The kinds of traits that show genealogical relationships between species are often minute and easily overlooked.
Dr. Neil Snow, a botanist at Pittsburg State University, published a paper in 1996 that included observations of some odd-shaped hairs on three species of grass native to Africa. Their odd shape stems from distinctly swollen tips that are then pinched into a small party-hat structure at the very apex.
"A tongue-twisting technical term for that shape is 'clavicorniculate', but 'club-shaped' is a workable simplification we often prefer," remarked Snow.
In 2011, Drs. Paul Peterson and Konstatin Romaschencko, working at the Smithsonian Institution, used DNA sequences to determine that the 3 African species are related to an American species that lacks the odd-shaped hairs.
"Nobody previously anticipated a close relationship between the African and American species, particularly since the American species lacks the odd hairs". "However", added Snow, "the DNA data supporting this relationship is quite robust."
The 3 authors just published a monograph in PhytoKeys, which places the four species together for the first time in a genus called Disakisperma.
"Our research is a good example of how big, bright, flashy or sexy traits are not always the ones that help solve taxonomic puzzles", concluded Snow.
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More information: Snow N, Peterson PM, Romaschenko K (2013) Systematics of Disakisperma (Poaceae, Chloridoideae, Chlorideae). PhytoKeys 26: 21-70. DOI: 10.3897/phytokeys.26.5649