1 Studies in Swartzia (Leguminosae−Papilionoideae) of Colombia with emphasis in sect. Terminales LIZ KAREN RUIZ BOHÓRQUEZ Director: Ph. D. Santiago Madriñan Maestria en Ciencias Biológicas con énfasis en Botánica y Sistemática Escuela de Post−Grados−Departamento de Biología Universidad de los Andes Mayo de 2013 2 TABLE OF CONTENTS Abstract Introduction Materials and methods The genus Swartzia sect. Terminales Species of sect. Terminales found in Colombia Key to species of Swartzia sect. Terminales in Colombia Taxonomic Treatment 1. Swartzia amplifolia Harms 2. Swartzia argentea Spruce ex Bentham 3. Swartzia cabrerae R.S. Cowan 4. Swartzia cardiosperma Spruce ex Bentham 5. Swartzia flavescens (Cowan) Suessenguth 6. Swartzia leptopetala Bentham 7. Swartzia macrophylla Willd. ex Vogel 8. Swartzia magdalenae Britton & Killip 9. Swartzia santanderensis R.S. Cowan 10. Swartzia schultesii R.S. Cowan 11. Swartzia sp nov. 1 L.K. Ruiz, Torke & Mansano 12. Swartzia sp nov. 2 L.K. Ruiz, Torke & Mansano 13. Swartzia sp nov. 3 L.K. Ruiz, Torke & Mansano 14. Swartzia sp nov. 4 L.K. Ruiz, Torke & Mansano Acknowledgements Literature cited List of exsiccatae 3 Studies in Swartzia (Leguminosae−Papilionoideae) of Colombia with emphasis in sect. Terminales ABSTRACT The genus Swartzia (Leguminosae−Papilionoideae−Swartzieae) includes nearly 200 species and is particularly diverse and abundant in the tropical forests of the Amazon basin, the Guianas and northern South America (Torke & Zamora, 2010); in Colombia it is quite diverse on both sides of the Andes, in the inter−andean valleys and in the low and humid lands. It grows from sea level to 2200 m altitude. Swartzia has been divided into 15 sections. Among them, Terminalesis the largest and most diverse in Colombia; it can be recognized by the combination of pedicels without bracts, flowers with a yellow petal, the stipe and style reduced in relation to the ovary, with numerous seeds and moniliform ovary (Torke & Schaal 2008; Torke & Mansano, 2009). The research has centered on taxonomic studies and field observations of the Colombian species of Swartzia sect. Terminales. In the course of the investigation, material from 13 herbaria both in Colombia and the United States totaling ca. 2000 specimens, was studied. Variability of morphological characters was determined for each species by measuring both vegetative and reproductive organs. Field collections were carried out in Antioquia, the middle Magdalena valley and Vaupes. It is concluded that ten species–out of 23 species so far described for South America−grow in Colombia; in addition, four species are described as new to science and one species is reinstated. Key words: Antioquia, Colombia, Magdalena River valley, Neotropics, Swartzia, Taxonomy, Vaupes. 4 INTRODUCTION The plant family Leguminosae is one of the largest groups of Angiosperms (flowering plants) in the world, with about 730 genera and 19.300 species (Cardoso et al., 2012), it is cosmopolitan in distribution and is present in almost all of the earth´s biomes, from deserts to wet tropical forests. The Leguminosae can be herbs, shrubs or very large trees and are well represented in the Colombian flora (Forero, 2005). A good example of this diversity is the genus Swartzia Schreber of the tribe Swartzieae , that includes nearly 200 species and is particularly abundant and diverse in the tropical forests of the Amazon basin, the Guianas and northern South America (Torke & Zamora, 2010); species of Swartzia grow from sea level to 2200 m altitude, and several species can grow and coexist in the same forest zone, showing interesting and complex relations with other plants, pollinators seed dispersal agents, herbivores and even human beings. Given its species richness, its ecological complexities and ubiquity in the neotropical forests, the genus constitutes a model system to understand the origin and sustainability of plant diversity in the neotropics. Species of Swartzia are also important ecological and biogeographic entities due to their high diversity and notable endemism in neotropical forests. The genus Swartzia (Leguminosae) is highly diversified in the wet lowlands of Colombia on both sides of the Andes Mountains, as well as in the large valleys that separate the Andean Cordilleras. Documentation of this diversity, much of it threatened, has proceeded at a slow pace. The existing herbarium collections of Colombian Swartzia number fewer than 2000 and are too few to give more than a cursory view of nation−wide taxonomic diversity, morphological 5 variation and species distributions. To complicate matters, many collections are not deposited outside of Colombia, or even beyond the herbarium of origin. Nevertheless, data are substantially more numerous than they were when Richard Cowan undertook the last comprehensive taxonomic study of Swartzia. Collections made subsequent to the publication of his monograph (Cowan, 1968) account for approximately 80 percent of the existing material. In addition to the revision by Cowan (l.c.) for Flora Neotropica, the genus has been studied in recent years and from different perspectives by Torke & Schaal (2008), Torke & Mansano (2009), and Torke & Zamora (2010). Britton & Killip (1936) mentioned 7 species for Colombia. The lack of information on Colombian taxa is evident in works like Cowan’s. As part of a long−term systematic study of the genus throughout its range, Torke and collaborators have examined much new material, along with older collections, in Colombian herbaria and abroad. They have concluded that approximately 65 species of Swartzia occur in Colombia, doubling the number recorded from the country by Cowan (1968). While some of the new records involve nomenclatural changes (e.g., Torke & Mansano, 2009) or represent range extensions of species that were known to Cowan or species that have been subsequently described in the literature; the majority are of species new to science. The genus is characterized by being trees with unifoliolate or compound leaves, moniliform fruits and just one petal that may be absent in some cases. Swartzia has been divided in 15 sections (Torke & Mansano, 2009). Among them, Section Terminales is the largest and most diverse in Colombia. It can be recognized by the combination of pedicels without bracts, flowers with a yellow petal, the stipe and style reduced in relation to the ovary, with numerous seeds and moniliform ovary (Torke & Schaal 2008; Torke & Mansano, 2009). Although section Terminales is most diverse in Amazonia, a secondary radiation of the group has taken place in 6 the Pacific lowlands and inter−Andean valleys of Colombia, where a number of species are highly localized and threatened by habitat destruction, including the four species described herein. In the course of the investigation, field collections were carried out in Antioquia, the middle Magdalena river valley and Vaupes. Part of the material collected has been instrumental in the process of identifying and describing four new species. As an additional result of the field work, a species of Swartzia was found growing at 2200 m altitude, the highest record for the genus in Colombia, making it a component of the pre−montane wet forest (“bosque humedo premontano”; bh−PM). It is concluded that ten species – out of 23 species so far described for South America − grow in Colombia; in addition, four species are described as new to science and one species is reinstated. Each species was categorized regarding its conservation status following the criteria established by the International Union for the Conservation of Nature (IUCN). On the basis of a detailed analysis of herbarium material and taking into consideration de geographic distribution of the species, the existence of the S. amplifolia / S. macrophylla complex is proposed. This artificial complex is recognized on the basis of several morphological characters that are shared by both taxa; there are, however, marked differences in the geographic distribution of the populations involved. Additional field, herbarium and laboratory studies will be needed in order to sort out this complex, as well as to learn about plant−animal relationships, pollinators, and the influence of ants in the development of certain species of Swartzia. 7 MATERIALS AND METHODS The research here presented was based mainly on the study of plant collections deposited in the following Colombian and U.S. herbaria: Herbario Nacional Colombiano (COL), Herbario Amazónico Colombiano (COAH), Herbario, Universidad Tecnológica del Chocó, Quibdó (CHOCO), Herbario, Universidad Distrital, Bogotá (UDBC), Instituto Alexander von Humboldt (FMB), Universidad de Antioquia (HUA), Jardín Botánico de Medellín (JAUM), Universidad Nacional sede Medellín (MEDEL), Universidad de los Andes (ANDES), Universidad del Cauca (CAUP), New York Botanical Garden (NY), United States National Herbarium (US) and Missouri Botanical Garden (MO). Field work was carried out in Colombia during 2010; at that time, the author traveled to Antioquia, Vaupés and the middle Magdalena river valley to collect and observe in the field as many species of Swartzia as possible. The author then (2013) made a short field trip to the municipality of Caldas, department of Antioquia. The present paper includes detailed descriptions of all 14 species found in Colombia, together with information on geographic distribution in the country, altitude above sea level, habitat, phenology, specimens examined and taxonomic notes. A key to the species of Swartzia sect. Terminales