In The origin of species, Darwin (1859) asserted the
importance of homology—the similarity of traits resulting
from shared ancestry—for understanding evolutionary relationships.
Although the importance of homologous traits
(including sequences of DNA, genes, and proteins) in
reconstructing phylogenies is widely recognized, actually
identifying them remains a challenge. Nowhere is this
challenge more evident than in the history of the placement
of carnivorous plants in angiosperm phylogenies (Juniper
et al., 1989).