Maxillaria bicentenaria Collantes & C.Martel, 2021

Maxillaria bicentenaria Collantes & C.Martel View in CoL , sp. nov. ( Figs. 4–6 View FIGURE 4 View FIGURE 5 View FIGURE 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 View FIGURE 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 .