Pabstiella shirafuchii N.Gut., E.C.Smidt & Toscano, 2025

Morales, Nicolás Gutiérrez, Brito, A. L. V. Toscano De, Restrepo, Eugenio, Gil-Amaya, Karen & Smidt, Eric De Camargo, 2025, Contributions to the knowledge of Pabstiella (Orchidaceae: Pleurothallidinae) from Brazil: A new species, new synonyms and taxonomic notes, Phytotaxa 696 (2), pp. 145-157 : 146-151

Pabstiella shirafuchii N.Gut., E.C.Smidt & Toscano sp. nov.

( Figures 1 , 2 , 3 , 4A ).

Type: — BRAZIL. São Paulo: Miracatu, Santa Rita do Ribeira , 648 m, September 2014, collected by Mário Shirafuchi, flowered in June 2023, N. Gutierrez 293 (holotype: UPCB 110510 in spirit).

Similar to Pabstiella punctata ( Barbosa Rodrigues 1881: 52) Luer & Toscano (2011: 381) , but smaller, up to 6.5 cm tall (vs. 9.5 cm), with shorter leaves, to 5 cm long (vs. to 7 cm). The sepals of the new species are yellow-vinaceous, finely vinaceous spotted (vs. yellow with dark purple stains), the petals are vinaceous, with a conspicuous, external carina (vs. petals yellow with dark purple spots, subcarinate). The lip is distinguishable by its triangular and papillose apical lobe (vs. lip with a rounded, verrucose apical lobe).

Description:— Plant small, caespitose, up to 6.5 cm, roots slender, 0.5–0.7 mm in diameter. Ramicauls slender, 1.7–4.0 mm long, enclosed by three tubular, membranaceous, ribbed sheaths, the apex oblique, acute, the middle sheath partially covering the ramicaul. Leaves narrowly lanceolate, coriaceous, the apex minutely emarginate with the mid vein extending beneath and ending in a short, acuminate mucro, acute, 2.0–5.0 × 0.4–0.6 cm, the base cuneate into a petiole 2.0–4.0 mm long. Inflorescence emerging from the apex of the ramicaul, embraced at base by a minute spathe of less than 1 mm long, with up to 4 successive coflorescences, each coflorescensce suberect, with 3–5 successive flowers, up to 3.2 cm; pseudopeduncle 1.5–2.0 cm long, with two internodes, each with a tubular, acute bract, 2 mm long, floral bracts tubular, acute, ca. 1.2 mm long. Pedicel 1.0– 1.5 mm long. Ovary 0.8–1.3 mm long. Flowers non resupinate. Sepals yellow, vinaceous along the longitudinal middle, finely spotted in vinaceous; dorsal sepal oblong-obovate, slightly concave, subcarinate, 3-veined, the apical margins slightly revolute, acute, 5.0 × 2.0– 2.5 mm. Lateral sepals carinate externally along the midvein, each 3-veined, connate ca. 3.8 mm into a bifid, oblong, concave synsepal with acute apices, 4.4 × 3.0– 3.1 mm. Petals vinaceous, unguiculate, the apical half rhomboid, 1-veined, slightly asymmetrical, the external surface bullate, 1-carinate, the apical margins minutely erose, acute, 2.5–3.3 × 1.0 mm. Lip completely vinaceous or suffused with cream near the base, oblong-lanceolate, 3-lobed, hinged to the column foot, truncate at base with a pair of minute lobules at the corners, the lateral lobes in the middle third, erect, rounded, with a pair of longitudinal, verrucose calli, the apical lobe triangular, papillose, 2.8–3.2 × 1.5–2.0 mm expanded. Column almost completely vinaceous or yellow-green with vinaceous margins, slightly arcuate, narrowly winged, the apex tridentate, 2.3–2.7 mm long, the foot granulose, ca. 0.6 mm long. Anther gibbous, white suffused with magenta; pollinia obovate, laterally compressed and united by a caudicle.

Distribution and ecology: —The new species has been recorded in two states of southeastern Brazil: São Paulo and Rio de Janeiro, within the Serra do Mar range, at altitudes of 650–1500 m. An older collection from Bom Jardim de Minas, Minas Gerais, deposited at HB (19515), may represent the same species. Unfortunately, we were unable to confirm this identification, as the new species was only recognized after our visit to this herbarium, and at that time, the available specimen photos were insufficient. Nonetheless, this suggests that the species distribution likely extends to the Serra da Mantiqueira.

The cultivated plant used to prepare the type specimen was collected from medium-height hygrophilous forests, commonly referred to as mata de brejo in São Paulo state, at an altitude of 650 m. According to Miller et al. (2006), the species was found inhabiting Ombrophilous forests, growing on shaded high branches, at an altitude of 1500 m. The authors also report a blooming period from March to April and note the long-lasting flowers of this species, which can persist for 3–4 weeks.

Etymology: —Dedicated to Mário Shirafuchi who collected the plant that served for the preparation of the holotype specimen.

Additional material examined (paratypes): — BRAZIL. Rio de Janeiro: Serra de Macaé de Cima , 650-750 m, 2006, Seehawer s.n. ( RB 432203 ) ( Figure 3 ) ; Illustration 1157 (prancha IX), by Miller et al. (2006: 535) in Serra dos Órgãos , sua história e suas orquídeas, as Pleurothallis cordilabia Pabst (1972: 267) .

Taxonomic Discussion: —The new species is similar to P. punctata ( Figure 4B ) and P. fluminensis ( Pabst 1973: 363) Luer (2007: 119) ( Figure 4C ). All three are small to medium-sized orchids characterized by lanceolate to linear leaves, short inflorescences, and a few non-resupinate flowers. As observed in many other species of the P. section Brachystachyae N.Gut, Toscano & E.C.Smidt , the flowers are borne on a minute pedicel, and their floral morphology is notably similar.

Compared to P. punctata , P. shirafuchii is a smaller plant, up to 6.5 cm tall (vs. 9.5 cm), with shorter leaves, up to 5 cm long (vs. leaves up to 7 cm). The inflorescences, with several coflorescences bearing 4–5 non-resupinate flowers, are very similar in both species. However, in P. shirafuchii , the pseudopeduncle is somewhat longer, up to 3.2 cm (vs. pseudopeduncle up to 2.9 cm). The flowers of P. shirafuchii are smaller, with sepals vinaceous in the center, yellow towards the margins, and more or less spotted with vinaceous (vs. larger flowers, with sepals commonly yellow marked with dark purple stains). The dorsal sepal of P. shirafuchii is oblong-obovate, up to 5 mm long and 2.5 mm wide (vs. dorsal sepal oblong, up to 7 mm long and 2 mm wide). Similarly, the synsepal of P. shirafuchii is shorter, 4.4 mm long (vs. synsepal up to 7 mm).

The petals are similar in shape and bullate externally in both species, in P. shirafuchii they are vinaceous with a conspicuous central carina (vs. petals yellow with purple spots, subcarinate). The lip of P. shirafuchii varies from completely vinaceous to vinaceous-cream and is distinguishable by its triangular and papillose apical lobe (vs. lip dark purple with pale yellow, with a rounded, verrucose apical lobe). The anther is similar in morphology and color in both species: gibbous, white ventrally but completely dark purple on the dorsal side.

The new species is also similar to P. fluminensis , which presents a similar overall size, flower shape and color pattern. P. shirafuchii can be easily distinguished by its narrowly lanceolate leaves (vs. linear leaves), inflorescences with a considerably longer pseudopeduncle, up to 3.2 cm (vs. up to 3 mm), and co-inflorescences bearing 3–5 flowers (vs. 2–3 flowers). In P. shirafuchii the sepals are yellow, vinaceous along the longitudinal middle and finely spotted (vs. entirely yellow-green with dark purple stains), the petals are vinaceous, externally bullate and 1-carinate (vs. pale yellow-green, vinaceous stained, smooth externally), and the lip has an apical lobe triangular, papillose, with inconspicuous calli (vs. apical lobe verrucose, rounded, the calli conspicious).

Miller et al. (2006) discussed this species in the book Serra dos Órgãos , sua história e suas orquídeas, identifying it as Pleurothallis cordilabia Pabst , formerly Pabstiella cordilabia (Pabst) Luer (2007: 119) . In this work, the authors provided a color illustration and a detailed description, including information about the habitat where the species occurs. This confusion between species is understandable due to the similar size and shape of the vegetative parts of P. shirafuchii and P. cordilabia . Additionally, the shape of the petals and lip, the latter with broad lateral lobes and cordate when expanded, is similar in both species. Nevertheless, P. cordilabia (see Toscano de Brito & Luer 2016) is restricted to the state of Espírito Santo. It has considerably longer inflorescences, up to 6.5 cm (vs. 3.2 cm in P. shirafuchii ), pedicels 2–5 mm long (vs. pedicels 1.0– 1.5 mm), externally verrucose petals (vs. externally carinate petals), and a rounded, verrucose apical lobe of the lip (vs. a triangular, papillose apical lobe in P. shirafuchii ).

Figures

FIGURE 1. Illustration of Pabstiella shirafuchii. A. Habit. B. Flower. C. Dissected perianth, with both surfaces of a petal. D. Ovary, column and lip, lateral view. E. Expanded lip. F. Lip ¾ view. Illustration by N. Gutiérrez Morales, based on the holotype.

FIGURE 2. Lankester Composite Dissection Plate of Pabstiella shirafuchii. A. Habit. B. Flower. C. Dissected perianth. D. Ovary, column and lip, lateral view. E. Lip. F. Anther cap and pollinarium. Photographs by N. Gutiérrez Morales, from the holotype.

FIGURE 3. Paratype of Pabstiella shirafuchii deposited at RB in Rio de Janeiro. Photo courtesy of RB herbarium.

FIGURE 4. Pabstiella shirafuchii and similar morphological species. A. Pabstiella shirafuchii. B. Pabstiella punctata based on N. Gutierrez 301 (UPCB 110432). C. Pabstiella fluminensis based on N. Gutierrez 350 (UPCB 110461). Photographs by N. Gutiérrez Morales.