International Aroid Society

I fell behind on reading the last issue of Aroideana, so it was only just today that I read Tom's article on "black" Anthuriums. He notes that the known species are all in different sections, hence the black spathe is a plesiomorphic trait (that is, inherited from a common ancestor). I wonder about that -- why he believes it is plesiomorphic rather than homoplastic (that is, the result of convergence). He noted that the black-spathed species all come from Colombia and Ecuador, at higher elevations where the climate is more temperate. To me, this suggests at least the possibility of homoplasy, if, as Tom suggests, the dark color allows the inflorescences to collect heat and become warmer than their surroundings.

What set my mind thinking down this path was the memory of visiting Micronesia in 2008. One of the four main islands is Pohnpei, and Pohnpei is odd in that six of its 19 resident birds, 32%, in four different families, are either black, or give the impression of being black, and most have close relatives that are not black. There is nothing so unusual about the island swiftlet's color, since swifts as a group tend to be dark, but that is just the beginning. The Pohnpei lory is the only parrot in Micronesia, and is such a dark purple as to appear black; other lories of the world are in reds and greens. The mostly-black Micronesian starling occurs on several of the islands besides Pohnpei, but there is a second, endemic species, the Pohnpei mountain starling, that is even blacker. The two Pachycephalidae, the Palau fantail and the Palau flycatcher, are also both black, but in both cases, the nearest relative is other colors: the other fantails in Micronesia are shades of brown or rufous, and the other three Myiagra flycathcers throughout Micronesia are only blue-black on the upperparts of the males, which are white and rufous below. I remember wondering at the time, what was it about the environment in Pohnpei that caused its birds to evolve black coloring, in contrast to those of neighbor islands? Now I have the same wonderment about Tom's "black" Anthuriums.

Jason Hernandez

Naturalist-at-Large