Flora of the Southeastern United States
2022 Edition


Data mode


Sign up


Rhododendron Linnaeus. Rhododendron, Azalea.

Key to Rhododendron

A genus of about 860 species, shrubs and trees, mostly north temperate (centered in Himalayan Asia). Molecular evidence appears to show that Menziesia should be included in Rhododendron, and is actually closely related within Rhododendron to R. vaseyi (Goetsch, Eckert, & Hall 2005; Kurashige et al. 2001); while the urceolate corolla is rather anomalous in Rhododendron, many other morphological characters do ally Menziesia with basal clades in Rhododendron s.l.

Considerable additional work is needed to clarify Rhododendron taxonomy in our region. A new species in the "Punctatum complex" is in the process of being described. Additional entities appear to warrant recognition in the "Viscosum complex" and the "Canescens complex"; these will be more thoroughly tackled in the next edition.

ID notes: This key makes as much use as possible of vegetative characters, geography, and capsule characters; capsules are generally available for longer during the year than flowers, and even when plants are in flower, last year's capsules can often be found.

Ref: Albach & Bauer (2021); Chamberlain (1982); Craven (2011); Cullen (1980); Davidian (1982); Duncan & Pullen (1962); Fabijan (2009a) In Flora of North America Editorial Committee (2009); Goetsch, Eckert, & Hall (2005); Horn (2019); Judd & Kron (1995); Judd & Kron (2009a) In Flora of North America Editorial Committee (2009); Kron (1993); Kron & Creel (1999); Miller (2011); Stevens et al. In Kubitzki et al. (2004); Towe (2004); Zhou et al. (2008). Show full citations.

Show in key(s)

Show parent

Show children

Your browser does not support SVGs

Hover over a shape, letter, icon, or arrow on the map to see what it means. Data for arrows not developed for genera and families which may have species only occurring outside the flora area.