Maxillaria bicentenaria Collantes & C.Martel, 2021

Martel, Carlos, Egoavil, Luis, Ocupa, Luis, Tello, Juan Andre, Patrón, Federico Rizo, Laura, César, León, Marco & Collantes, Benjamín, 2021, An homage to Peru’s bicentenary: Maxillaria bicentenaria (Orchidaceae), a new species previously misidentified as M. pyhalae, Phytotaxa 518 (2), pp. 87-99 : 91-95

Maxillaria bicentenaria Collantes & C.Martel , sp. nov. ( Figs. 4–6 )

Similar to Maxillaria pyhalae D.E. Benn. & Christenson , but differing in the elliptic to sub-elliptic labellum, the distal half of the labellum irregularly plicate, the flattened and transversally sub-trapezoidal labellar callus, the campanulate to sub-campanulate protuberance at the labellum apex centre, and the conspicuous carina with a sharp edge towards the top of the anther.

Type:— PERU. Pasco: Prov. of Oxapampa, conservation area of Bosque de Sho’llet, Rincón Chacos , 2400 m, 16 March 2021, Martel et al. 99 (holotype, USM) .

Plant up to 50 cm tall (including the inflorescence), terrestrial, caespitose. Roots slender, born from the rhizome at the base of the pseudobulb. Rhizome stout, 5–8 × 0.5 cm, covered by scarious bracts. Pseudobulb 6.5 × 1.2 cm, narrowly ovoid, laterally flattened, bevelled on one side, a laterally flattened segment of 1.9 × 0.6–0.7 cm formed by a narrowing apex; basal bracts 8 × 1 cm, conduplicate at the base; foliaceous bracts 14 cm long. Leaf 37 × 4 cm, unifoliate; petiole 7 × 0.5 cm long; blade 6 × 1.2 cm, loriform, acuminate apex. Inflorescence up to 43 cm long, basal, terete, slender scape covered by nine bracts, internode apical of 3 mm in diameter; bracts 9, amplexicaul, largely acuminate; floral bract widely ovate, cucullate and carinate on the back, acute, unguiculate base of 5 × 10 mm. Flower non-resupinate, red and white, 3–4 cm long, facing downwards. Ovary 37–42 × 3.0– 3.6 cm, dark brown to purple, arcuate. Sepals with a longitudinal white stripe in the middle, flanked by two red stripes on the sides; dorsal sepal 3.5–4.1 × 1.3–1.4 cm, ovate-oblong, acute and mucronate apex, reflexed, margin entire, sub-sinuate towards the apex, 10-nerved; lateral sepals 3.4–3.8 × 2.0 cm, falcate, reflexed, acute and mucronate apex, irregularly entire margin and sub-sinuate towards the apex, 12–14-nerved. Petals 3.2–3.4 × 1.2 cm, sub-falcate, with a longitudinal white stripe in the middle, flanked by two red stripes on the sides, acute apex, irregularly entire margin at the base, irregularly erose-undulate margin along the last 2/3, 10–11-nerved. Labellum 2.0–2.1 × 1.4 cm, elliptic to sub-elliptic, 15–16-nerved, adaxial surface covered by abundant spherical and sub-spherical yellow pseudopollen granules forming filamentous plush clumps towards the disk base, a transversal sub-trapezoidal short callus of 5 × 2 mm in the middle on the adaxial surface, a 6 mm long arc on the abaxial surface; basal half with entire and dark red to marron stripes at the margins; distal half irregularly plicate towards the apex, margins irregularly denticulate, dark garnet with irregular reddish spots; apex transversally revolute of 6–8 mm long, mustard with dark red spots, margin revolute of 8–9 mm long; apex centre a campanulate to sub-campanulate protuberance of 4 mm long, with a fine and irregular dorsal groove, covered by pseudopollen, revolute margins dorsally as open lips. Column 10 × 5.5 cm, slightly arcuate and sub-clavate, semi-terete, slightly concave ventral surface, surface with minute dactylar papillae, white and ventrally yellowish cream with irregular dark red dots; clinandrium short, with minuscule dactylar appendices of variable size; column foot 16–18 × 5 mm, arcuate. Anther 5.2–6 × 4.5 mm, sub-spherical, dorsoventrally slightly flattened, slightly flattened towards the top and conspicuously carinate at the top with a sharp edge and decorated with various minuscule papillae, the carina projects backwards, dark cream. Pollinarium 4.9 × 2.6 mm, 4-pollinia; viscidium saddle- or inverted V-shaped; pollinium complanate, oblong-obovoid to claviform, flat convex to convex-concave, larger pair 3.1 × 1.2 mm, smaller pair 2.2 × 1 mm. Fruit not recorded.

Phenology: —This species flowers between December and April.

Distribution, habitat, and ecology: — Maxillaria bicentenaria is known from four localities in the dry montane forests of the OAYBR in central Peru ( Fig. 3 ). Plants of M. bicentenaria grow in semi-dry montane forests, exposed or shaded undergrowth on rocks or soil associated with ferns and other orchids.

Additional specimens examined (paratypes): — PERU. Pasco: Prov. of Oxapampa, Cordillera Yanachaga, 14 km E of main Oxapampa-Villa Rica road, lumber road at top of Cordillera , 2450 m, 2 March 1982, Gentry & Smith 35980 ( F, photo); 12 km SE of town, road over shoulder of Cero Pajonal to Villa Rica, between 5 February and 2 April 1997, Weigend & Dostert 9 7/60 ( F, photo); 2363 m, 23 February 2008, Vásquez et al. 33583 ( MO, photo); San Alberto basin, 4 February 2021, Rizo Patrón 91 ( USM) ; Cerro Pajonal, road from Oxapampa to Villa Rica , 2300 m, 11 March 2021, Martel et al. 98 ( USM) ; Rincon Chacos , 2380 m, 12 March 2021, Martel et al. 100 ( USM) .

Conservation Status: — Maxillaria bicentenaria is known from several populations restricted to the Province of Oxapampa. The species is locally abundant and dozens of individuals can be found in a patch. We calculated that the observed populations accounted for less than 1000 individuals. Therefore, following the criteria of the IUCN Red List ( IUCN 2019), the species can be listed as Endangered (EN), based on criterion D.

Etymology: —The name of the new species is an homage to the 200th anniversary of the Peruvian declaration of independence, which occurred on July 28 th, 1821.

Comments: —A specimen of M. bicentenaria had been collected by Gentry and Smith (35980, F) in 1982. A duplicate deposited at USM was later determined as M. pyhalae by Christenson (2006). Other specimens from the type and nearby localities were determined as M. aff. pyhalae (Weigend & Dostert 97/60, F) and M. pyhalae (Vásquez et al. 33583, MO). Nevertheless, those specimens are here identified as M. bicentenaria instead. Images of M. bicentenaria have been previously published in local plant guides (i.e. Vásquez et al. 2005, CTB/PRODERN 2015) as M. pyhalae .

Figures

FIGURE 3. Geographical locations of Maxillaria bicentenaria (squares) and M. pyhalae (triangles) in Peru. Names in capital letters indicate political departments and names associated to red dots indicate provincial capitals. Colour scale indicates elevation.

FIGURE 4. Maxillaria bicentenaria. A. Habit. B. Pseudobulb, side view. C. Flower, frontal view. D. Dissected flower with extended perianth and details of the sepal apex. E. Labellum and column, lateral view with details of the anther margin. F. Labella, frontal view with detail of the abaxial side of the extended apex. G. Column, ventral and lateral view with details of the margins. H. Anther and pollinarium, ventral and dorsal views. Note the flower is non-resupinate and it is shown as resupinate in D for graphical purposes only. Drawn from C. Martel et al. 99–100 (USM) by B. Collantes (personal plate nº 52).

FIGURE 5. Maxillaria bicentenaria.A. Habit. B. Flower, lateral view. C. Dissected perianth, frontal view with detail of the abaxial side of the dorsal sepal apex. D. Labellum and column, lateral view. E. Column, lateral view. F. Anther, frontal and dorsal views. G. Pollinarium, frontal and ventral views. Note the flower is non-resupinate and it is shown as resupinate in B and C for graphical purposes only. Prepared by L. Ocupa.

FIGURE 6. Maxillaria bicentenaria. A. Habit. B. Flower, frontal view. Photographs by F. Rizo Patrón (A) and C. Martel (B).