Pleurothallis matrisilvae Karremans, J. Gange & 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 matrisilvae Karremans, J. Gange & Pupulin sp. nov.

Type.

Costa Rica. • Cartago: El Guarco, San Isidro, Madreselva, Tres de Junio, Carretera Interamericana Sur , 9°40'31"N, 83°53'33"W, 2530 m, bosque pluvial montano, en bosque secundario de robles a orillas de la carretera, 5 March 2022, fl. in cult. 8 March 2022, A. P. Karremans & J. Gange 9036 (holotype: JBL - spirit, M 0058 !; Fig. 3 ) .

Diagnosis.

The flower is superficially similar to that of Pleurothallis bothros , however the new species may be distinguished by the prolific habit (vs. non-prolific), ramicauls linear, very thin throughout (vs. ramicauls subclavate, notably thickened apically), bearing 1–4 open flowers (vs. many, usually + 10, simultaneous flowers), the longer flower segments (dorsal sepal 7.4–7.6 vs. 6.5–6.6 mm, lateral sepals 6.6 vs. 6.0 mm, petals 5.6–5.7 vs. 3.8–4.0 mm, lip 4.1–4.3 vs. 3.1–3.5 mm), the lanceolate petals (vs. oblong) and the black flecks on the pedicel, ovary, and external surface of the sepals (vs. no flecks).

Description.

Epiphytic, caespitose, constitutively prolific, suberect to erect herbs, up to 30 cm tall. Roots flexuous, thin, ca. 1 mm in diameter, densely spaced, appearing fasciculate. Ramicauls erect to suberect, slender, up to 28 cm long, covered by tubular sheaths close to the base, tightly adpressed, up to 5 cm long. Leaves spreading, glossy, dark green, coriaceous, sessile, ovate-cordate with downturned margins, acuminate, blades of the primary ramicaul 4.0–7.5 × 2.0– 3.8 cm. Inflorescences persistent, forming few to several successive multi-flowered coflorescences, each producing a single open flower, up to 4 different coflorescences bearing simultaneous single flowers, typically 1 or 2, subtended by a nearly prostrate or suberect spathe which appears deeply torn during and after anthesis, ca. 1 cm long; pedicels terete, pale gray-yellow, with irregular black flecks. Ovary clavate, 4.5–4.7 mm long, gray-green and suffused with yellow, similarly marked with black. Flowers spreading, yellow. Dorsal sepal elliptic-ovate, slightly concave, obtuse, 3 - veined, with irregular black flecks on its adaxial surface, 7.4–7.6 × 4.5 mm, apiculate. Lateral sepals connate in an oblong, slightly concave synsepal, obtuse, 4 - veined, 6.6 × 5.8–5.9 mm. Petals linear-lanceolate, oblique, acute, 1 - veined, 5.6–5.7 × 1.0– 1.1 mm. Lip triangular-ovate, resting on the synsepal, 4.1–4.3 × 2.7–2.8, margins raised, apex slightly recurved, acute, glenion a deep cavity between the raised lateral margins. Column straight, transversely subrectangular, 1.7–1.9 mm long, apically 2.1 mm wide, with a ca. 1 mm column foot, the anther and stigma apical. Anther cap ovate, cucullate, obtuse at the base, bilobed apically, 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 & J. Gange 9036, D. E. Mora s. n., and D. Bogarín et al. 13652.

Additional specimens examined.

Costa Rica. • Cartago: Cordillera de Talamanca , alt. 2400 m, D. E. Mora s. n. ( USJ!) . Cartago: El Guarco, Cañón, Bajo Gloria, Centro Ecoturístico Los Robles, inicio del sendero Danta , 9°42'14.97"N, 83°54'55.96"W, 2332 m, epífitas en árboles alrededor de los senderos, bosque muy húmedo montano bajo, 12 February 2022, fl. in cult. 19 April 2022, D. Bogarín 13652, S. Bogarín, M. Bonilla & O. A. Pérez-Escobar ( JBL - Spirit, E 1544 !; Fig. 4 B ) . • San José-Cartago: Dota-El Guarco, Copey-Cañon, ca. 100 m deviation point in front of the Liceo Rural of Cañon, slopes of Cerro Artieda , 9°40'52.44"N, 83°55'10.04”W, 2545 m, epiphytic on scattered trees in pastures and remnants of secondary woods, 3 March 2022, fl. in cult. 21 April 2022, F. Pupulin 8951 & D. Bogarín ( JBL - spirit, E 1545 !) .

Eponymy.

From the Latin “ matrisilva ”, mother-forest, honoring the locality Madreselva, where the type specimen was collected.

Phenology.

Flowering has been recorded at least from November to April, which approximately corresponds to the end of the rainy season and the first months of the dry season in Costa Rica.

Distribution and ecology.

Currently known only from central Costa Rica, where the species is found growing either epiphytically, mainly on oaks, or terrestrially, on the leaf mulch rich ground, in montane or cloud forests at high elevations around 2300–2550 m (Fig. 4 C ). Pleurothallis matrisilvae is not a particularly rare species, but all currently known specimens were collected in the same general area on the Cordillera de Talamanca in the province of Cartago.

Notes.

Contrary to the other species described here, Pleurothallis matrisilvae is typically prolific when growing as an epiphyte, while it is mostly non-prolific when found growing on top of organic matter on the ground. The new species is morphologically similar to P. bothros and its relatives. It, however, grows at higher elevations and is distinguished by the often-prolific habit, the thin ramicauls and especially by having mainly one or two flowers open at once, which is unlike all other species in the P. bothros group ( Karremans and Jiménez 2018). It is most similar to Pleurothallis bothros , which is endemic to the Cordillera de Guanacaste and Tilarán in the northern provinces of Alajuela, Guanacaste, and Puntarenas in Costa Rica, where it grows at mid elevations between 750 and 1750 m. The other two members of the P. bothros group, P. hawkingii Karremans & J. E. Jiménez and P. vide-vallis Karremans & J. E. Jiménez can be easily separated from P. matrisilvae by the non-prolific habit (vs. prolific), three or more flowers opening simultaneously (vs. typically one or two), their pale yellow flowers suffused with a pink (vs. solid yellow), the broad, oblique petals (vs. narrow, straight), and the proportionally much larger lip. Both are only known from the Cordillera de Guanacaste in northern Costa Rica ( Karremans and Jiménez 2018).

Figures

Figure 3. Pleurothallis matrisilvae Karremans, J. Gange & Pupulin A habit, showing some ramicauls bearing flowers and others bearing new growths B single leaf with flower C flower D dissected perianth (dorsal sepal, two lateral petals, lateral sepals fused into a synsepal and two views of the lip) E column and lip, lateral view F column and ovary, lateral and ventral views G two views of the anther cap and pollinarium. LCDP prepared by APK based on Karremans 9036.

Figure 4. Pleurothallis matrisilvae Karremans, J. Gange & Pupulin composite A the florally similar P. bothros (JBL - sn) B bearing a single open flower and several developing buds (Bogarín 13652) C epiphytic plant in its natural habitat in Madreselva on the central Talamanca range, showing the prolific growth and asexual production of new units. Photographs by APK.