Distribution: neotropics (Calcicola, Malpighia, Mascagnia); paleotropics: Africa (Diaspis, Triaspis), East Africa and Arabian Peninsula (Caucanthus), Asia (Aspidopterys), Madagascar (Digoniopterys, Madagasikaria, Microsteira, Rhynchophora).
The large and strongly supported Malpighia clade is rooted in the neotropical genus Mascagnia, which retains characters of its near sisters in the family, notably the habit of twining vines and fruits breaking apart into samaras with a membranous lateral wing. Those characters are retained in many, but not all, of the genera of this clade. The two other neotropical genera, Calcicola and Malpighia, have abandoned the vining habit; all their species are shrubs or small trees. Calcicola still has lateral-winged samaras, but in Malpighia (except for the anomalous M. leticiana) the winged samaras have been replaced by fleshy, bird-dispersed fruits, which show evidence of their winged origin in the crests on the endocarp buried in the flesh.
The rest of the Malpighia clade comprises paleotropical genera. Our phylogenetic tree for the clade, based on the tree in Davis & Anderson (2010 [pdf]), is suspect in one respect. It shows the Old World subclade as sister to Malpighia, but with little bootstrap support (60%), and that agrees with the morphology, because Aspidopterys is morphologically much more similar to Mascagnia than it is to Malpighia. In fact, in its samaras Aspidopterys is essentially identical to Mascagnia, so it would not be surprising if a future tree with better internal resolution placed the paleotropical subclade as sister to Mascagnia rather than Malpighia. Except for the very peculiar genus Rhynchophora, all the other genera have more or less mascagnioid samaras, although in several genera the samaras appear not to separate from each other at maturity. Microsteira would seem to be quite different, but its Y-shaped samara, which resembles that of the triopteroid species of Mascagnia, is essentially a mascagnioid samara that is indented at the apex and pinched inward at the sides.
In Mascagnia the fruit is subtended by a fleshy, more or less three-lobed disc that becomes evident below the torus after the samaras are shed. That disc is a synapomorphy of this clade, found only in the genera that have winged fruits breaking apart into separate samaras at maturity. It seems to have been lost in the genera with indehiscent fruits, such as Malpighia, Caucanthus, and Rhynchophora.
This clade is also interesting in its biogeography. Mascagnia is mostly South American, with relatively few species that reached Central America, Mexico, and the West Indies; it thus resembles many genera of Malpighiaceae. Calcicola, on the other hand, is wholly Mexican, and Malpighia is mostly Mexican and West Indian, which suggests that it may have originated in either Mexico or the West Indies. The resolution of the Old World subclade in our phylogenetic tree is not well supported, except for the four genera in Madagascar, but the geographic distribution of the Old World genera suggests that the first immigrant from the New World may have arrived in Asia, with descendants then making their way from Asia to Africa and from there to Madagascar.
The genera of this clade that are endemic to Madagascar (Digoniopterys, Madagasikaria, Microsteira, and Rhynchophora) are functionally dioecious, a breeding system that is known in several other clades but not common in Malpighiaceae.