Pabstiella tortuosa N. Gut., E.C.Smidt & Toscano, 2023

Morales, Nicolás Gutiérrez, Brito, A. L. V. Toscano De & Smidt, Eric De Camargo, 2023, Novelties and nomenclatural notes in Pabstiella (Orchidaceae) from the Brazilian Atlantic Rainforest of Bahia and Espírito Santo, Phytotaxa 625 (2), pp. 161-179 : 171-175

Pabstiella tortuosa N. Gut., E.C.Smidt & Toscano , sp. nov. ( Figures 8–10 )

Type: — BRAZIL. Espírito Santo: João Neiva , 700–900 m, collected by Daniel Assis in February 2018, flowered in cultivation at Curitiba, Paraná, 15 March 2023, N. Gutierrez 304 (holotype: UPCB! in spirit) .

Similar to P. pantherina ( Seehawer 1998: 130) Luer & Toscano (2011: 381) , differing by the smaller size, to 11 cm tall, with ramicauls to 5.4 cm long (vs. plants to 15 cm, ramicauls to 8 cm), leaves without a visible central vein (vs leaves with the central vein canaliculate, the underside subcarinate), inflorescence very short, dense, tortuous, to 2 cm tall (vs. inflorescence erect, to 7 cm tall), dorsal sepal with the apical margins recurved (vs. apical margins straight), synsepal arcuate (vs. partially reflexed) and petals with the apical margins entire and thickened along the vein in the external surface (vs. apical margins serrate, without thickenings).

Description:— Plant small, epiphytic, caespitose, up to 11 cm, roots slender, flexuous, to 0.4 mm in diameter. Ramicauls terete, relatively stout, 1.2–5.4 cm long, partially enclosed by 2–3 tubular, ribbed, acute sheaths, with oblique apex. Leaves elliptical to lanceolate, thickly coriaceous, subacute, without a notorious central vein, the apex minutely emarginate with a central mucron, 2.3–4.6 × 0.8–1.2 cm, the base cuneate into a twisted petiole ca. 2.5–4.0 mm. Inflorescences (1–5) per ramicaul, up to 2.0 cm, peduncle reduced, 1.0–3.0 mm long, with 3–6 successive flowers in a very short, tortuous raceme emerging from the apex of the ramicaul, rarely with two simultaneous flowers, the short peduncle with a small bract at the base, floral bracts oblique, acute, ca. 1.7 mm. Pedicel 3.0 mm long, vinaceous or green. Ovary vinaceous or light yellow, terete, shallowly sulcate, more or less arcuate, 1.0– 1.2 mm long. Flower resupinate, descendent, sepals and petals with irregular vinaceous stains in a cream to pale yellow background. Dorsal sepal elliptical-oblong, the basal half convex, the apical margins reflexed, 3-veined, obtuse, 5.5–6.4 × 1.8–2.1 mm. Lateral sepals carinate in the external surface, each 3-veined, connate ca. 2.3–4.0 mm, forming an oblong to obovate, concave, arcuate synsepal, with obtuse apices, 4.3–5.8 × 2.3–2.8 mm unexpanded. Petals unguiculate-spatulate, translucent, 1-veined, slightly asymmetrical, obtuse, the external surface thickened along the vein, 2.7–2.9 × 1.1–1.2 mm. Lip cream with vinaceous stains, 3-lobed, hinged to the column foot, oblong, slightly arcuate, truncate at base, papillose, the lateral lobes erect, rounded, with a pair of low, longitudinal, submarginal calli in the middle third, the apical lobe densely verrucose, rounded, 2.9–3.2 × 1.0 mm unexpanded. Column cream to pale green, more or less vinaceous stained, slightly arcuate, narrowly winged, the apex denticulate, 2.8–3 × 0.8 mm, the anther and stigma ventral, the rostellum orbicular, the foot ca. 0.7 mm long. Anther cream with vinaceous at the apex, triangular, hooded, pollinarium composed of two, yellow, obovate pollinia united by a caudicle. Fruit capsule, not observed.

Distribution and ecology: —the new species has only been found in montane humid forests in the municipalities of Santa Teresa and João Neiva, in Espírito Santo. It grows near the ground and prefers indirect sunlight. The plant that served for the preparation of the type specimen was growing in the same area with other orchid species, such as P. dracula ( Seehawer 1999: 635) Luer & Toscano (2011: 381) , P. armeniaca (Barb. Rodr. 1881: 51) L. Kollmann (2010: 96) and Anathallis rubrolimbata ( Hoehne 1946: 22) Luer & Toscano (2009: 259) . The main blooming period is at the end of summer, from March and April.

Etymology: —referring to the tortuous aspect of the short, intertwined inflorescences ( Figure 9B ).

Aditional material examined (paratype): — BRAZIL. Espírito Santo: without specific locality, flowered in cultivation by Marcos Klingelfus at Curitiba, Paraná, 15 May 2023, N. Gutierrez 308 ( UPCB! in spirit) .

Taxonomic discussion: —Similar to P. pantherina , an endemic species from the mountains of Rio de Janeiro state, they both share the stout ramicauls partially covered by tubular sheaths, coriaceous leaves, few flowered inflorescences not surpassing the leaves, emerging from the apex of the ramicaul, small ovary, flowers resupinate, descendent, maculate with dark purple, with unguiculate-spatulate petals, lip 3-lobed, verrucose, with a pair of submarginal calli. Pabstiella tortuosa is a smaller plant, to 11 cm, ramicauls to 5.4 cm long (vs. 15 cm, ramicauls to 8 cm), leaves without a central notorious vein (vs. central vein canaliculate, the underside subcarinate), short, tortuous inflorescences, to 2 cm, (vs. inflorescences erect, to 7 cm), reduced peduncle, to 3 mm long (vs. peduncle to 10 mm), smaller flowers, dorsal sepal with the apical margins recurved (vs. apical margins straight), synsepal arcuate (vs. partially reflexed) and petals with the apical margins entire, thickened along the vein in the external surface (vs. apical margins serrate, without thickenings).

Also similar to P. tortuosa , but to a lesser degree is P. aurantiaca (Barb.Rodr. 1877: 10) Chiron (2011: 133) ( Figure 11A ), another endemic to southeastern Brazil. Both species share coriaceous, fleshy leaves, short, few-flowered inflorescences emerging from the apex of the ramicaul, flowers descendent, dorsal sepal oblanceolate to oblong, synsepal obovate to oblong and lip oblong, arcuate, verrucose, 3-lobed, with a pair of submarginal, calli. P. tortuosa differs by the elliptical, petiolate leaves (vs. leaves spatulate, attenuate at base), inflorescence with a reduced peduncle, to 3 mm long (vs. peduncle ca. 7 mm), small ovary, to 1.2 mm long, (vs. ovary to 2.7 mm), flowers maculate with dark purple (vs. completely yellow-orange flowers), synsepal with the apical half recurved (vs. apical half straight), petals uncuiculate-spathulate, 1-veined, obtuse (vs. petals oblong, 3-veined, rounded to truncate), lip larger, to 3.2 mm, not fleshy (vs. lip ca. 2 mm long, to the middle thickly fleshy).

The different specimens studied of P. tortuosa exhibit variations in the size of the plants (ranging from 6 to 11 cm tall), length of the ramicauls (6 to 11 cm long), number of flowers per inflorescence (3 to 6) and color of the flowers, the cream-colored background possess irregular vinaceous stains that are variable in size and color intensity, as evidenced in Figures 9 and 10 .

Pabstiella tortuosa possesses a combination of vegetative and reproductive features that is quite rare within the genus. It seems to be related to P. pantherina , P. aurantiaca , P. rhombilabia Chiron & N. Sanson (2011: 134) ( Figure 11B ) and probably P. dracula ( Seehawer 1999: 635) Luer & Toscano (2011: 381) . All share the robust habit, stout ramicauls partially covered by tubular sheaths, thick, coriaceous leaves, with few-flowered inflorescences (up to 6 flowers), emerging from the apex of the ramicaul, successive flowers, occasionally with two simultaneous flowers, ovary more or less arcuate and lip more or less verrucose, with a pair of submarginal calli. Considering that P. rhombilabia was included in the phylogenetic proposal for Pabstiella , it is likely that the aforementioned species are also member of the Ornithoides section. However, molecular evidence is needed to determine whether this group of species forms a distinct lineage within this section.

Figures

FIGURE 8. Illustration of Pabstiella tortuosa. A. Habit. B. Flower and inflorescence. C. Perianth. D. Ovary, column and lip, lateral view. E. Expanded lip. F. Column, ventral view. Illustration by Nicolás Gutiérrez Morales from the holotype.

FIGURE 9. Lankester Composite Dissection Plate of Pabstiella tortuosa. A. Habit. B. Flowers and inflorescence. C. Dissected perianth. D. Ovary, column and lip, lateral view. E. Lip. F. Column, ventral view. G. Anther cap and pollinarium. Photographs by Nicolás Gutiérrez Morales from the paratype.

FIGURE 10. Lankester Composite Dissection Plate of Pabstiella tortuosa, a different color form. A. Habit. B. Flower. C. Dissected perianth. D. Ovary, column and lip, lateral view. E. Lip. F. Column, ventral view. G. Anther cap and pollinarium. Photographs by Nicolás Gutiérrez Morales from Toscano de Brito 3513 (unvouchered).

FIGURE 11. A. Pabstiella aurantiaca. B. Pabstiella rhombilabia. C. Pabstiella crenata. Photos by Nicolás Gutiérrez Morales.