A remarkable new species of Brunfelsia (Solanaceae) from the eastern Andes of Central Peru

Abstract Brunfelsia cabiesesiana J. G. Graham, sp. nov. (Solanaceae), a new species from montane cloud forests of Ucayali and Pasco Departments, Peru, is described and illustrated. The new species differs from all other members of the genus Brunfelsia by its cauline inflorescences. A key to the Peruvian species of Brunfelsia is presented.


Introduction
During the course of botanical exploration in the Cordillera El Sira (see Figure 1), we encountered an interesting species of Brunfelsia with a unique combination of features diff ering from all other members of the genus. After reviewing specimens of Brunfelsia deposited in herbaria at F, HOXA and MOL (Th iers 2016), and digitized specimens available at JSTOR Global Plants (http://plants.jstor.org/), we describe a unique new species. Illustrations, photographs, a discussion of affi nities, and a key to Peruvian species of Brunfelsia is presented.
Th e Solanaceae (nightshade family) are widely distributed across the globe, including ca. 96 genera and approximately 2800 species of herbs, shrubs, trees, vines, lianas and epiphytes, with its greatest concentration of species found in the New World. Th e most recent taxonomic classifi cation by Barbosa et al. (2016) recognizes fi ve subfamilies and 14 tribes.
Brunfelsia is a neotropical genus known from the Caribbean and South America as far north as Panama. Its taxonomic history has been well documented by Plowman (1974Plowman ( , 1998, beginning with a short description, diagnosis and illustration by Plumier (1703), named (and misspelled) Brunsfelsia in honor of German herbalist Otto Brunfels. Linnaeus included Brunfelsia in the second edition of Genera Plantarum (1742) (1895), Baehni (1946), andPlowman (1974). Hunziker (2001) placed Brunfelsia as the sole genus in Tribe Fracisceae, and Olmstead et al. (2008), considering chloroplast DNA sequences, placed the genus in tribe Petunieae. Th e most recent taxonomic treatment of Solanaceae by Barbosa et al. (2016) places the genus with those taxa lacking clear relationships, i.e. Incertae sedis. It is interesting to note that the Petuniae of Olmsead et al. (2008), and Plowman's Salpiglossidae share nearly half of their genera (four of nine-Brunfelsia L., Hunzikeria D'Arcy, Leptoglossis Benth. and Plowmania Hunz. & Subils). Plowman (1974Plowman ( , 1998 considered Brunfelsia to be a distinct genus, not readily confused with other genera. Its closest relatives were considered to be the genera Browallia and Streptosolon; these are easily distinguished because the the woody habit and indehiscent capsules of Brunfelsia are not present in Browallia, nor is the twisted corolla tube and bright red-orange limb of Streptosolon found in Brunfelsia. Plowman (1978Plowman ( , 1998 recognized three subgeneric sections, Brunfelsia sect. Guianensis Plowman; B. sect. Franciscea (Pohl) Griseb., and B. sect. Brunfelsia L., based on diff erences in fl oral morphology and distinct and mostly allopatric areas of distribution. Th is classifi cation has been tested by recent molecular work of . Th eir sequence data supported two clades, an Antillean clade consist- All Brunfelsia species reported from Peru (i.e., B. chiricaspi Plowman, B. grandifl ora D.Don, and B. mire Monach.) have showy violet fl owers that fade in color as they mature, each with a distinctive white eye at the throat. No fewer than fi ve species are recorded from Andean regions of South America and ours is readily distinguishable from all members of the genus, including its nearest neighbors, by the presence of cauline infl orescences.

Taxonomic treatment
Th is new species is distinguished by its unique cauline infl orescence not encountered in any other member of the genus. A key to distinguish other known Peruvian species is provided.
Habitat and ecology. Known from central Peru in the Departments of Ucayali and Pasco where it is of extremely limited distribution but locally abundant at the type locality in the El Sira Communal Reserve. Th is understory species inhabits rocky slopes and ridge tops in cloud forests on the eastern slopes of the Cordillera El Sira, between 1100-1600 m, and has been found as a rare element in cloud forests on the northwestern slopes of the Cordillera Yanachaga, at ca. 2300 m.
Phenology. Flowering in B. cabiesesiana appears to be photomorphogenic in nature, associated with highest annual light intensities. Flowering observed in the El Sira populations is closely associated with the dry season, from August to October. Fruits appear to mature relatively slowly and are persistent, having been found green on the plant two or more months following anthesis.
Etymology. Th e species epithet honors Dr. Fernando Cabieses Molina, noted neurosurgeon, ethno-pharmacologist, author and educator. Dr. Cabieses was cofounder of the Museo de la Nación of Peru and founding rector of the Universidad Científi ca del Sur. He served as director of the Peruvian Museum of Health Sciences and the Peruvian National Institute of Traditional Medicine. Dr. Cabieses had profound interest in tropical biodiversity -both its history and utilization-and he was a tireless supporter of biodiversity conservation eff orts in Peru.
Conservation status. Th is species is of extremely limited distribution (see Figure  1), although it appears to be locally abundant as evidenced by preliminary density studies along an elevational transect near the type locality, where 18 individuals were recorded in 2000 sq. m area. Th ree of these had reached maturity, as evidenced by stunted, persistent infl orescence branches (see Figure 2). Th is species appears to be extremely rare in the Cordillera Yanachaga, ca. 125 km SW from the type location and nearly 800 m higher in elevation.
Given the extremely limited known area of occupancy of Brunfelsia cabiesesiana, and the fragmented nature of the occurrence of the two known subpopulations in Pasco and Ucayali, we estimate the Pasco subpopulation to be critically endangered and the Ucayali population to be endangered, using International Union for the Conservation of Nature Red Book guidelines (IUCN, 2012). Both of the Pasco collections were located in fragmented forests near to roads. Given that anthropogenic activity in this region continues to expand, and that only two collections have ever been made, it is considered to face an extremely high risk of extinction in the wild. Th e Ucayali subpopulation, with the benefi t of larger species densities, as well as a more favorable location inside a reserved zone, faces less threat of extinction.

Discussion
Brunfelsia cabiesesiana sp. nov. has a combination of characters that clearly separate it from other species of Brunfelsia: its strictly caulifl orous habit dis tinguish it from all other members of the genus, including the verticillate-leaved (Brunfelsia mire Monachino, Brunfelsia hydrangeiformis (Pohl) Benth.) members of the genus, as well as those with one central trunk (Brunfelsia densifolia Krug & Urb., Brunfelsia mire, Brunfelsia chiricaspi Plowman).
Th ere is a clear divergence in elevational range between the Yanachaga and El Sira populations of B. cabiesesiana. A similar elevational-displacement phenomenon has been recorded for other organisms in the Cordillera El Sira. Terborgh and Weske (1975) noted a downward-displacement in elevation for species ranges of birds in the Cordillera El Sira, compared with the Cordillera Vilcabamba, with displacements of approximately 800 m. A similar pattern of elevational range displacement between the Cordilleras Yanachaga and El Sira, in both vascular plants and bryophytes, has been observed during our own fi eld research.