So I was standing in the shower, thinking about dissertation topics. It hits me that a really good way to improve phytolith analysis would be to differentiate between species better. Right now, phytolith analysis can only differentiate down to the genus level at best. Is it possible to see a difference between species? I can think of two plant taxa to look into. First, the genus Festuca (bunchgrasses). These are fairly common in the American west, and with lots of species it would be relatively easy to check them out. Since this is a grass genus, there would be lots of phytoliths in the biomass. Second, the genus Artemisia (sagebrush). Artemisia is about as cosmopolitan as you can get in the American west. It's everywhere. I'd be mostly interested in the subgenus Tridentatae, as that's where I'd find the sagebrushes. The sagebrush species are all very closely related, having diverged only a few million years ago. It may be very hard to differentiate them. If I wanted to get even more specific, I could zoom in on big basin sagebrush, Artemisia tridentata. This sagebrush has six recognized subspecies. Are there any differences in those?
I think it would be fairly easy to look at the differences in these taxa. I'd just need to go out, take some plant samples, process them, and then look at them under the microscope. I'd be looking for three things. First, does a given species display unique phytoliths, or signature shapes? If these are found, then I'd know that every time I found one of those signature shapes in a soil sample, that that given species must have been present. Second, are there any differences in the ratios of phytolith shapes? A given species produces many phytolith shapes. What is the ratio of these shapes? Is there a difference in the ratios between species? Third, how much phytoliths are present in a given plant at any one time? For example, does a large bunchgrass species with lots of biomass produce more phytoliths than a smaller species? Is this reflected in the soil? This may require a determination of the total amount of phytoliths produced by a plant over its entire lifetime.