Introduction

There are currently four recognized genera in the Neotropical tribe Sobralieae: Elleanthus C. Presl, Epilyna Schltr., Sertifera Lindl. & Rchb.f, and Sobralia Ruiz & Pav. (including Brasolia (Rchb.f.) Baranow, Dudek & Szlach.) (^{Neubig et al. 2011}, ^{Chase et al. 2015}, ^{Baranow, Dudek & Szlachetko 2017}).

Orchids of the genus Sertifera have relatively small flowers of bright colors, which resemble the flowers of Elleanthus. Vegetatively, Sertifera, like Elleanthus and Sobralia, are caespitose plants with slender, elongate cane-like stems and plicate leaves. However, Sertifera is easily distinguished from the other genera of the tribe by having leaf sheaths with tubercles, axillary and secund or subcapitate inflorescences, and flattened peduncle.

Lindley and ^{Reichenbach (Reichenbach 1877}) described Sertifera with two species: S. purpurea Lindl. & Rchb.f. from Ecuador (with “lateral corymbose” inflorescence) and S. virgata Rchb.f. from Peru (with terminal racemes inflorescence). However, the latter was transferred by ^{Schweinfurth (1938}) to Elleanthus. The second species of Sertifera, from Ecuador, was described by ^{Kraenzlin (1899}) but hiding under the name of Diothonea lehmanniana Kraenzl. (transferred to Sertifera by ^{Garay in 1978}). ^{Schlechter (1920}, 1924) then described three species from Colombia: Sertifera colombiana Schltr., S. major Schltr. and S. parviflora Schltr. Subsequently, ^{Williams (1939}) and ^{Schweinfurth (1946)} described two more species from the same country: S. grandifolia L.O.Williams and S. aurantiaca C.Schweinf., respectively. Recently, another three species have been proposed for Colombia: S. gracilis Rchb.f. ex Szlach. & Baranow, S. risaraldana Szlach. & Baranow and S. albiflora Szlach., Kolan. &. MedinaTr., (^{Szlachetko & Baranow 2014}, ^{Szlachetko, Kolanowska & Medina Trejo 2014}). Thereby, at the moment ten species are referable to Sertifera.

Sertifera has been referred as a genus restricted to the northern Andes, species have been reported from Ecuador, Colombia, and Venezuela between 1,000 and 3,600 m of elevation (^{Schlechter 1924}, ^{Szlachetko & Baranow 2014}).

Recent field work in the North of Peru revealed the presence of populations of S. purpurea; which represent the first record for this country. Previously, during a Rapid Assessment in The Cordillera del Cóndor, next to the Ecuadorian border, two specimens (one sterile) were collected and identified as Sertifera sp. (^{Schulenberg & Awbrey 1997}). Those specimens are housed at MOL and were examined for this present study. Here, we formally record the genus Sertifera for Peru and provide a description of Sertifera purpurea based on the Peruvian specimens.

Figure 1 Sertifera purpurea. A. Plant in its natural habitat showing a branched stem. B. Verrucose leaf sheaths. Photographs by J. Edquén. 

Taxonomic treatment

Sertifera purpurea Lindl. & Rchb.f., Linnaea 41: 64. 1877.

TYPES: Ecuador, [Andes Quitensis], Tungurahua, Spruce 5394 (syntype: W-76627, photo seen, designated as lectotype by ^{Garay, 1978}). Ecuador, [Quito], Jameson s.n. (syntype W-76625, photo seen). Ecuador, [Valley of Lloa, 1857], Jameson s.n. (syntype: K-501912, photo seen, (mixed), photo at AMES). Ecuador, [from the forest on the western slope of the Andes, 1854] Jameson s.n. (syntype: K-501912, photo seen, (mixed), photo at AMES).

Synonym: Sertifera lehmanniana (Kraenzl.) Garay, Fl. ^{Ecuador 9}: 135. 1978. Diothonea lehmanniana Kraenzl., Bot. Jahrb. Syst. 26: 489. 1899. TYPE: Ecuador. Pichincha: Western declivity of Cerro Corazón, near Canchacoto on Río Pilatón, [2000 m, Jan 1881], Lehmann 126 (G-422011, photo seen, lectotype, designated by Garay, 1978; isolectotype G[x2], photos seen, HUH-82476 [flower at AMES ex G], photo seen).

Plant terrestrial, up to 1 m tall. Stem cane-like, erect to slightly arcuate, enclosed by reddish brown verrucose tubular leaf sheaths, unbranched (rarely branched), leafy above (Fig. 1A, B). Leaves somewhat coriaceous, blades ovate-lanceolate to elliptic- lanceolate, acuminate, plicate, margins minutely erose, sessile on tubular sheaths, 3.1-7.7 × 0.7-1.8 cm. Inflorescence axillary, arcuate, subcapitate, shorter than the subtending leaf; peduncle flattened, 1.0-2.5 cm long; rachis 0.7-1.0 cm long, 6 to 8 flowers. Floral bracts linear-lanceolate, acute to acuminate, green turning blackish purple, 2.0-4.5 mm long (decreasing in size towards the apex). Flowers globose, sepals and petals pink to purplish, lip and tip of petals white (Fig. 2A); ovary and pedicel green to red-violet. Dorsal sepal elliptic, acute to obtuse, minutely mucronate at apex, 3-nerved, 5.5-6.5 × 3-4 mm. Lateral sepals slightly connate at base, oblique, elliptic, acute, mucronate, dorsally carinate, 3-nerved, 6-7 × 3-4 mm.

Figure 2 Sertifera purpurea A. Inflorescence B. Fruits, C. Habitat. Photographs A by J. Edquén; B, C by M. Acuña-Tarazona. 

Petals ovate-elliptic to subrhombic, obtuse, somewhat undulate towards the apex, 1-nerved (sometimes with 1 or 2 short lateral nerves), 5-7 × 3.0-3.5 mm. Lip enfolding the column, basally saccate, conduplicate, flattened laterally, seen from the side subquadrate- obovate, when expanded transversely elliptic, base of the lip thickened, with a small callus, disc provided with a transverse, plate-like ridge which holds the two sides together, the upper margins involute and irregularly erose to shortly lacerate, 5.5-7.0 mm long. Column slender, slightly curved upward, auriculate at apex, 3.5-5.0 mm long. Anther reniform, 1 mm long. Stigma bilobed. Ovary cylindric, curved, glabrous, 7-14 mm long. Fruit narrowly ellipsoid, 13-17 × 2-5 mm (Figs. 2B, 3).

Figure 3 Sertifera purpurea. A. Habit. B. Flower. C. Dissected perianth. D. Lip. lateral view. E. Lip, ventral view, F. Lip, longitudinal section. G. Column (from two different flowers). H. Anther cap. Drawing by D. Trujillo based on M. Acuña 1803 (USM). 

Specimen examined: Peru. [Amazonas, Prov. Condorcanqui], Cordillera del Cóndor, [July -August 1994] M. Cavero 1636 (MOL). San Martín, Prov. Rioja, Distrito Pardo Miguel Naranjos, Bosque de Protección Alto Mayo, 2500 m, 13 April 2017, M. Acuña et al. 1803 (USM). Same locality, 3053 m, 23 May 2017, M. Acuña et al. 1969 (USM).

Other specimens: Peru [Amazonas, Prov. Condorcanqui], Cordillera del Cóndor, [July -August 1994], M. Cavero 1627 (MOL [sterile]).

Distribution: Venezuela, Colombia, Ecuador, and Peru. In Peru, it is known in the Departments of Amazonas and San Martín, between 2,150 and 3,053 m elevation (Fig. 4).

Habitat and ecology: Plants of this species were found growing in shrub vegetation with small trees up to 5 m tall, dominated by Podocarpus oleifolius D.Don ex Lamb., Clusia sp., Weinmannia sp., Miconia sp., and Myrcia sp., and open areas with herbs and small shrubs (Fig. 2C). Individuals with flowers and fruits were recorded in April, May and October.

Sertifera purpurea and S. lehmanniana were described based on plants from the north-central Andes of the Ecuador. The type specimens of S. purpurea were collected in the Province of Tungurahua (Spruce 5394) and the Province of Pichincha: Quito (Jameson s.n.) and in the Valley of Lloa (Jameson s.n.). The type specimen of S. lehmanniana was collected in the Province of Pichincha: west of Cerro Corazon (south of Quito), near Canchacoto (Lehman 126). Both species display similar morphological features. Based on examination of the herbarium specimens (digital images) and a dissected flower of the lectotype of S. lehmanniana (microscope slide prepared by Garay, HUH-82476), the feature that distinguishes S. lehmanniana from S. purpurea is that the first displays ovate-oblong to ovate-ligulate petals (vs. ovate-elliptic to subrhombic). ^{Dunsterville and Garay (1966}) considered that they both represent the same species and placed S. lehmanniana as synonym of S. purpurea; we agree with that assessment.

Figure 4 Distribution map of Sertifera purpurea (black circles) in Peru. 

Sertifera colombiana is also similar to S. purpurea (^{Schlechter 1920}, ^{Mansfeld 1929}, plate 13, nr. 46); however, additional research is necessary to state whether they are the same species.