A new species of Heliconia (Heliconiaceae) with pendent inflorescence, from Chucantí Private Nature Reserve, eastern Panama

Abstract Heliconia berguidoi (Heliconiaceae), a new species from premontane forest of eastern Panama, is described, illustrated and its conservation status evaluated. Heliconia berguidoi bears pink flowers, an uncommon color in this group. It differs from the Colombian species Heliconia rhodantha and Heliconia sanctae-theresae, the most similar taxa, by the combination of a petiole glabrous except for the woolly base, a very long peduncle, the perianth pubescent at the apex and staminode with cuspidate apex. Heliconia berguidoi is also similar to Heliconia pogonantha in all four of its varieties and to Heliconia ramonensis in two of its four varieties, but differs by a combination of the long peduncle, pink flowers and staminode with cuspidate apex. Fifty-six Heliconia species have been found in Panama, eighteen of them endemic.


Introduction
Heliconia L. is the only genus in the plant family Heliconiaceae, which is included in the order Zingiberales (Berry andKress 1991, APG IV 2016). This family is native to tropical America (Caribbean islands, Mexico, Central America and South America) with a small number of species in the Old World tropics, distributed from Samoa, westward to the central Indonesian island of Sulawesi (Kress 1984, Kress 1990b, Berry and Kress 1991. Heliconia has been formally and informally divided into five subgenera: Taeniostrobus (Kuntze) Griggs, Heliconia, Stenochlamys Baker, Griggsia L. Andersson and Heliconiopsis (Miq.) Kress (Andersson 1985(Andersson , 1992Kress 1984Kress , 1990a.
The total number of Heliconia species is still unclear, although in a recent account Ferreira de Castro et al. (2007) registered 176 for the Neotropical region and 6 in the Pacific islands, for a total of 182 species distributed in five (5) subgenera and twentythree (23) sections. Kress and Betancur (2009) recently described one more new species from Colombia which makes a total of 183 recognized species. In Panama, 55 Heliconia species and infraspecific taxa have been reported and the country has the third largest number of endemics (17), after Colombia (36) and Ecuador (21) (Kress 2003, Correa et al. 2004, Ferreira de Castro et al. 2007, TROPICOS 2016 Chucantí Private Nature Reserve (404 hectares) is located on the border of Panama and Darién Provinces, on the eastern edge of Serranía de Majé, an isolated mountain range about 60 km long. It is 30 km south of the continental divide across the valley of the Bayano River and 15 km inland from the Pacific (Figure 1). The range rises gradually towards the east, with the highest point, Cerro Chucantí (1,439 m) at the eastern end (BirdLife International 2016). The reserve, which extends from around 800 m to the highest summit, harbors premontane and lower montane rain forests (Holdridge et al. 1971). According to the ecoregion classification system (WWF 2016), Chucantí is part of the Eastern Panamanian montane forests ecoregion. It has been designated an Important Bird Area (IBA) in Danger (Angehr 2003), as the extensive loss of forests due to cattle ranching activities is putting in peril the existence of several endemic bird species. As part of a floristic inventory of the region carried out by two of the authors (Flores and Ibáñez, unpublished), ca. 250 species have been identified from more than 500 collections. At least 6 of them have been recognized as species new to science (Ortiz et al. 2016;Flores et al., submitted;Valdespino et al. in prep.), including the new Heliconia described here. Endemic species of fauna have also been recently described from the area (Batista et al. 2014, Bezark et al. 2013, Miranda and Bermúdez 2010. All of these novelties highlight the importance for conservation of this undercollected region of Panama. Discovering, describing and conserving biodiversity is the purpose of the Asociación Adopta el Bosque Panamá, owner of the Chucantí Private Nature reserve.

Materials and methods
One live plant of H. berguidoi was collected in Chucantí Private Nature Reserve (2006) and was grown at Finca las Chichicas (Chiriquí Province). Ten years later, a specimen from the original plant was photographed, studied under cultivation, collected, illustrated and deposited at the Herbarium of the University of Panama (PMA). Some flowers and fruits were stored in 70% ethanol and studied using a stereomicroscope.
In March 2011, a specimen of H. berguidoi was collected in Chucantí Private Nature Reserve as part of a general floristic inventory of the area.
Each type specimen of subgenus Griggsia L.Andersson was reviewed in the JSTOR Global Plants webpage (JSTOR 2016). Some specimens of those species deposited in PMA Herbarium were also reviewed. Maps were made with the program ArcGIS version 10.1. The IUCN Red List Categories and Criteria (IUCN 2012) was used to determine the conservation status of the new species. Diagnosis. This species is distinguished from other species of Heliconia by the combination of the long petioles (up to 180 cm), glabrous but woolly at the base; blade splitting into narrow lateral segments; peduncle red, woolly with golden hairs, very long (125-150 cm); slightly flexuous rachis; bracts spirally arranged; pink flowers, perianth pubescent at the apex and staminode with cuspidate apex.
Type Description. Herb with Musa-like habit, 4.5-5 m tall, leafy shoots to 5 stems per group. Pseudostem green with brown lenticular spots, 160-180 cm tall, 6.5-7.5 cm in diameter; sheath glabrous but woolly on the margin. Leaves 4 per shoot, held more or less in horizontal position; petiole green, glabrous, woolly at the base, ca. 180 cm long, 2 cm in diameter; symmetrical blades splitting into narrow lateral segments with the base truncate, unequal, splitting into narrow lateral segments, apex acuminate, the upper surface green, midrib light green and glabrous, the lower surface light green, midrib green-reddish, glabrous, the largest blades up to 160 cm long and ca. 48 cm wide (Figures 2A, 4A, C).
Cincinnal bracts spirally arranged, ca. 25 per inflorescence, oriented ca. 120° to axis of the inflorescence, normally a sterile bract inserted in the peduncle, basal bracts separated ca. 3 cm and 1.5 cm between terminal bracts, the basal bract more elongated, outer surface pink at the base, turning red at the apex, totally velutinous with golden hairs, inner surface whitish, glabrous at the base with a few grouped hairs on both sides of the base, pink and hirsutulous with golden hairs at the margins and in the middle of the bract, ca. 12 cm long, ca. 5 cm wide at the base, l/w= 2.4 ( Figures 3A, 4D).
Floral bracts persistent, 4.2-5.5 cm long, 1.5-2.6 cm wide at the base, pink, carinate, base of the abaxial surface glabrous to slightly tomentose at the apex, adaxial surface slightly tomentose at the base, inner surface glabrous ( Figures 3B, 4F).
Distribution, habitat and ecology. Heliconia berguidoi is endemic to the Serranía de Majé, eastern Panama. It is known only from the Chucantí Private Nature Reserve (Figure 1), where it inhabits premontane forest at ca. 800 m. The canopy in this area attains a height of 20-35 m; some common canopy species are Oreomunnea pterocarpa, Ocotea sp. nov. ined., Magnolia sp. nov. ined., Quercus humboldtii, Podocarpus guatemalensis and Peltogyne purpurea. One population of H. berguidoi has been found growing in early secondary forest regenerating from previous clearance or treefall gaps. It also appears in mature forest. Mature flowers were collected in situ in March, while ex situ the species seems to flower all year round. Mature fruits have not been collected in situ. Ex situ they appear all year round.
Conservation status. Heliconia berguidoi is known only from one population in the type locality, Chucantí Private Nature Reserve. Human activities such as agriculture, cattle ranching and logging are the main threats to other populations of this species that probably exist in the forests around the reserve. These areas belong to farmers engaged in the activities mentioned above or else are public lands prone to colonization. Because of the restricted area of occupancy (AOO) estimated at 4 sq. km, and the severe threats, we consider that H. berguidoi fits the category of Critically Endangered [CR B2ab (ii, iii, iv)] of the IUCN Red List and criteria (IUCN 2012).
Etymology. The specific epithet, berguidoi, honors the Panamanian biologist Guido Cesar Berguido F., who first brought national attention to Cerro Chucantí after witnessing not only its natural splendor, but the rampant ongoing deforestation. He mustered support from family and friends to purchase a property and set it aside for conservation before the previous owners could burn the forest to ashes. He received further private support and acquired more lands to create the Chucantí Private Nature Reserve. Mr. Berguido continues to invite fellow biologists to study the flora and fauna of Cerro Chucantí, which has resulted in the discovery of various species new to science. He recently founded the Asociación Adopta el Bosque Panamá, Adopt a Panama Rainforest, ADOPTA (www.chucanti.org) to further his conservation mission. It is an honor to thus recognize Mr. Berguido´s contributions to increased biological knowledge and his great efforts to conserve the unique forests of Cerro Chucantí. His generous logistical assistance to the authors was invaluable.

Discussion
The new species of Heliconia described here belongs to the section Barbatae J.Kress ined., characterized by having the inflorescence, parts of it and/or the flowers densely pubescent with colored hairs (Kress et al. 1999, Kress andBetancur 2009) and to sub-genus Griggsia L.Andersson characterized by a pendent inflorescence (Kress 1990a). It is the first species of both subgenus and section found in Panama with pink flowers and very long peduncle, which occasionally makes the inflorescence touch the ground. Very few species in the genus Heliconia have pink flowers.
It resembles the Colombian species Heliconia rhodantha and Heliconia sanctaetheresae in the pink flowers. Also, H. rhodantha is similar to H. berguidoi in the length and width of the leaf and the truncate and unequal leaf base. Nevertheless, the three species differ in several ways. H. berguidoi has petioles up to 180 cm long with a woolly base vs. petioles that do not exceed 110 cm long and totally glabrous in H. rhodantha, and up to 220 cm and totally glabrous in H. sanctae-theresae. Inflorescences of H. berguidoi reach 220 cm long with a wooly peduncle and a slightly flexuous, velutinous rachis; the cincinnal bracts are spirally arranged and velutinous with apex not early necrotic vs. inflorescences up to 135 cm long, pubescent, velvety peduncle and a flexuous, finely pubescent rachis; cincinnal bracts distichous and finely pubescent with apex early necrotic in H. rhodantha, and inflorescences up to 67 cm long, velvety peduncle, flexuous rachis and cincinnal bracts distichous in H. sanctae-theresae. The perianth of H. berguidoi is pubescent at the apex and the elliptic staminode has a cuspidate apex vs. perianth glabrous and staminode completely linear in H. rhodantha, and perianth finely pubescent and staminode ovolanceolate in H. sanctae-theresae.
H. berguidoi is similar to H. pogonantha in its four varieties, mainly in the habit: leaves held more or less in horizontal position, leaves with unequal bases, blade splitting in segments, cincinnal bracts spirally arranged and the apex of the perianth pubescent. Additionally, it is similar to one of the varieties of H. pogonantha (H. pogonantha var. pubescens) in the combination of usually woolly peduncles and the rachises and cincinnal bracts velutinous.
H. berguidoi differs clearly from H. pogonantha in its four varieties by the petioles woolly towards the base, leaf with acuminate apex, long peduncle (125-150 cm), slightly flexuous rachis, pink flowers and staminode with cuspidate apex vs. petioles glabrous, leaf with acute apex, shorter peduncle (10-60 cm), flexuous rachis, yellow flowers and staminode with acuminate apex in H. pogonantha. Additionally, the inflorescence is one-colored in H. berguidoi vs. two-colored in three of the four varieties of H. pogonantha.
With the combination of similar habit, blade splitting in segments, woolly peduncle, monochromatic cincinnal bracts and pubescent sepal apexes, H. berguidoi is very close to two of the four varieties of H. ramonensis (H. ramonensis var. ramonensis and H. ramonensis var. xanthotricha) but it is clearly differentiated by the longer peduncle (125-150 cm), slightly flexuous rachis and pink flowers vs. shorter peduncle (10-60 cm), flexuous rachis and yellow flowers.
With the description of H. berguidoi, fifty-six native Heliconia species grow in Panama, eighteen of them endemic. This new species adds to a total of 178 species in the Neotropical region and 184 worldwide.