Octomeria imigiae T.F. Santos, Toscano & E.C. Smidt, 2022

Santos, Thiago Faria Dos, Brito, Antonio Luiz Vieira Toscano De & Smidt, Eric De Camargo, 2022, A new Octomeria (Orchidaceae: Pleurothallidinae) and nomenclatural notes for related Southern Brazilian species, Phytotaxa 572 (3), pp. 275-282 : 276

Octomeria imigiae T.F. Santos, Toscano & E.C. Smidt , sp. nov. ( Figures 1–2 ).

Type — BRAZIL. Santa Catarina: São Bento do Sul, Fazenda Antonio Czieczeck , 18 August 2018, D.C. Imig 624 (holotype: UPCB 0052221 !) .

Differs from other species from the genus due to the combination of the following characteristics: reptant growth habit; leaves always longer than the ramicauls, cylindrical to sub-cylindrical when mature, flat to conduplicate when young, with usually a slightly arched and acute apex; floral parts are small, not exceeding 5 mm; sepals and petals are elliptical to lanceolate, with an obtuse apex; lip trilobed, with inconspicuous lateral lobes, and sub-rhombic median lobe with truncate apex.

Description:— Plant 25–62 mm long, epiphytic. Roots cylindrical, flexuose. Rhizome 3 mm thick, 2–10 mm long between ramicauls, reptant, stout. Ramicauls 10–21 mm long, erect, cylindrical, enclosed by 1–2 overlapping tubular pale sheaths. Leaves 20–49 × 1.3–1.6 mm, arched, leathery, flat to conduplicate when young, cylindrical when mature, base cuneate, apex acute. Inflorescence 1–2 flowers, in fascicle. Flowers pedicelled, pedicel 0.4–0.5 mm, ovary 0.4 mm long. Sepals yellow, glabrous, free, 3-veined, the dorsal sepal 3.0–4.5 × 2–2.4 mm, elliptical to elliptic-lanceolate, apex obtuse to slightly acute; the lateral sepals 3.5–4.0 × 1.8–2 mm, elliptic-lanceolate, apex obtuse to slightly acute. Petals yellow, glabrous, 1-veined, 3.0–3.7 × 1.3–1.5 mm, elliptical to lanceolate, apex obtuse to slightly acute. Lip yellow, glabrous, trilobed; 2.1–3.0 × 1.4–1.6 mm, margin entire, base truncate, the disk smooth, concave between a pair of longitudinal, slightly parallel calli which extend from the lateral lobes to approximately half of the lip; lateral lobes inconspicuous, rounded, margin entire; median lobe sub-rhombic, apex truncate. Column yellow, erect to slightly arched; 1.0–1.1 × 0.3–0.5 mm, cylindrical, wings rounded.

Distribution and ecology: — Octomeria imigiae seems to be endemic to the south of Brazil. So far it has been recorded for the municipality of Piraquara, in the state of Paraná, and for the municipality of São Bento do Sul, in the state of Santa Catarina, flowering from August to September. In Paraná, it grows in an ecotone between Mixed and Dense Ombrophilous Forest, at an elevation of c. 900m. In Santa Catarina, it grows in Mixed Ombrophilous Forest as an epiphyte on branches of Ocotea spp . at an elevation of c. 850m.

Etymology: —In honour of Dr Daniela Cristina Imig , a botanist who found the species in the field.

Additional specimens examined (paratype):— BRAZIL. Paraná: Piraquara, Campininha , 4 September 1949, Gerdt G. Hatschbach 1536 (MBM 50033!, SP 55378!) .

Taxonomic Discussion: — Hoehne (1950) misidentified O. imigiae as O. riograndensis . Pabst & Dungs (1975:371) followed Hoehne (1950) and illustrated O. imigiae wrongly named as O. riograndensis . Octomeria imigiae is similar to other species native to the Atlantic Rainforest in south Brazil, such as O. chamaeleptotes Reichenbach (1849: 817) , O. cucullata Porto and Brade (1937: 135) , O. gracilis Loddiges ex Lindley (1838: 36) , O. lichenicola Barbosa Rodrigues (1882: 112) , O. linearifolia Barbosa Rodrigues (1882: 106) , O. ochroleuca Barbosa Rodrigues (1882: 31) , O. octomeriantha ( Hoehne 1936: 24) Pabst (1972: 180) , O. rohrii Pabst (1951: 220) and O. rubrifolia Barbosa Rodrigues (1882: 31) , which can be recognized by the following key.

Figures

FIGURE 1. “Lankester Composite Dissection Plate (LCDP)” of Octomeria imigiae by T.F. Santos; based on the holotype specimen. A. Habit. B. Flower. C. Perianth dissected. D. Column with the lip. E. Front view of the column. F. Pollinia and anther cap.

FIGURE 2. Illustration of Octomeria imigiae by L.K.R. Hinoshita; based on the holotype specimen. A. Habit. B. Frontal view of the flower. C. Dissected flower. D. Lateral view of the flower.