I'm not a plant expert, but I can tell monocots from dicots. Apparently the monocot lineage was founded by aquatic plants (Science mag news story, original paper) and some obscure monocot leaf structure features can be explained by that aquatic origin. I'm actually kind of surprised something like this has not been done before. I would have thought that, based on their value in agriculture, this would already have been done to gain a better understanding of their organisms. Perhaps its just an improvement of things done previously I had never heard of. This is another phylogenetic study where relationships are being better resolved by the vastly greater number of character traits that can be tracked by using markers provided in some way by molecular genetics to resolve relationships where the limited number and traditional anatomical, biochemical, and physiological traits are uninformative (too few traits spread too far to sufficiently resolve differences). An example of this can be found in fish phylogenies. Traditional fish phylogenetic studies might use a few hundred anatomical (or other kinds of) traits to determine how to categorize the relationships among many different fish species. Modern molecular studies produce many more traits to score across these species differences. Each nucleotide base in a sequence of billions of bases can be a trait (although most will get ruled out as being "un-informative"). There will still be large numbers of traits. One study (like in this freely available zebrafish study) uses ~20,000 different, non-repetitive, mapped rad sites that can be analyzed among about 20 species. It is now even possible to compare fully sequenced genomes containing a few billion bases of primary sequence information. Danio (the genus in which zebrafish are found) has experienced a lot of research on their phylogenetics. Zebrafishers appreciate the usefulness of phylogenetic information and phylogeneticists like being able to relate thier findings to a fully sequenced and annoted genome. There are also, now, a lot of fully sequenced species among the fish related to zebrafish. Researchers are passing around whole genome sequences on thumbdrives. More independently score-able markers will generally give a more strongly supported and more detailed phylogeny. Traits previously used to define phylogenetic relationships (anatomical or other traits) will become traits that are mapped onto the new phylogenetic tree, to gain a better understanding of their own evolutionary history as well as the evolution of the species in which they reside. This is happening with the plants like other well studied organisms.