The Vasculum

I have always felt that field biologists are primarily explorers. Even as we revel in a new discovery, our minds are already drifting off to the next expedition. We all have our own lengthy lists of locales and taxa for which we pine. For me it is usually a certain species, but with some groups I would be equally happy to find any member of the genus. The genus Isoetes (Isoetaceae) is once such group. With my feet and eyes, I have covered a lot of ground in Missouri and the Midwest. Yet, somehow I have never crossed paths with an Isoetes . I have molested many sterile Eleocharis and Juncus in the distant hope that they were Isoetes . Experience has told me, I will know one when I see one. Friday morning, I met with the esteemed Missouri Botanist Alan Brant for some stream corridor work in the St. Francois Mountains (center of uplift for the Ozark Plateau characterized by a preponderance of rhyolite). He enticed me along on the trip with the promise of nice weather and possibility of...

Whenever one thinks of Tallgrass Prairie grasses, the “big four” often come to mind. The “big four” being Big Bluestem ( Andropogon gerardii ), Little Bluestem ( A. scoparius ), Switch Grass ( Panicum virgatum ) and Indian Grass ( Sorghastrum nutans ). Though they represent only a fraction of the grass diversity that prairie is capable of expressing, they often make up a significant portion of the vegetative biomass. All four of these species are easy to identify by their flowering structures and many folks working in prairies can distinguish these species by vegetative (non-floral) means. It is really just a matter of stem bases; Panicum virgatum is the only one with a circular cross section, both A. gerardii and S. nutans have an oval cross section and A. scoparius has a very flat base. Andropogon gerardii and S. nutans can then be separated by ligule length where S. nutans has a prominent and cartilaginous ligule compared to the shorter membranaceous ligule of A. gerardii . Y...