Introduction

The Vanilloideae are one of the five subfamilies of Orchidaceae and their distribution is worldwide despite being significantly less diverse in species numbers than the ubiquitous members of the Orchidoideae and Epidendroideae subfamilies. Even though they represent only a small component of the Costa Rican flora, our knowledge on the country’s Vanilloideae has grown significantly in the last two decades. The curated compilations of the Costa Rican orchid species (Dressler 2003, Pupulin 2002, Soto Arenas & Dressler 2003) recorded the presence of only two genera belonging to this subfamily occurring in the country: Cleistes Rich. ex Lindl. and Vanilla Mill.

Vanilla is a Pantropical genus of ca. 120 accepted species (Karremans et al. 2020), widely appreciated on account of the world-famous vanilla flavoring that is extracted from the fruits of some of its species (Bouetard et al. 2010). Vanilla are taxonomically challenging due to the sparsity and poor state of flower material in herbarium specimens (Lubinsky et al. 2008, Soto Arenas & Dressler 2010) and their unusually broad geographic distributions (Karremans et al. 2020). In recent compilations of the country’s orchid flora, Pupulin (2002) and Soto Arenas & Dressler (2003) recorded seven species of Vanilla occurring in Costa Rica; additionally listing 3-4 undescribed taxa. Four species were formally added by Soto Arenas & Dressler (2010), three of them new to science and one being a new country record. Two more taxa were published by Azofeifa-Bolaños et al. (2017) and another shortly after by Karremans & Lehmann (2018). We now accept 13 species of Vanilla naturally occurring in Costa Rica (Karremans et al. 2020).

Among the Vanilloideae, only the genus Cleistes has been listed for the Costa Rican flora other than Vanilla. The 60 or so accepted species of Cleistes are exclusively Neotropical. Its distribution is primarily South American, with the highest species diversity in Brazil and extending north up to Costa Rica in Central America (Batista et al. 2023). A single species has typically featured in the flora of Costa Rica, often under the name Cleistes rosea Lindl., a well-known and widespread species that has been reported to occur from Costa Rica downward to Bolivia and Brazil (Batista et al. 2023). However, Christenson (1992) noted that populations of Cleistes in central Costa Rica differed from the true C. rosea and segregated these under the name Cleistes costaricensis Christenson. Consequently, the name C. costaricensis replaced the concept of C. rosea in the country and the latter ceased to appear in the Costa Rican flora (Pupulin 2002, Dressler 2003).

A recent integrative study on the identity of the species and variations in the C. rosea complex once again confirmed the separation of populations from central Costa Rica into a different species, C. costaricensis, which is well isolated from its South American counterparts. However, our explorations of the Costa Rican southern Pacific range of the Talamanca mountains has revealed the presence of a second species of Cleistes in the country. These south ern plants are quite different from those from the central valley, bearing large open flowers typical of the true C. rosea. Therefore, after three decades of exclu sion, C. rosea returns to the orchid flora of Costa Rica. We characterize and illustrate the species here based on living material.

Furthermore, recent records have confirmed the presence of a third genus of Vanilloideae occurring in Costa Rica: Epistephium Kunth (Karremans 2022, Karremans et al. 2012). Epistephium is a Neotropical genus widely distributed from Belize to Paraguay, with most of its 28 currently recognized species localized in South America, especially Colombia and northeastern Brazil (Cameron 2003). The broadly distributed E. ellipticum R.O.Williams & Summerh., the only member of this genus to extend into Central America, grows as a terrestrial herb in the shaded understory in lowland primary forests along the Caribbean coast. Despite having been collected as far north as Belize since almost a century (McLeish et al. 1995), this tiny understory species, easily confused with other under story vegetation, has so far rarely been recorded in other Central American countries. It was collected for the first time in Costa Rica close to the border with Panama in 1995 (Karremans et al. 2012), and only rediscovered in 2022 when a flowering plant was photographed by a tourist close to the border with Nicaragua and posted on iNaturalist (Karremans 2022). A full color plate and description of this elusive taxon based on Costa Rican material is presented for the first time here.

Cleistes rosea Lindl., Gen. Sp. Orchid. Pl.: 410. 1840. Pogonia rosea (Lindl.) Rchb.f., Xenia Orchid. 2: 89. 1865. Pogonia rosea (Lindl.) Hemsl., Biol. Centr.-Amer., Bot. 3: 304. 1884, nom. superfl.

TYPE: GUYANA: “Savannahs adjacent to the lake Capooey, Arabisee Coast of Essequibo”, R.H. Schom burgk s.n. (holotype: K-L barcode K000079712!; re cord of type: AMES-00024325!). Discussion on typification below.

Heterotypic synonyms (following Batista et al. 2023):

Epistephium monanthum Poepp. & Endl., Nov. Gen. Sp. Pl. 1: 53. 1836. Pogonia monantha (Poepp. & Endl.) Schltr., Repert. Spec. Nov. Regni Veg. Beih. 9: 121. 1921, nom. illeg. (non Pogonia monantha Barb. Rodr., Gen. Spec. Orchid. 1: 167. 1877 = Cleistes mo nantha (Barb. Rodr.) Schltr., Arch. Bot. São Paulo 1: 179. 1926).

TYPE: PERU. Loreto: Huánuco, between Cuchero and Chihuamecala, Dec 1829, E.F. Poeppig 1601B (lectotype designated by Garay (1978): W-R 00007715).

Pogonia acuminata Schltr., Repert. Spec. Nov. Regni Veg. Beih. 7: 40. 1920. nom. illeg. Cleistes acuminata Schltr., Arch. Bot. Sao Paulo 1: 180. 1926.

TYPE: COLOMBIA. Antioquia: c. 1000 m, s.d., M. Madero s.n. (holotype: B destroyed; lectotype, desig nated by Batista et al. (2023): Mansfeld (1929), table 10, fig. 35 (reproduction of Schlechter’s drawing of the species, probably from the holotype)).

Pogonia venusta Schltr., Repert. Spec. Nov. Regni Veg. Beih. 7: 42. 1920. Cleistes venusta (Schltr.) Schltr., Arch. Bot. Sao Paulo 1: 180. 1926.

TYPE: COLOMBIA. Cauca: c. 1500 m, s.d., M. Madero s.n. (B destroyed); lectotype, designated by Batista et al. (2023): Mansfeld (1929), table 10, fig. 38 (reproduction of Schlechter’s drawing of the species, probably from the holotype).

Cleistes aboucharii Szlach., Kolan. & Baranow, Mater. Orchid Fl. Colombia 3: 167. 2020.

TYPE: COLOMBIA. Valle del Cauca: alrededores de Cali, ramales de la Cordillera Occidental, 1400 bm, Jan 1968 (fl.), A. Abouchar s.n. (holotype: COL-119652).

Terrestrial plant up to 50 cm tall. Roots thick, tu berous, 3 mm in diameter, to 3 cm long. Stem erect, cylindrical, hollowed, 3.5-5.5 mm in diameter, brown ish to purplish basally. Leaves ovate-lanceolate, acute, erect, chartaceous, glaucous, with the base clasping the stem, slightly concave, 4.5-9.0 × 2.0-3.6 cm, the apex acute, forming a very small hooded tip, the basal leaf reduced to a small ca. 2 × 1 cm sheath. Inflorescence a raceme with a single flower open at a time, and a few more opening several days afterwards in slow succes sion, subtended by foliaceous, ovate-lanceolate, acute, erect, chartaceous, glaucous bracts, 5.1-10.0 × 1.8-3.5 cm, the apical one smaller, the base with its base clasp ing and decurrent with the stem for 1-2 cm, the apex acute, forming a very small hooded tip; rachis 7.5 cm long and 2.5 mm in diameter; the remnant of the axis in a form a 1 mm long filament at the base of the apical ovary, opposite to the bract. Ovary pedicellate, 2 cm long, 3 mm wide, cylindrical, terete. Flowers resupi nate, with sepals spreading, petals and lip flanking the porrect lip and column. Dorsal sepal free, 6.3 × 1.1 cm, ensiform, acute, with incurved margins, pinkish with light green at the base, 12-veined. Lateral sepals free, 6.0 × 1.1 cm, ensiform, acute, with incurved mar gins, pinkish on the adaxial surface and lighter on one side, light green abaxially and slightly pinkish laterally at the base. Petals free, 6.0 × 1.5, oblanceolate, apex acute, recurved, slightly asymmetrical, wavy, light pink basally and magenta to the apex, 12-veined. Lip oblong, 5.5 × 2.5 cm, obtuse, blade white with pinkish to purplish stripes at the apex, 13-veined, yellow along the center of the crest, lateral margins forming a tube around the column, blade longitudinally 2-crested, the first basal third of the crests with a common thickened 1.5 mm high base, the crests at the base of the blade 7 mm wide when spread, with recurved margins, the crests above the 2/3 of the blade 4 mm wide, forming multiple lamellae that progressively becomes irregu lar and warty towards near the apex. Column clavate, whitish, 3.4 cm long, 3 mm wide basally, 7 mm wide apically, the base with a pair of pear-shaped glands, clinandrium lacerate with the dorsal and lateral margin longer, the lateral ones forming acute teeth. Anther ob trapezoid, 9 × 8 mm, whitish, with a 5 mm wide loose mass of pollen which does not form a pollinia. Fruit cylindrical, glaucous, 4.5 cm long, 7 mm thick, with falling perianth. This description is based on the cited Costa Rican materials only.

Specimens studied: Costa Rica. San José: Pérez Zeledón, Paramo, La Ese, 9°26’33”N 83°42’50”W, 1340 m, sobre el corte de la carretera al costado de la Escuela La Ese, 29 Jul 2022, A.P. Karremans 9342, I. Chinchilla & G. Rojas-Alvarado (JBL-spirit, Fig. 1).

Distribution and habitat: The specimen here documented from Costa Rica is the northernmost in this species’ range. It is also known to occur in Panama, Colombia, Venezuela, Ecuador, Peru, Trinidad, the Guianas and northern Brazil (Batista et al. 2023). In Costa Rica the species is only known from the southern Pacific range of the Talamanca mountains. It appears to be rather rare, we found a single small population on a road-cut in an open area dominated by grasses, fully exposed to the sun at 1340 m in elevation, in a premontane rain forest zone. However, photographs by locals suggest C. rosea plants occasionally sprout out in different locations flanking the El General valley in the south of the country, and there are probably a few isolated populations.

Phenology: In the field, plants have been document flowering and fruiting in July.

Etymology: From the Latin roseus, meaning rose-colored, referring to the color of the flowers.

Notes: The correct typification of C. rosea has been a matter of recent debate. Meneguzzo et al. (2020) selected a specimen in Lindley’s herbarium at Kew (K-L barcode K000079712) as lectotype, but according to Batista et al. (2023) this is superfluous as a previous lectotypification was made, without explicitly stating it, by Garay (1978). We must agree with the latter that indeed Garay’s unintended typification suffices the requirements. Nevertheless, we disagree with both teams that a lectotype is actually necessary. We argue there is no ambiguity about the status of this specimen as holotype given that it is the only specimen in Lindley’s own herbarium which corresponds with the protologue, is accompanied by the typical floral sketches, and, most importantly, is clearly labeled (in the author’s handwriting) as the species he is describing under “Cleistes rosea m.”, in other words “my Cleistes rosea”. We disagree with the interpretation that Schomburgk’s specimen in Paris (barcode P00367101) represents an isotype or isolectotype (Batista et al. 2023, Meneguzzo et al. 2020). Lindley published Cleistes rosea in 1840 and Romero-González (2005) points out that the type specimen was probably collected by Schomburgk be tween 1836 and 1837, which is consistent with the date of publication. Both definitively exclude the pos sibility that type material of C. rosea could be collected in 1845, and therefore that the Paris specimen is, strictly speaking, part of the original materials. It is important to note that the 1845 date on the material at P is likely mistaken altogether given that Robert H. Schomburgk had already returned to England by then (Rivière 2006). Either way, it is not possible to link this specimen with the original materials of C. rosea.

Batista et al. (2023) thoroughly revised the Cleistes rosea complex and recognized three var ieties. Based on their classification, the material collected in Costa Rica corresponds to Cleistes rosea var. rosea. It is distinguished from C. rosea var. guianensis Sambin & J.A.N.Bat. and C. rosea var. bue naventurae (Szlach. & Kolan.) J.A.N.Bat. & C.Castro by having sepals internally vinaceous, pinkish-purple, pinkish-brown or magenta (vs. sepals internally light green, greenish-yellow, or greenish-brown in the other two varieties), petals purple, purplish-pink or magenta with the base sometimes slightly lighter (vs. petals mauve to dark mauve, base pale mauve; and petals white, base cream-colored to light green, respectively), the lip not depressed (vs. lip always suddenly depressed at the – of its length in C. rosea var. buenaventurae).

Cleistes rosea var. rosea is widely distributed, occurring in Costa Rica, Panama, Colombia, Venezuela,Trinidad,Guyana, EcuadorandPeru.Cleistes rosea var. guianensis is restricted to French Guiana while C. rosea var. buenaventurae is restricted to the western side of the Cordillera Occidental in the Pacific/Chocó region of Colombia. The morphologically most similar species is C. castaneoides Hoehne. According to Batista et al. (2023), C. rosea is distinguished form the latter by having a concave leaf, invariable decurrent, the size as or larger than the floral bracts (vs. leaf convolute, clasping the stem, not decurrent, and shorter than or up to the same length as the floral bracts), sepals patent with at most only reflexed apex (vs. sepals markedly reflexed in fully open flowers), the anther white (vs. pale mauve to intense purplish-pink). In Costa Rica, Cleistes rosea is easily distinguished form the only other species of the genus, C. costaricensis Christenson (Fig. 2) by the flowers with spreading sepals (vs. sepals almost closed), petals acute to acuminate (vs. acute), lip oblong, the apex pinkish to purplish and obtuse (vs. lip shortly trilobate, with an oblong fimbriate purplish apex with out stripes), anther white (vs. purplish), column white (vs. purplish).

Epistephium ellipticum R.O. Williams & Summerh., Bull. Misc. Inform. Kew 1928(4): 145. 1928.

TYPE: Trinidad. Valencia Road, Mora forest end, Sept 1926, Freeman, Williams & Cheesman s.n. (holotype: TRIN-11324!; isotype: K (seen by McLeish et al. 1995 and Szlachetko et al. 2020, not found by us); drawing of type: AMES barcode 00099136!).

Heterotypic synonyms:

Epistephium tenuifolium Mansf. ex Hoehne, Flora Brasilica 8: 12: 2: 42. 1945, nom. inval.

TYPE: Brazil. Pará, Belém mata de terra firme entre Catú e Providência, 5 Nov 1914, A. Ducke 15522 (RB 00542607!).

Epistephium minutum Barbosa-Rodrigues, Flora Bra silica 8: 12: 2: 42. 1945, nom. nud.

A terrestrial, sympodial herb, up to 30 cm tall. Roots elongate, up to 12.5 cm long, 3-4 mm in diameter, tere te, fleshy. Stem simple or branched, erect, terete, fleshy; internodes 5-50 mm long, 1.5-2.0 mm in diameter. Leaves 2-9, short-petiolate, conduplicate, soft-textured; petiole canaliculate, fleshy, 1-5 mm long; blades ellip tic to obovate, attenuate, acute to acuminate or caudate, longer than internodes, reticulate venation, 5-7-vei ned, 1.0-6.5 × 0.5-2.5 cm. Inflorescence a terminal or axillary raceme, abbreviated, with 2-5 successive flowers, 1 open at a time. Floral bracts sessile, short, ovate, acuminate, concave, coriaceous, green to reddish, 2.0-3.5 × 1.0-2.1 mm; rachis shortened. Pedicellate ovary straight to lightly arcuate, terete, papillose, green to reddish, 9-14 mm long, 1.0-1.5 mm in diameter, with a shortly dentate calyculus, ca. 1 mm long. Flowers re supinate, erect, spreading, showy, thin, soft-textured, with sepals, petals and column white, lip white, with adaxially and abaxially blade magenta on the veins and the all apical third, and pollen whitish. Dorsal sepal oblanceolate, attenuate, acute, lightly concave, margins flat, apically recurved in natural position, 3-veined, 26.8 × 3.0 mm. Lateral sepals oblanceolate, attenuate, acute, lightly concave, margins flat, apically recurved in natu ral position, 3-veined, 25.0 × 4.5 mm. Petals oblanceo late, attenuate, acute, lightly concave, porrect, apically lightly recurved in natural position, 3-veined, 26.3 × 5.5 mm. Lip free, spatulate, unguiculate, emarginate, concave, tubular, trumpet-shaped, porrect, when spread out 27 × 17 mm; the claw canaliculate, inconspicuously pubescent, 12.0 × 1.4 mm; the blade bilobed, subrhom bic, rounded, emarginate, with a central vertical, raised, tapered, fleshy thickening, apically thickly villose, 15 × 17 mm, ca. 21-veined, the veins impressed; lobes su bequal, semi-ovate, acute, margins overlapping, cover the column, basally entire, apically undulate, incurved, 15 × 8.5 mm. Column subterete, slender, slightly arcua te, lightly trilobed at apex, ventrally flattened, glabrous below the stigma, 16.5-20.0 × 1.5-2.0 mm. Anther incumbent, obovoid, attached to the clinandrium with entire margins, ca. 1.3 × 1.5 mm. Pollen a soft, sticky granular mass. Stigma simple, convex. Rostellum sub quadrate, porrect, slightly concave, ca. 1.5 × 1.3 mm. Fruits a linear capsule, trilobed, trisulcate, apically tapering, 19-27 × 2-3 mm, with a shortly dentate calyculus, ca. 1.0 mm long. This description is based on the cited Costa Rican materials only.

Distribution and habitat: This broadly distributed spe cies has been shown to occur in the following coun tries (earliest reference we could find is cited): Belize (McLeish et al. 1995), Guatemala (Archila Morales et al. 2018), Costa Rica (Karremans et al. 2012), Colombia (Betancur et al. 2015), Peru (Karremans et al. 2012), Venezuela (Schultes 1957), French Guiana (Sambin & Ravet 2021), Guyana (Funk et al. 2007), Brazil (Schultes 1957) and Trinidad (Schultes 1957). In Costa Rica, plants of Epistephium ellipticum grow in the understory of very humid lowland tropical forests of the Caribbean, between 50 and 100 m in elevation, in the Maquenque National Mixed Wildlife Refuge and Gandoca-Manzanillo Wildlife Refuge.

Phenology: In the field, plants have been document flowering and fruiting in March, April and September.

Etymology: From the Latin ellipticus, meaning elliptic, in allusion to the elliptical leaves typical of the species.

Specimens studied: Costa Rica. Alajuela: San Carlos, Pital, Boca Tapada, Refugio Nacional de Vida Silvestre Mixto Maquenque, reserva de La Laguna del Lagarto Eco-Lodge, a la orilla del sendero, 10°40’52.0”N 84°10’33.5”W, 65 m, 29 abr 2022, A. P. Karremans et al. 9050 (JBL-spirit; Fig. 3). Limón. Talamanca, Sixaola, Gandoca, El Llano entre Filas Manzanillo y Río Mile Creek, 9°37’00.0”N 82°41’00.0”W, 50-100 m, 27 mar 1995, G. Herrera & E. Sandoval McCarthy 7605 (CR, MO).

Notes: Epistephium ellipticum is the only species in the genus known to occur in Central America. Plants of this species are terrestrial herbs up to 30 cm long, erect, sympodial, with tubular, fleshy roots, short stems, covered by the sheaths of short-peciolate leaves, the blades elliptic, thin, with soft-texture and reticulate venation, showy, ephemeral, fragile, white flowers, with magenta lip on the veins and the apical third. Without flowers, E. ellipticum plants are dif ficult to spot and even recognize as an orchid. Due to their lustrous leaves with channeled petiole and small stature, plants of this species can easily go unnoticed in the field by its similarity to young individuals of the families Costaceae, Commelinaceae, and even Primulaceae.

A collection by Ducke at RB bears a label with the name Epistephium tenuifolium Mansf. and another with the name Epistephium minutum Barb.Rodr., neither having been formally published by those authors. Hoehne (1945) accepted the name E. tenuifolium providing a description in Portuguese, and placing E. minutum in synonymy. However, by then, a Latin description was a requirement for formal validation and both names are therefore still invalid. We agree with Schultes (1957) in considering E. tenuifolium and E. minutum conspecific with E. ellipticum, but don’t agree in ascribing E. minutum to Hoehne as ex author given he merely listed the name as a synonym.

The Epistephium material from Costa Rica agrees well with the protologue and type of E. ellipticum. However, Costa Rican plants have up to five flowers (vs. 12 flowers) per inflorescence, longer sepals and petals (25.0-26.8 × 3.0-5.5 mm vs. ca. 20 × 3-4 mm), white column (vs. pink), and produce fewer fruits (2 vs. 12). Assessing the variation of this broadly distrib uted and rare species is important to characterize it ad equately. Furthermore, careful re-examination of prior works is key to the understanding of this species. We noticed that the scale bar added by Szlachetko et al. (2020) to a reproduction of the type illustration of E. tenuifolium is notoriously inconsistent with the scale bar on the type specimen. Also relevant is the incon sistency between the illustration by Hoehne, which suggests a glabrous lip, and the original illustration ac companying the specimen, which clearly depicts the characteristic villose apical callus.

Acknowledgments

We thank the staff and curators at the CR, JBL, K, USJ, and W. Thanks J. Francisco Morales (TRIN) for providing us with images of Epistephium spe cimens, including the holotype of E. ellipticum. We are grateful to the editors and three anonymous reviewers who greatly improved the manuscript. Thanks to the Ministerio del Ambiente y Energía of Costa Rica (MINAE) and the Sistema Nacional de Áreas de Conservación (SINAC) for providing the scientific permits under which plant materials have been collected. The Vicepresidency of Research of the University of Costa Rica supported this study through re search project 814-C0-049.

Literature cited

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