Molecular phylogenetic relationships and a revised classification of the subfamily Ericoideae (Ericaceae) Emily Gillespie * , Kathleen Kron Department of Biology, 226 Winston Hall, Wake Forest University, Winston-Salem, NC 27109, USA article info Article history: Received 11 November 2009 Revised 10 February 2010 Accepted 19 February 2010 Available online 1 March 2010 Keywords: Bejarieae Bryantheae Empetreae Ericeae Ericoideae Molecular phylogeny Phyllodoceae Rhodoreae Classification abstract Subfamily Ericoideae (Ericaceae) includes 19 genera in five recognized tribes. Relationships involving the deepest nodes have been difficult to resolve, limiting the potential for further cladistic studies within the Ericoideae. The current study analyses six molecular markers using Bayesian, Maximum Likelihood and Maximum Parsimony methods to improve phylogenetic resolution within the Ericoideae. Two large clades were discovered. One clade includes the Phyllodoceae and Bejaria. The sister clade includes the Empetreae + Diplarche, Ericeae, Rhodoreae, and a clade comprised of Bryanthus and Ledothamnus. The cur- rent study improves upon the resolution of the phylogeny of the Ericoideae, particularly demonstrating support for the deepest nodes. Based on these results, we propose to retain the Ericeae, expand the Phyl- lodoceae to include Bejaria, expand the Empetreae to include Diplarche, retain the Rhodoreae (without Diplarche), dismantle the Bejarieae, and construct a new tribe, Bryantheae (Bryanthus and Ledothamnus). Ó 2010 Elsevier Inc. All rights reserved. 1. Introduction The subfamily Ericoideae (Ericaceae) is a morphologically diverse and geographically widespread group of plants comprised of approximately 1790 species in 19 genera (Mabberley, 1997; Luteyn, 1995; Stevens, 2001). These include two large genera: Rhododendron L. (850 spp.) and Erica L. (765 spp.), and several genera of small to moderate size: Bejaria Mutis ex L. (15 spp.), Elliottia Muhl. ex Elliott (4 spp.), Kalmia L. (8–10 spp.), Ledothamnus Meisn. (7 spp.), and Phyl- lodoce Salisb. (7–9 spp.). Most genera in the Ericoideae have 1–3 spe- cies and include Bryanthus Gmel. (1 sp.), Calluna Salisb. (1 sp.), Ceratiola Michx. (1 sp.), Corema D. Don (1 sp.), Daboecia D. Don (1 sp.), Diplarche Hook. & Thompson (2 spp.), Empetrum L. (3–18 spp.), Epigaea L. (3 spp.), Kalmiopsis Rehder (2 spp.), Rhodothamnus Rchb. (2 spp.) and Therorhodion Small (3 spp.). While many species in the Ericoideae are north temperate in distribution (e.g., Kalmia, Phyllodoce, many Rhododendron), genera such as Bejaria (mostly South American), Ledothamnus (Guyanan tepuis), Erica (mostly South African), Empetrum (amphi-polar) and a number of southeast Asian Rhododendron extend the distri- bution of Ericoideae well into the Southern hemisphere (Mabber- ley, 1997; Stevens, 2001). The Ericoideae are morphologically diverse in many aspects. Leaves may be plane or revolute; the inrolled form being the eri- coid leaf seen in Erica and several other members of Ericoideae. Indumentum is highly variable within Ericoideae. The more com- plex types of indumentum include hairs with intricate three- dimensional branching and multicellular lepidote scales (e.g., some Rhododendron). Floral morphology in Ericoideae ranges from poly- petalous to gamopetalous. Some gamopetalous flowers appear to be secondarily polypetalous; e.g., Loiseleuria and Leiophyllum are now known to be derived from within the gamopetalous genus Kalmia (Kron and King, 1996). Although usually actinomorphic, many species possess flowers that are slightly bilaterally symmet- rical (e.g., Rhododendron). Urceolate, funnelform and rotate floral shapes occur in this group and there is also variation in style artic- ulation and orientation (Kron et al., 2002). The taxonomic history of the Ericoideae is complex (Table 1), but a brief introduction helps to illustrate the degree to which the divergent morphologies of this group have been troublesome to many experts interested in reconstructing its evolutionary his- tory. Repeated taxonomic changes associated with some genera (e.g., Elliottia, whose four extant species have belonged to as many as three genera and two tribes) have created a fragmented taxo- nomic history (Copeland, 1943; Cox, 1948; Stevens, 1971), which reflects the degree of morphological divergence seen in the Ericoideae. 1055-7903/$ - see front matter Ó 2010 Elsevier Inc. All rights reserved. doi:10.1016/j.ympev.2010.02.028 * Corresponding author. Fax: +1 336 758 6008. E-mail addresses: gillel5@wfu.edu (E. Gillespie), kronka@wfu.edu (K. Kron). Molecular Phylogenetics and Evolution 56 (2010) 343–354 Contents lists available at ScienceDirect Molecular Phylogenetics and Evolution journal homepage: www.elsevier.com/locate/ympev