A little project I have been working on over the past couple of weeks has been organizing the field office’s herbarium. It doesn’t look like it has seen much love since the times when Apiaceae was called Umbelliferae. I have been working on sorting specimens, updating family, genus and species names as well as creating some new vouchers from materials us interns have collected over the season. I’m not an overly creative person, so I figured I’d lay out the process for creating an herbarium voucher for the purpose of this blog entry. I’ll be working with curlycup gumweed (Grindelia squarrosa), a forb, so other growth forms such as shrubs and trees will require different treatment.
Step 1: Obtain a specimen
Before you make an herbarium voucher, it is necessary to find the plant that will be on the voucher. To collect a good specimen, there are a couple of things that you will want to look for. Your plant should be an average plant (not uncharacteristically large or small), be generally free of disease and damage from insects or other predators, and contain either a flower or fruit to aid in identification. Once you locate a good one, rip it out of the ground. Just get down and pull. If the soil isn’t sandy or moist enough it may help to use a shovel or other tool to remove it, ideally you will want to get some roots, but just uproot that plant from all of its friends and neighbors as completely as you can.
Step 2: Press the specimen
Once you have your target plant, you need to press it so that the 3D organism can be preserved and stored as a 2D representation of itself. You will need a plant press, some sheets of blotter paper, a piece of cardboard, and a sheet of newspaper. When pressing plants, I like to do an initial press for 15-30 minutes to make the plant more malleable. Fun fact about curlycup gumweed – the common name actually applies to the plant as it’s very sticky and made some tears in the newspaper. Once the plant bends a bit better it is easier to pose it so that some flowers are visible, some leaves are upside down and others are right side up, and the stems and branches don’t overlap. Once positioned in a pleasing pose, press again and leave for a week or two.
Step 3: Manage your information
A good voucher will have a little piece of paper in the bottom right corner of the sheet that will give you some information about the specimen. Information that you want to put down includes the scientific and common names, where you picked the plant, the general habitat and other associated species, and a collection number. This information will be helpful when you want to find a population of Grindelia squarrosa but can’t quite find a disturbed area along a roadside anywhere else. Fun fact – Grindelia squarrosa concentrates selenium from the soil, which can make it toxic when ingested by mammals. In retrospect, maybe don’t trust the common name.
Step 4: Secure the sample and file it away
After the plant has spent enough time in the press and your information is placed neatly on small piece of paper, it is time to attach all of it to a larger, acid-free piece of paper. This is your chance to hone the skills you learned in kindergarten and use glue! If you posed the plant well before pressing it it will fit nicely on the acid-free paper with no parts sticking off of the page. When gluing, make sure to leave room for the information sheet in the corner: never shall the two touch. Fun fact – unlike Grindelia squarrosa, the glue you will be using is most likely non-toxic, so feel free to go to town on that if you so desire! Just be sure to check first! Once the glue dries and everything is secure, the voucher is ready to be saved in the herbarium to help teach next year’s interns what things are.
Many thanks to Wikipedia for some of the information in this post
Shoshone Field Office