On Monday, Rothfels lab undergraduate student Abby Jackson-Gain and I went to the field in search of Equisetum tubers! We headed south to Butano State Park west of San Jose. Equisetum telmateia is found throughout the California coast, but is especially common in the Bay Area.
Equisetum arvense and E. telmateia are the two California species in the genus that are rumored to produce tubers along their underground rhizomes. Abby and I are hoping to take a closer look at these tubers and rhizomes by preserving them in ethanol and then making thin sections for microscopy analysis. Abby used distribution data from calflora.org and her professional mapping skills to make detailed maps of where we could find the plant.
We set off early Monday morning and were on the hunt for tubers by 10 am. Thanks to Abby's maps, we easily found a couple of individuals growing across a stream near the road (bonus points for sampling the road!). We took our shoes off and waded across to a small, scraggly Equisetum growing on the inclined bank of the stream. After digging for about an hour, we decided to try our luck elsewhere. We didn't find any tubers, but we did find this cute little salamander!
We decided to head to a different part of the park, where we would have to hike for about a mile but hopefully would find a larger population of Equisetum; we thought that if we could dig around more individuals, the density of underground organs would be higher and facilitate finding the tubers. We hiked for about 20 minutes through beautiful redwood forest, spotting tons of banana slugs along the way. We found another small patch of Equisetum, with a few more individuals than the last location, but still fairly low density.
The rhizomes we followed while digging were increasingly thin the deeper we got and broke easily. Abby's rock hammer came in handy to pry large rocks out of the dirt, but we did a lot of the digging with our hands to avoid breaking the rhizome and loosing the path down to the possible tubers below. After digging about two feet down, and with no tubers in sight, we decided to head back to Berkeley, sadly without tubers.
For our next steps, we are hoping to unearth one of the many Equisetum growing in the UC Botanical Garden, or find potted plants available for purchase in local nurseries. If anyone has tips on locating and digging up Equisetum tubers, leave me a comment below!