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Vouchering in the Fells

Vouchering in the Fells

By Bryan Hamlin
A thorough plant survey of the Fells was published in 2012 in the botanical journal Rhodora. This paper reported 868 species of vascular plants in the reservation – a high number reflective of the many different habitat types resulting from the complex topography and geology of the Fells.

The Harvard University Herbarium is happy to accept what are termed ‘vouchers’, that is samples of these many different plants as evidence for many years to come of what in the first decade of the 21st century was growing in the Fells. Most species have by now been vouchered, and we’re down to the last fifty or so. This task gets increasingly challenging – where did I see that plant back in 2005?!

It is important to voucher the plant with reproductive parts i.e. flowers or fruit, or better still – both. Nowadays a GPS reading is taken of the location, along with other data such as the plant’s abundance, the type of habitat and a short list of the other species around. The sample is then pressed and dried, treated to kill any insects, and then mounted on special quality paper sheets always 11.5 x 16.5 inches in size. My colleague, Walter Kittredge, who has vouchered many of the plants of the Fells and is Associate Curator at the Harvard Herbarium, types up a label containing the information gathered at the time of vouchering. A small envelope is also attached to one corner of the sheet for seeds and leaves that may fall off. Once the identity of the species is confirmed by an expert, the voucher is then accessioned into the herbarium.

Here is what a mounted specimen of Red Currant – Ribes rubrum looks like ready to be accessioned.

Red Currant - Ribes rubrum

Red Currant – Ribes rubrum


Today, with the help of the Massachusetts Water Resource Authority (MWRA) I was able to voucher Butterfly-weed – Asclepias tuberosa from inside the fenced off area of the Covered Reservoir.

Butterfly-weed - Asclepias tuberosa

Butterfly-weed – Asclepias tuberosa

The work continues, and is fun.


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