Who Carex about New England plant diversity?

New England Wild Flower Society—27th of June 2017

I am not new to fieldwork, but I am new to domestic fieldwork. This summer marks the first time I am muddying my boots, avoiding itch-inducing insects and learning the native flora on the lands of the United States. Previously I have worked in tropical forests, where it is no secret that hundreds of plant species can be found in an area smaller than the size of a football field. The tropical forests are diverse by all measures—it is something I have been hearing my whole life. This is why I didn’t give much thought to the diversity of New England plant life before beginning my internship.

A month in, I must admit that I still have not learned to identify every plant. In fact, a few New England genera include hundreds of species. (As a quick reminder, a genus is the first part of any organism’s scientific name. The species is the second part.) With almost 200 species, Carex takes the top spot as most speciose genus in New England. Since beginning our program on June 1st, we have only spotted and identified about ten Carex, a mere fraction. Even those I need to study more.

As a hiker we met during one of our field outings exclaimed, It takes an expert to distinguish among the Carex. Fortunately, we always carry a handy book to help us in the field and back at the office with our pressed vouchers; Sedges of Maine: A Guide to Cyperaceae, which is written by experts. Sometimes, we flip through the Sedges of Maine until we find something that looks like the Carex standing in front of us. Sometimes the species is not even listed in the book. Still, we try our best to determine the correct species from the hundreds of possibilities.

Rather than order a copy (though it’s a great resource for anyone interested), read on for a quick introduction to Carex. As the title suggests, Carex are in the sedge family, Cyperaceae. Sedges may be mistaken for grasses by an untrained eye, but sedges often have angled edges and may be triangular. Most grasses are round. Among sedges, Carex have one unique structure that sets them apart. The perigynium (PEAR-ih-GIN-eeyum) is a bottle-shaped structure that sheathes the female flower, which later becomes the Carex fruit. The Carex fruit is like a tiny nut and the perigyium shelters it from wind and animals until it is mature. Several perigynium, or perigynia, stack in a spiral shape along the Carex tip. The variation in species is often best seen by examining the texture or arrangement of the perigynia on the Carex. These are some of the first details we examine, but the width of the leaves, the height of the plant and the orientation of the perigynia are also important. Shown below are some examples of the diversity in Carex. Learn more on Go Botany.

Because the Carex are so diverse, they are found in several different habitats around New England. Our internship aids coastal restoration projects, so we will focus on the coastal Carex, but it is humbling to recognize the diversity in the genera and in New England. As well as the ease of which we can lose ourselves in the search for the right species name.

Until next time,


P.S. My brother helped me with the title. Thank you, Daniel!

Carex stricta should be one of our first seed collections (Exeter, NH)

The perigynia of Carex comosa are very spiky and sometimes painful (Exeter, NH)

Compare the number of perigynia between Carex intumescens and Carex lupulina (Exeter, NH)

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.