Pleurothallis pridgeoniana Karremans, Bogarín & Pupulin, 2025

Karremans, Adam P., Pupulin, Franco, Gange, John & Bogarín, Diego, 2025, Three new species of Pleurothallis (Orchidaceae) from Costa Rica and Panama, with a note on asexual reproduction by prolification in Pleurothallidinae, PhytoKeys 256, pp. 197-220 : 197-220

Pleurothallis pridgeoniana Karremans, Bogarín & Pupulin sp. nov.

Type.

Costa Rica. Puntarenas: Buenos Aires, Buenos Aires, camino a Cerros Utyum , 9°18'04.93"N, 83°12'51.59"W, 2157 m, bosque pluvial montano bajo, epífitas en bosque secundario, 16 January 2017, fl. in cult. 20 December 2017, A. P. Karremans, D. Bogarín, M. Cedeño, I. Chinchilla, M. Díaz, E. Kaes, P. Lehmann & O. Zúñiga 7600 (holotype: JBL - spirit, E 1514 !; isotype, USJ!; Fig. 5 ) .

Diagnosis.

Vegetatively similar to P. vinealis , but distinguished by the significantly shorter plants, up to 30 cm long (vs. exceeding 1 m), the shorter ramicauls 7.5–26.0 cm (vs. up to 40 cm long), the significantly smaller dorsal sepal (6.8–7.0 × 3.3–3.4 mm vs. 11–14 × 4.5–5.5 mm), synsepal (5.5–6.5 × 4.1–4.2 mm vs. 11–14 × 4.5–5.5 mm), and lip (2.4–2.6 × 1.6–1.7 mm vs. 5.5–6.5 × 3 mm). The flowers are transparent yellow, with a rose to purple suffusion (vs. brown), the lip is triangular-ovate (vs. oblong) the margins being shortly glandular (vs. denticulate), slightly raised but lacking a central sulcus (vs. prominently sulcate).

Description.

Epiphytic, caespitose, strictly prolific, erect to suberect herb, up to 30 cm long. Roots flexuous, thin, ca. 1 mm in diameter, densely spaced, appearing fasciculate. Primary ramicauls erect to suberect, slender, 7.5–26.0 cm long, with 2 basal tubular, tightly adpressed, papyraceous sheaths, up to 2.0–6.0 cm long. Secondary ramicauls 1.5–8.0 cm long, produced profusely from the floral meristem on the apex of prior ramicauls, being able to produce clumps and chains of multiple ramicauls before severing naturally. Leaves spreading to pendent, coriaceous, sessile, narrowly ovate to cordate, acute, blades of primary ramicauls 4.0–7.7 × 1.8–5.0 cm, blades on secondary ramicauls 2.5–5.2 × 1.0– 2.5 cm. Inflorescence persistent, forming successive multi-flowered coflorescences with a single open flower, subtended by a nearly prostrate or suberect spathe which appears deeply torn over time, ca. 1 cm long; pedicels cylindrical. Ovary slightly clavate, ca. 3 mm long, green, with a few black dots and occasional crystals. Flowers spreading, transparent yellow, with a rose to purple suffusion of varying intensity, especially observed on the petals, lip, column, and anther cap. Dorsal sepal narrowly ovate to elliptic, acute, 3 - veined, 6.8–7.0 × 3.3–3.4 mm. Lateral sepals connate in an ovate synsepal, acute, 4 - veined, 5.5–6.5 × 4.1–4.2 mm. Petals naturally drooping, linear-lanceolate, oblique, acute, 1 - veined, 5.1–5.4 × 0.6–0.7 mm, glandular, with the margins erose. Lip triangular-ovate, resting on the synsepal, 2.4–2.6 × 1.6–1.7 mm, blade glandular-papillose, margins minutely glandular, slightly raised, acute, shortly apiculate, with a pair of shoulder-like basal lobes. Glenion a shallow, oblong cavity between raised lateral margins. Column straight, transversely suboblong, ca. 1.5 mm long, with a short column foot, the anther and stigma apical. Anther cap ovate, cucullate, obtuse, 2 - celled. Pollinarium composed of 2 narrowly ovate-pyriform pollinia connected to a liquid, drop-like viscidium. Fruits and seeds unknown. This description is based on A. P. Karremans et al. 7600, A. P. Karremans et al. 9135, D. Bogarín et al. 8632, D. Bogarín et al. 12131 and I. Chinchilla et al. 2865.

Additional specimens examined.

Costa Rica-Panama. • Puntarenas-Chiriquí: Coto Brus-Renacimiento, línea fronteriza entre Cerro Quijada del Diablo y Cerro Pando, entre mojones N. 336–338 , 8°54'51.9"N, 82°43'59.13"W, 2205 m, bosque muy húmedo premontano, epífita en bosque primario, “ in itinere per limitem Costa Rica et Panama inter montis Quijada del Diablo et montis Pando ”, 19 April 2011, fl. in cult. 14 March 2022, D. Bogarín, D. Jiménez & A. P. Karremans 8632 ( JBL - spirit, E 1542 !, Fig. 5 B ) . Costa Rica-Panama. • Puntarenas-Chiriquí: Coto Brus-Renacimiento, línea fronteriza entre Cerro Quijada del Diablo y Cerro Pando, entre mojones N. 336–338 , 8°54'51.9"N, 82°43'59.13"W, 2205 m, bosque muy húmedo premontano, epífita en bosque primario, “ in itinere per limitem Costa Rica et Panama inter montis Quijada del Diablo et montis Pando ”, 19 April 2011 fl. in cult. 8 October 2021, D. Bogarín 8637, D. Jiménez & A. P. Karremans ( JBL - spirit, A 0558 !) . Costa Rica. • Puntarenas: Coto Brus, Sabalito, Zona Protectora Las Tablas, 13 km al noreste de Lucha, Sitio Coto Brus, entre Río Surá y Quebrada Sutú, Finca de Miguel Sandí , 8°56'46.1"N, 82°44'30.9"W, 1778 m, bosque pluvial montano bajo, epífitas en potreros arbolados, 6 June 2010, A. P. Karremans 2829 & D. Bogarín (Fig. 6 I ) . • Puntarenas: Buenos Aires, Buenos Aires, camino a Cerros Utyum , 9°18'04.93"N, 83°12'51.59"W, 2157 m, bosque pluvial montano bajo, epífitas en bosque secundario, 16 January 2017, D. Bogarín, M. Cedeño, I. Chinchilla, M. Díaz, E. Kaes, A. P. Karremans, P. Lehmann & O. Zúñiga 12131 [ JBL - spirit, A 0375 ! (fl. in cult. 9 May 2019), A 0877 ! (fl. in cult. 21 March 2023)] . • Puntarenas: Buenos Aires, Buenos Aires. Olán, en el sendero de la Transutyum, después del arbolado , 9°17'56.67"N, 83°12'54.12"W, 2107 m, bosque pluvial montano bajo, bosque primario, epífita, a media luz, 16 January 2017, I. Chinchilla, D. Bogarín, A. P. Karremans, M. Díaz-Morales, M. Cedeño & E. Kaes 2865 [ JBL - spirit, A 0187 ! (fl. in cult. 19 December 2018), K 0154 ! (fl. in cult. 18 agosto 2021), E 1543 ! (fl. in cult. 14 marzo 2022), Fig. 6 R ] . • Puntarenas: Buenos Aires, Potrero Grande, Altamira, Parque Internacional La Amistad, Sector Altamira, sendero al Valle del Silencio, base del Cerro Hoffmann , 9°05'05"N, 82°58'42"W, 2450 m, 15 May 2022, A. P. Karremans, I. Chinchilla, L. Oses, G. Rojas-Alvarado & F. Vargas Acuña 9135 [ JBL - spirit, A 0934 ! (fl. in cult. 25 July 2024), A 0937 ! (fl. in cult. 25 July 2023), K 0412 ! (fl. in cult. 3 April 2024)] . • Puntarenas: Coto Brus, Sabalito, Zona Protectora Las Tablas, 13 km al noreste de Lucha, Sitio Coto Brus, entre Río Surá y Quebrada Sutú, Finca de Miguel Sandí , 8°56'46.1"N, 82°44'30.9"W, 1778 m, bosque pluvial montano bajo, epífitas en potreros arbolados, 6 June 2010, D. Bogarín & A. P. Karremans 7718 (Fig. 6 E, H, N ) . Same locality and date, D. Bogarín 7742 & A. P. Karremans (Fig. 6 B ) . Same locality and date, D. Bogarín 7743 & A. P. Karremans (Fig. 6 D ) . • Límite entre Limón y Puntarenas: Talamanca-Buenos Aires, Bratsi-Potrero Grande, Parque Internacional La Amistad, Sector Altamira, sendero al Valle del Silencio, Cerro Hoffman, sobre la divisoria de aguas , 9°05'38.2"N, 82°58'37.73"W, 2553 m, bosque pluvial montano, 14 August 2012, fl. in cult. 7 February 2019, D. Bogarín 9806, M. Fernández, J. Godínez, A. P. Karremans, J. Kruizinga & C. Smith ( JBL - spirit, A 0216 !, Fig. 6 F, O ) . • Puntarenas: Coto Brus, Sabalito, Zona Protectora Las Tablas , 13 km al noreste de Lucha, Sitio Coto Brus , 8°56'46.1"N, 82°44'30.9"W, 1778 m, finca “ El Capricho ” de Miguel Sandí, principalmente en árboles de Quercus en las lomas y potreros al margen del río Sutú, bosque muy húmedo premontano, 6 October 2010, M. Fernández 382, R. L. Dressler, D. Bogarín & F. Pupulin [ JBL - spirit, D 5618 !, A 0209 ! (fl. in cult. 5 February 2019), Fig. 6 G, L ] . Same locality and date, M. Fernández 385, R. L. Dressler, D. Bogarín & F. Pupulin (Fig. 6 A ) . • Puntarenas: Buenos Aires, Buenos Aires, Olán, camino a los cerros Utyúm en bosque maduro , 9°18'04.54"N, 83°12'48.72"W, 2129 m, bosque pluvial montano bajo, 16 January 2017, M. Díaz 305, D. Bogarín, M. Cedeño, I. Chinchilla, A. P. Karremans, P. Lehmann y O. Zúñiga [ JBL - spirit, A 0560 ! (fl. in cult. 8 October 2021), A 0575 ! (fl. in cult. 3 November 2021), Fig. 6 S – T ] . • Puntarenas: Buenos Aires, Potrero Grande, Altamira, Parque Internacional La Amistad, Sector Altamira ,, sendero al Valle del Silencio, ca. 1 km después de Cerro Quemado , 9°04'38.7"N, 82°58'37.4"W, 2284 m, bosque pluvial montano, 14 August 2012, A. P. Karremans 5685, D. Bogarín, M. Fernández, J. Godínez, J. Kruizinga & C. M. Smith (Fig. 6 M ) . • Puntarenas: Coto Brus, Sabalito, Zona Protectora Las Tablas, 13 km NE of Lucha, Sitio Coto Brus, finca Sandí “ El Capricho ” , 8°56'46.1"N, 82°44'30.9"W, 1778 m, epiphytic, mostly on Quercus sp. in pastures and along the river Sutú, wet premontane forest, 6 October 2010, F. Pupulin 7887, D. Bogarín, R. L. Dressler & M. Fernández (Fig. 6 Q ) . Same locality and date, fl. in cult. 6 December 2012, F. Pupulin et al. 7910 ( JBL - spirit, D 5640 !, Fig. 6 K ) . Same locality and date, F. Pupulin et al. 7893 ( JBL - spirit, Fig. 6 J ) . • Puntarenas: Coto Brus, Sabalito, Finca Las Tinieblas, propiedad de Billen Gamboa, filas hacia el norte del potrero principal . 8°55'25.6"N, 82°44'55.1"W, altitud 1975 m. Bosques maduros dominados por Quercus spp. 10 December 2023, fl. in cult. 9 September 2024, L. Álvarez 1404, B. Gamboa, M. Mata-Quirós, G. Ramírez, F. Rodríguez, J. H. Flores ( JBL - spirit!) .

Eponymy.

Honoring the English botanist Alec M. Pridgeon, renowned worldwide for his seminal research on orchid anatomy and phylogenetics, including Pleurothallidinae. A founding editor of the journal Lindleyana and main editor of the monumental series of books Genera Orchidacearum, which laid the foundation for the contemporary understanding of orchid relationships.

Phenology.

Plants in cultivation have been recorded in flower virtually year-round, with flowering peaks in November and February, coinciding in Costa Rica with the end of the rainy season and the beginning of the dry season.

Distribution and ecology.

Currently known only from southern Costa Rica and western Panama, where plants grow either epiphytically or terrestrially on organic matter in oak forests at high elevations, around 1800–2550 m. Pleurothallis pridgeoniana is locally abundant at high elevations on the Cordillera de Talamanca, in the Puntarenas ( Costa Rica) and Chiriquí ( Panama) provinces respectively. This notoriously prolific species is often found forming large pending mats or clumps in primary and mature forests.

Notes.

Pleurothallis pridgeoniana is easily recognized by the large bushy habit derived from constitutive prolification, in which each ramicaul eventually produces vegetative growths apically, thus originating chains of multiple ramicauls (Fig. 7 ). The new species seems to be vegetatively most similar to P. vinealis from Colombia and Ecuador, which Luer (2005) distinguished by its unique vine-like habit, with prolific ramicauls that twine and branch, apparently attaining more than a meter in length. From P. vinealis , P. pridgeoniana can be distinguished by the significantly shorter plants, up to 30 cm long (vs. exceeding a meter), the shorter ramicauls 7.5–26.0 cm (vs. up to 40 cm long), the significantly smaller flowers, dorsal sepal 6.8–7.0 × 3.3–3.4 mm (vs. 11–14 × 4.5–5.5 mm), synsepal 5.5–6.5 × 4.1–4.2 mm (vs. 11–14 × 4.5–5.5 mm), lip triangular-ovate (vs. oblong), 2.4–2.6 × 1.6–1.7 mm (vs. 5.5–6.5 × 3 mm). The flowers are transparent yellow, with a rose to purple suffusion (vs. brown), the lip is triangular-ovate (vs. oblong) the margins glandular (vs. denticulate), slightly raised but lacking a central sulcus (vs. notably sulcate).

Florally, the non-prolific Pleurothallis applanata Luer & Dalström and P. undulata Poepp. & Endl. (following Luer 2005) are reminiscent of P. pridgeoniana . The new species can be distinguished from the former, a species from Ecuador and Peru, by longer ramicauls (up to 26 vs. 12 cm), the smaller flowers, with shorter sepals (5.5–7.0 vs. 9.5–10.0 mm long), narrower (0.6–0.7 vs. 1 mm long), glandular petals, with erose margins (vs. smooth, entire), the shorter and narrower (2.4–2.6 × 1.6–1.7 vs. 4.5 × 2.2 mm) lip, shortly apiculate (vs. obtuse), and erect, subrectangular column, (vs. dorsally compressed on a plane with the lip). From the latter, endemic to Peru, it can be distinguished by the shorter (5.5–6.5 vs. 6–9 mm) synsepal, naturally drooping petals (vs. horizontal to elevated), and the shorter lip (2.4–2.6 vs. 3.0–4.0 mm), with a pair of shoulder-like basal lobes (vs. lip unlobed).

Figures

Figure 5. Pleurothallis pridgeoniana Karremans, Bogarín & Pupulin A habit showing the typical prolific vegetative growth B prolific growth featuring a single flower on a secondary ramicaul C flower D dissected perianth (dorsal sepal, two lateral petals, two lateral sepals fused into a synsepal and a view of the lip) E lip F column and lip, lateral view G column, lip and ovary, lateral view H anther cap and pollinarium. LCDP prepared by APK based on Karremans 7600 (A, C – H) and Bogarin 8632 (B).

Figure 6. Floral variation in Pleurothallis pridgeoniana A Fernández 385 B Bogarin 7742 C Karremans s. n. D Bogarín 7743 E Bogarín 7718 F Bogarín 9806 G Fernández 382 H Bogarin 7718 I Karremans 2829 J Pupulin 7893 K Pupulin 7910 L Fernández 382 M Karremans 5685 N Bogarin 7718 O Bogarin 9806 P Karremans s. n. Q Pupulin 7887 R Chinchilla 5865 S, T Diaz 305. Photographs by the authors.

Figure 7. Pleurothallis pridgeoniana Karremans, Bogarín & Pupulin in its natural habitat in Valle del Silencio on the southern Talamanca range in Costa Rica, close to the border with Panama A general overview of the prolific growth habit and asexual production of new units B detail of a flowering plant. Photographs by APK.