Canarina eminii is a herbaceous perennial native to eastern tropical Africa, from eastern Democratic Republic of Congo to Ethiopia and south to Malawi. It can grow either as an epiphyte or on rocky ground, and occurs in upland and riverine forests. It is one of three species in the genus, the others being Canarina abyssinica and Canarina canariensis (all are native to Africa and the Canary Islands). Canarina eminii needs high light intensity, and its ability to grow as a twig epiphyte allows it to establish high in the tree canopy. The other species of Canarina must contend with being rooted in the ground, and climb over other plants to maximize their access to sunshine.
This species possesses an ornithophilous flower, meaning that it is pollinated by birds. The blue-headed sunbird, Cyanomitra alinae is one of the numerous avian species that enjoys the nectar supplied by this flower, pollinating it in exchange. Today’s photos show two features that are typical to ornithophilous flowers: bright colouring (although red is most common), and a long tube-shaped corolla. Another feature that you cannot see from the photographs is that this flower’s nectar has a high ratio of hexose sugar, as opposed to most insect-pollinated flowers that are high in sucrose. Interestingly, Canarina eminii is one of a few species listed by Gerald Mayr in Paleogene Fossil Birds as appearing to be adapted to hummingbird pollination, but occurring in the Old World where no hummingbirds can be found. Canarina eminii lacks a perch, requiring its pollinators to hover. Mayr suggests the possibility that the species co-evolved with a hummingbird species that has since become extinct in Africa. I wonder, though, if instead it is adapted to Africa’s version of the hummingbird, the sunbird. According to a podcast about the blue-headed sunbird published by Uganda’s National Forest Authority, some sunbirds are able to take nectar by hovering, but must perch to feed.
If any of you resided in Uganda or corresponded with someone who did around ten years ago, you may have received an image of Canarina eminii in the mail, as this species was chosen as one of eight “flowers of Uganda” featured on a set of stamps.