Bomarea pastazensis (Alstroemeriaceae), an exceptionally small new species from the eastern Andean slopes of Ecuador
 
 
John L. Clark, Alisson Fierro-Minda, Nolan Exe, Mia Johnson, Carrie M. Tribble, Lou Jost
 
Abstract
Recent field research on the eastern slopes of the Andes resulted in the discovery of a new species of Bomarea from the Cerro Candelaria Reserve in the Tungurahua province of Ecuador. Bomarea pastazensis is the second smallest species in the genus and differs from the smallest by the presence of glutinous trichomes on the ovary, glabrous sepals, and greenish-yellow petals with purple spots. Based on IUCN guidelines, a preliminary conservation status is assigned as Vulnerable (VU).
Resumen
Recientes investigaciones de campo en las estribaciones orientales de los Andes dieron como resultado el descubrimiento de una nueva especie de Bomarea en la Reserva Cerro Candelaria en la provincia de Tungurahua en Ecuador. Bomarea pastazensis es la segunda especie más pequeña del género y se diferencia por la presencia de tricomas glutinosos en el ovario, sépalos glabros y pétalos verdes con amarillo y manchas moradas. Con base en los lineamientos de la IUCN, se le asigna un estado preliminar de conservación de Vulnerable (VU).
Key words
Alstroemeriaceae, Andes, Bomarea, Ecuador, endemism, taxonomy
Introduction
There are more than 100 species of Bomarea Mirb. in South America (Hofreiter 2006) and 39 species in Ecuador (Harling and Neuendorf 2003). The description of Bomarea pastazensis brings the total diversity to 40 species in Ecuador. The most recent monograph of Bomarea was provided by Hofreiter and Tillich (2002) and included an updated classification system based on Baker (1888) that recognized the following four subgenera: Baccata Hofr., Bomarea Baker, Sphaerine (Herb.) Baker, and Wichuraea (M. Roemer) Baker. More recently, molecular phylogenetic studies have failed to support the monophyly of these subgenera (Alzate et al. 2008b; Tribble et al. 2022), suggesting that many of the morphological characters that previously defined infrageneric classification are homoplastic or have evolved convergently. Alzate et al. (2008b) showed that traditionally recognized subgeneric ranks proposed by Baker (1888) and Hofreiter and Tillich (2002) are polyphyletic. Tribble et al. (2022) described three main clades within Bomarea, but no updated classification system has yet been proposed. In the present study we recognize the lack of strongly supported subgeneric ranks (Alzate et al. 2008b; Tribble et al. 2022) and discuss the traditional subgenus that most resembles Bomarea pastazensis.

Bomarea pastazensis most closely resembles the morphologies associated with the subgenus Sphaerine because of the following characters (Hofreiter 2005): erect or hanging habit [mostly non-twining except for B. coccinea (Ruiz & Pav.) Baker] (Fig. 1E), resupinate leaves (Figs 1D, 2E), and inferior ovaries (Figs 1A–C, 2A). Recent molecular work suggests that Sphaerine is non-monophyletic and some morphological characteristics of this group are likely adaptations to environmental conditions (Alzate et al. 2008b; Tribble et al. 2022). The subgenus Sphaerine ranges from the northern Andes of Colombia and Venezuela to Bolivia. In Ecuador, the subgenus is distributed mainly on the eastern Andean slopes. A detailed taxonomic history and overview of Sphaerine was provided by Hofreiter (2006), including updated circumscriptions and two new species. The addition of Bomarea pastazensis brings the total diversity of subgenus Sphaerine to 13 species.

Figure 1. 
Some species of Ecuadorian Bomarea subgenus Sphaerine A Bomarea brachysepala B Bomarea distichifolia C Bomarea hieronymi D resupinate leaf (rotated petiole indicated with white arrow) of Bomarea hieronymi E terrestrial habit (non-twining) of Bomarea hieronymi. Photos A, B by N. Exe, C–E by J.L. Clark (J.L. Clark 17350).