On Hydrangea peruviana, an endangered species from Ecuador, and Hydrangea oerstedii, very common in Costa Rica and Panama, and seven threatened Central and South American Hydrangeas, which have been confounded with these

Hydrangea trianae A branch with leaves seen abaxially and inflorescence buds B functionally female inflorescence with enlarged marginal flowers C basal portion of functionally male inflorescence with densely pubescent apex of the inflorescence axis, and a few open male flowers with large stamens D close-up of functionally female flowers with petals, reduced stamens and large pistils. A, C field images of collection Samain et al. 2011-064 B, D field images of collection Samain et al. 2011-067.