A new species of Espeletiopsis (Millerieae, Asteraceae) from Colombia

Abstract A new species of Espeletiopsis was found in two small páramos of Norte de Santander, Colombia. The species is named Espeletiopsis diazii honoring the contributions of Santiago Díaz-Piedrahita in recognition of his vast knowledge of the Compositae in Colombia. This is a very distinctive species, markedly different from most of the Espeletiopsis present in Colombia. The new species is closely related to Espeletiopsis caldasii and Espeletiopsis santanderensis, but differs in having (1–)4–6(–7) capitula, with very short peduncles, and capitula arranged in a compact or densely glomerate cyme. With a total distribution area of less than 75 km2, this species is probably critically endangered or imperiled.


Introduction
At the high elevations of the tropical Andes, typically above 3600 m, trees and shrubs disappear gradually, opening the space for the páramo. With an estimated age of 2-4 million years (Van der Hammen et al. 1986), the páramo ecosystem is relatively young and yet is widely regarded as the world's most diverse high-elevation ecosystem (Lu-teyn 1999;Rangel-Ch. 2000;Sklenář et al. 2005), and probably the fastest evolving biodiversity hotspot (Madriñán et al. 2013). One of the unique characteristics of the páramo is the presence of frailejones, the name being generally used to refer to all the species within the subtribe Espeletiinae Cuatrec. (Asteraceae: Millerieae).
Th e genus Espeletiopsis is distributed from the central Andes of Venezuela to the Cordillera Oriental (Eastern Cordillera) in Colombia, approximately from 70.8°W and 8.9°N to 74.3°W and 4.1°N). Only fi ve species are found in Venezuela (four of them endemic to the country), whereas Colombia has 18 species. According to Cuatrecasas (2013), Espeletiopsis represents a derived line of evolution within Espeletiinae, being mainly adapted to lower elevations. Twenty species are found at elevations of 3200-3400 m in the subpáramo belt, two species grow as low as 2200 m, and one reaches 4500 m.
Most of the species are restricted to one continuous páramo and have relatively narrow distributions (<1000 km 2 ). Seven species have distributions of 2500-4750 km 2 , six species are distributed in areas of less than 20 km 2 , and six species are known from less than seven collections, including two with only the type collection (Diazgranados 2012a; b). In the last ten years four new species of Espeletiopsis have been described from Colombia (Díaz-Piedrahita and Obando 2004;Díaz-Piedrahita and Rodriguez-Cabeza 2008;Díaz-Piedrahita et al. 2006), and it is not surprising that more new species will be discovered in uncollected páramos.

Methods
Th e Páramo de Cáchira (also called Páramo de Guerrero; see Fig. 4) and the adjacent Páramo de los Ranchos are located in a region of Norte de Santander (Colombia) of very diffi cult access. North from the Páramo de Arboledas, these are probably the last páramos of the Eastern Cordillera before the Ocaña depression. For decades the area was unsafe, and the only road that reaches these páramos was almost impassable. Still now, the area is fl oristically poorly known. Material of the new species was collected during an expedition in 2009, and duplicates distributed to COL, ANDES and HECASA. Additional duplicates will be distributed to other herbaria, including US and MO. Micrographs were taken by the fi rst author at the Scanning Electron Microscopy Laboratory of the National Museum of Natural History, in Washington DC. Lauren Merchant from Saint Louis University provided the illustrations, which were funded by the Missouri Botanical Garden. Diagnosis. Sessile rosette of whitish appearance, related to Espeletiopsis santanderensis , but with smaller leaves, capitulescence compact with a dense glomerate cyme of (1-)4-6(-7) capitula and short peduncles, and disc fl owers with corolla lobes glabrescent.
Distribution. Endemic to Colombia. Th is species has been found only in the Páramo de Cáchira (or Páramo de Guerrero), and in a smaller adjacent páramo, called Páramo de los Ranchos, at elevations of 3300-3500 m (Fig. 4). Th e area of distribution is less than 75 km 2 .

Ecology.
A large population of several hundreds or thousands of individuals growing in the grasslands of the páramo proper was observed (Fig. 4). Other Espeletiinae found in the area are: Espeletia brassicoidea Cuatrec., E. conglomerata Cuatrec. and Libanothamnus occultus ssp. oroquensis Cuatrec.
Etymology. Th e specifi c epithet of this new species, "diazii", is dedicated to Santiago Díaz-Piedrahita, Colombian botanist, for his vast contributions to the knowledge of the Compositae of his country.
Conservation status. Th e preservation of this species is linked to the preservation of the Páramo de Cáchira and the Páramo de Los Ranchos. Th ese are both very small páramos (70-80 km 2 of total area), likely sensitive to climate and land use change, with substantial fragmentation, and without any legal measures of protection. Th erefore, E. diazii is probably Critically Endangered (CR, according to the IUCN criteria: extent of occurrence estimated to be less than 100 km 2 , habitat fragmentation, and likely decline of the extent of the páramo; http://jr.iucnredlist.org/documents/redlist_ cats_crit_en.pdf), or Critically Imperiled (G1, according to NatureServe; http://www. natureserve.org/explorer/ranking.htm).

Discussion
Espeletiopsis diazii is a very distinctive species. Th e laminae lack pseudopetioles and the sheaths are oblong, rectangular, not broadening toward the base, the features being rare in Espeletiopsis but characteristic of Espeletia sect. Weddellia Cuatrec. (8 species) of the páramos of Apartaderos, Piñango and Timotes in Mérida, Trujillo and Lara, Venezuela. However, monochasial capitulescences with several alternate bracts along the scape place this species within Espeletiopsis .
Th e new species is probably related to a group of 10 species of Espeletiopsis with sessile caulirosula habit (sensu Cuatrecasas 2013) from the páramos. Two of these ( E. angustifolia (Cuatrec.) Cuatrec. and E. pannosa (Standl.) Cuatrec.) also have an indumentum that is silvery-sericeous, but diff er from the rest in having white-purple ligulae.  E. caldasii ) have a reduced silvery-sericeous indumentum and reduced oblong sheaths. Espeletiopsis caldasii has capitulescences monocephalous, and E. santanderensis has capitulescences spreading (Fig. 5). Both species grow in the páramos of Santander-Norte de Santander, but relatively distantly from the population of E. diazii (Fig. 4).