A New Species of Columnea (Gesneriaceae) from Ecuador with a Unique Correlation Between Leaf Symmetry and Stem Architecture

Columnea dimorpha J. L. Clark (Gesneri­aceae), a new species endemic to the Pastaza Valley of Ecuador, is described and illustrated. The species exhibits a distinctive vegetative dimorphism in which flexuous shoots consistently bear anisophyllous leaf pairs, whereas straight shoots consistently bear iso­phyllous leaf pairs. This correlated variation in stem architecture and leaf symmetry has not previously been documented in Columnea L. A conservation assessment based on the IUCN Red List Categories and Criteria supports a preliminary status of Vulnerable (VU).