A-Z of botany: Ornithophilous
In previous posts I mentioned that plants do all they can to prevent self-pollination. But that presents a problem because it means they have to get the pollen from one flower onto the stigma of another. Since most plants are unable to move, at least great distances as adult forms in bloom (unless they get humans to help), they need another agent to move the pollen to where it is needed. So plants generally use wind, animals (including insects) and water (very rarely) to do the job.
Although it is not very common in Europe, a lot of plants use birds to transfer pollen. Birds like bright colours, they do not have a great sense of smell, and they love sucrose (sugar) and these facts could help you design a bird-pollinated flower.
One of the best known is the strelitzia (above) usually called the bird of paradise. It has all the qualities you would expect: bright, scentless and dripping with nectar. But while many flowers are adapted to attracting hummingbirds and have protruding stamens and stigma and a tubular shape to fit the bird and brush pollen on its head, this one is curious because it is pollinated not by the birds’ head but it’s feet. That stout, horizontal perch, from which a succession of flowers emerge, is where the bird lands and probes the corner for nectar and as it shuffles along it opens the blue part which releases pollen and transfers it to the stigma at the tip.
Simpler flowers such as aloes (below) are also an enticing red and drip with nectar and have stout stems on which nectar-sipping birds can perch.
Wind pollinated flowers (Anemophilous) have no petals, which could catch pollen and reduce efficiency, but this method is very wasteful because most of the pollen does not reach the female flowers but end up up our noses! Going back to pollinators, there is Chiropterophilous (bats) such as cobaea, malacophilous (snails) such as aspidistra, entemophilous (insects in general) and even weirder ones such as saurophily (lizards).
Thanks for more fascinating knowledge imparted
Always wondered about the shape of strelitzias…a perch for birds. I used to pull out the new flowers on the plants which were growing along the drive in Mauritius.
Hey-are you on vacation?Miss your posts…