Stelis luz-marinae Rojas-Alv., 2023

Rojas-Alvarado, Gustavo, 2023, A new species of Stelis subgen. Unciferia (Orchidaceae: Pleurothallidinae) from Costa Rica, Phytotaxa 607 (3), pp. 205-212 : 206-211

Stelis luz-marinae Rojas-Alv. , sp. nov. ( Figure 1 )

Type:— COSTA RICA. Alajuela: Río Cuarto, Bosque pluvial premontano, cerca de la plaza de deportes de Pata de Gallo , epífitas sobre palmeras, 10°17’0.69”N 84°12’53.83”W, 1020 m, 1 Jan 2022, G. Rojas-Alvarado 596 (holotype: JBL-spirit!) .

Stelis luz-marinae is similar to S. wercklenana Bogarín & Pupulin in Pupulin et al. (2019: 373) and S. psilantha ( Luer 1998: 95) Pridgeon & M.W.Chase (2001: 266) , but distinguished by its coflorescence as long as the leaves and the lateral lobes of the labellum papillate adaxially vs. coflorescences longer than the leaves and the labellum without papillate lateral lobes.

Description:— Epiphytic, caespitose, small, up to 7–14 cm tall. Rhizome abbreviated among adjacent ramicauls, 1–2 internodes producing roots. Roots 0.5–1.0 mm in diameter, Flexuous. Ramicauls 10.0–20.0 × 1.0 mm, with 2 internodes, the basal one shorter, covered by sheaths. Sheaths papery, brown, acute, the basal one imbricate, the apical one reaching the annulus. Leaves coriaceous, 3.5–10.0 × 0.7–1.0 cm, oblanceolate, cuneate and channaled at the base; apex obtuse, minutely tridentate. Inflorescence with successive erected, secund multi-flowered coflorescences of 5.0–10.0 cm long, generally shorter or as long as the leaf, with a short rachis with simultaneous and successive flowers, 1–5 opened simultaneously, internodes of the rachis 3.0–8.0 mm long. Pseudopeduncle 2.8–6.5 cm long, with 3–4 internodes. The pseudopeduncle and floral bracts acuminate, papery greenish to brownish, 3.0–4.0 × 2.0 mm. Pedicels 3.0–6.0 × 0.5 mm. Ovary glabrous, 2.0–3.0 × 1.0 mm, linear to subclavate, slightly 6-sulcate. Flowers with the sepals yellowish to brownish at the apex and yellowish translucent petals with purple on mid-nerve. Dorsal sepal 8.0–11.0 × 3.5–5.0 mm, ovate-lanceolate, acute, with trichomes along the margins of the adaxial surface, 3-veined, the mid-nerve keeled abaxially; lateral sepals fused to near the apex forming an oblong-ovate, synsepal, 8.0–11.0 × 3.5–5.0 mm, 3-veined, sepal’s apex acute, mid-nerve keeled abaxially, covered by white trichomes along the margins of the adaxial surface. Petals small, elliptic to sub-circular, obtuse to rounded, 2.0– 2.5 mm × 1.5 mm, 1-nerved. Lip narrowly unguiculate, trilobate, 3.5–4.0 mm × 1.0–2.0 (3 mm extended), the base with a pair of parallel rounded small calli forming a glenion like structure; lateral lobes erected below the middle then antrorse, uncinate, acute, parallel with mid lobe, adaxially papillose below the middle; the disc papillose near the base of the lateral lobes, with a pair of submarginal lamellae emerging at the base of the lateral lobes where they are more separate or expanded, then converging to above the middle of the mid lobe gradually fading into the blade with a truncate ending; mid lobe oblong with a rounded to obtuse apex. Column 3.0–4.0 mm × 1.0 mm, whitish to yellowish, purplish basally, curved, winged to the apex; clinandrium elongate, dobly serrate, generally with a pair of teeth; rostelum subcuadrate, truncate; column foot 1.0 mm long. Anther cap 0.75 wide, sub-cuadrate, papillose. Pollinia 2, laterally complanate, 0.3–5.0 mm wide, obovate, caudices 2, flat.

Distribution and ecology: This species had been collected growing as epiphytic in premontane wet and premontane rain forest of the Tilarán mountain range and Central Volcanic range of Costa Rica, at mid elevations from 450 to 1020 m ( Figure 2 ). Some plants were collected on trees of secondary forest and over ornamental palms. No other species of the same group have been collected in the same locality.

Etymology: —The name of the new species honors Luz Marina, mother of the author of this new species.

Additional specimens examined:— COSTA RICA. without collecting data, cultivated by Gerson Villalobos, flowered in cultivation in Jan 2020, G. Rojas-Alvarado 407 (JBL-spirit). Alajuela: Río Cuarto, bosque pluvial premontano, cerca de la plaza de deportes de Pata de Gallo , epífitas sobre palmeras, 10°17’0.69”N 84°12’53.83”O, 1020 m, 1 Jan 2022, G. Rojas-Alvarado 597 (paratype, JBL-spirit); Río Cuarto , bosque pluvial premontano, cerca de la plaza de deportes de Pata de Gallo , epífitas sobre palmeras, 10°17’0.69”N 84°12’53.83”O, 1020 m, 1 Jan 2022, G. Rojas-Alvarado 598 (paratype, JBL-spirit); Río Cuarto , bosque pluvial premontano, camino a Pata de Gallo , epífitas sobre árbol caído a orilla del camio, 10°16’56.28”N 84°12’25.51”O, 970 m, 1 Jan 2022, G. Rojas-Alvarado 601 (paratype, JBL-spirit), Río Cuarto , camino a Laguna Hule, por el antiguo quebrador del ICE, colectada y cultivada por Gerson Villalobos, G. Rojas-Alvarado 594 (JBL-spirit!); San Ramón, Piedades Sur, San Miguel (La Palma), camino a San Bosco, a orillas y dentro de un pequeño bosque secundario. 10º07’18.8”N 84º31’13.1”W, 1062 m. 21 Dec 2010, Karremans 3326 & Contreras (JBL-Spirit!). Heredia: Sarapiquí, La Virgen, Colonia Carvajal, Poza Azul, orillas del Río Poza Azul , 10°19’21.3”N 84°08’19.1”W, 662 m [~ 450 m], bosque muy húmedo tropical transición a premontano, epífitas en bosque secundario, 13 May 2010, Bogarín 7547, Fernández, Karremans, Pupulin & Smith (JBL-spirit!); Sarapiquí, La Virgen, Colonia Carvajal, Poza Azul, orillas del Río Poza Azul , 10°19’21.3”N 84°08’19.1”W, [~ 450 m], bosque muy húmedo tropical transición a premontano, epífitas en bosque secundario, 13 May 2010, Bogarín 7551, Fernández, Karremans, Pupulin & Smith (JBL-spirit!).

Taxonomic discussion: — Stelis luz-marinae is characterized by having a rachis with short internodes (<1 mm) ( Figure 3A ) and coflorescences generally as long as the leaf or shorter, flowers brownish with the adaxial surface of the lateral lobes of the lip papillose ( Figure 4A ). In comparison with the other species of the group, the rachis of S. wagneri ( Schlechter 1921: 141) Pridgeon & M.W.Chase (2001: 267) also has short internodes, but the coflorescence is generally few centimeter (<5 cm) longer than the leaf, however it is distinguished by its dark purple flowers. Juvenil plants of the tiny species S. psilantha may also produces short coflorescences, but it generally continuous elongating with age, surpassing the leaf length and the rachis internodes are generally longer than 1 cm ( Figure 3I ). Even though the application of the name S. segoviensis ( Reichenbach 1855: 223) Pridgeon & M.W.Chase (2001: 266) is quite difficult, the latter is distinguished from Stelis luz-marinae by having a coflorescence longer than the leaf, a clearly appreciated character in the type specimens at C and W herbaria.

Flowers of the new species are yellowish to brownish with the sepals adaxially covered by trichomes. Species with a similar appearance of the flowers are also found in S. werckleana , but with yellowish to greenish striped sepals ( Figure 3F–H ). Within the color variation of S. psilantha , yellowish and brownish flowers are also found, but with glabrous flowers ( Figure 3J–L ). Most of the species of the S. segoviensis group have lanceolate to ovate petals, generally as long as the column, however in S. luz-marinae are generally shorter than the column and elliptic, similar petals are found in S. pompalis Ames (1924: 23) Pridgeon & M.W.Chase (2001: 265) and S. wagneri , but the last species have purple flowers. The elevated and uncinate-antrorse lateral lobes of the lip found in the S. segoviensis group is unique in the genus, and quite similar between the species. Stelis luz-marinae has the adaxial surface of the lateral lobes papillate bellow the middle and the lamellae with a truncate, shortly toothed, or gradually disappearing ending ( Figure 4A ). The adaxially papillose lateral lobes appears to be present in several species of the group, from slightly to density papillose. However, S. luz-marinae is the only having those papillose lateral lobes of the lip and a brownish to yellowish perianth. Also, the way in how the lamellae ends in the middle lobe vary, it may be clearly truncate as in S. pilostoma or S. pompalis , clearly toothed as in S. vinacea Ames (1923: 69) Bogarín in Pupulin et al. (2019: 372). The end of the lamellae is variable in S. luz-marinae and S. wercklena ( Figure 4B–D ), but the lip in the latter has not papillate lateral lobes.

Figures

FIGURE 1. LCDP of Stelis luz-marinae. A. Habit. B. Flower in ¾ view. C. Dissected perianth. D. Column with lip in lateral view. E. Lip in adaxial and ¾ view. F. Column in ventral view. G. Pollinia and anther cap in diferent views. Based on type specimen G. Rojas-Alvarado 596.

FIGURE 2. Distribution map of Stelis luz-marinae in Costa Rica.

FIGURE 3. Comparison of coflorescences and flowers of the similar species. A–D. Stelis luz-marinae (A, D. G. Rojas-Alvarado 596; B. G. Rojas-Alvarado 601; C. G. Rojas-Alvarado 597). E–H. Stelis werckleana (E–F. I. Chinchilla 2394; G. JBL36951; H. D. Bogarín 11320). I–L. Stelis psilantha (I. A. Karremans 8468; J. A. Karremans 8325; K. A. Karremans 8314; L. G. Rojas-Alvarado 508). Scale bar of the flowers=5 mm (applies for the flowers’ photos), scale bar of the coflorescences=2.5 cm (applies for the coflorescences’ photos).

FIGURE 4. Different view of the lips of the similar species. A. Stelis luz-marinae (G. Rojas-Alvarado 596). B–D. Stelis werckleana (B. D. Bogarín 11320; C. JBL36951; D. L. Álvarez 771). E–G. Stelis psilantha (E. A. Karremans 8326; F. G. Rojas-Alvarado 508; G. A. Karremans 8314). Scale bar=1 mm.Arrow indicate the end of the lammellae.