nutant, and bearing light yellow-green to deep red-carmine flowers; lip 5 × 7 mm, reniform, cucullate, and concave in its natural position, with two flattened and separated calli; petals 5.6 × 0.4 mm, linear-filiform, and parallel to the column. It is vegetatively similar to E. stenostachyum but the latter has a spreading lip, flat, widely triangular-ovate, apex slightly retuse; the petals 6.8 × 1.3 mm, falcate, reflexed and linear-oblanceolate ( Figure 4 View FIGURE 4 ). E. rasmussenii could also be confused with Epidendrum karstenii Reichenbach (1877: 37) but this species has a 3-lobed lip; the new stems are produced from an intermediate of the previous stem and the foliar sheath is not infundibuliform. Finally, the flowers of E. rasmussenii exhibit a color variation among its populations ranging from a light yellow-green to a deep red-carmin ( Figure 5 View FIGURE 5 ).

Several specimens previously identified in COL as Epidendrum stenostachyum , following flower rehydration and morphological comparisons, were found to align with the characteristics of E. rasmussenii . This means that the new species had been collected as early as 1959 by Romero-Castañeda in the same locality, but remained misidentified in herbaria for approximately 65 years.

Epidendrum rasmussenii is the fourth species of the Soratae subgroup found on the Sierra Nevada de Santa Marta, and is recorded only for the northwestern slope of the mountain massif. Its closest relative, E. stenostachyum , is similarly restricted to the headwaters of the Sevilla River on the SNSM’s western side, while Epidendrum purdii occurs further east, near the headwaters of the Palomino River. Other related species, such as Epidendrum sumapacense , are found in Cundinamarca, Meta, and Magdalena, whereas E. oscar-perezii is restricted to Boyacá. In contrast, the remaining species have broader distributions in the southern Neotropics.