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Nearly 10 years ago, Karl B. McKnight, a biology professor at Saint Lawrence University in very upstate New York, came face-to-face with one of the most fundamental problems in all of science. McKnight had wanted to study some basic questions about why organisms are rare or common, and he thought heâd found the perfect test subject: mosses. In his outdoor laboratory, the 800-plus-acre Glenmeal State Park close to the Canton, N.Y., campus, these ancient plants, which evolved from filamentous green algae more than 350 million years ago, were ubiquitous and diverse. But in examining the âforests of Lilliput,â to use a perfect description from the title of John Blandâs classic book on these plants, McKnight realized something horrible.
âWe didnât know the names of any of the mosses, and there was no easy way to learn them,â the researcher told me during a phone interview. âClearly, we couldnât do ecology until weâd paid our dues in moss taxonomy and systematics, and that was going to take some time and effort.â
Lots of time and effort.
The standard guide, âMosses of Eastern North America,â is a 1981, two-volume set by botanists Howard Crum and Lewis Anderson, and while it was considered the Bible of Bryologyâthe study of mossesâworking with the 1,330-page-long tome was akin to reading the Bible in Aramaic when your first and only language was English. But McKnight is a dedicated naturalist and an environmental omnivore.
âIâve spent years learning sedges, grasses, trees, wildflowers, birds, salamanders, frogsâŠ all of creation,â he said.
Mosses were just another missing piece of the puzzle, and so he and his students took on the bryophyte learning curve.
Last year, a truly monumental effort came to fruition with the publication of âCommon Mosses of the Northeast and Appalachians,â an engaging and eye-catching field guide from the Princeton University Press. Iâve mentioned the guide in earlier editions of the Journal, and I had hoped to write about it at length in 2013. Alas, those plans had to be shelved when the drought arrived last spring, and just kept going throughout the year.
Mosses love wet weather, but they shrivel into obscurity during dry times. With this yearâs April monsoons, however, these little gems are now gorgeous and deep green.
âMosses are incredibly beautiful,â said McKnight. âBut until I started to work with them, I didnât take the time to enjoy their beauty.â
I know that feeling. In part, I suppose, it comes from our natural tendency to pay attention to the big and obvious and gloss over the minuscule and obscure. It also comes from the intimidation factor: without the right tools, or help from a master bryologist, mosses are all but unknowable beyond a cursory, âThatâs a Sphagnum, and thatâs, well, not.â
âCommon Mossesâ is the perfect tool to get you started. The book is actually the result of a four-person collaboration. In addition to McKnight, coauthors include professional bryologist Joseph Rohrer, graphic designer and illustrator Kirsten McKnight Ward (she happens to be McKnightâs daughter), and photographer Warren Perdrizet (who was one of McKnightâs students). The crew has focused on 200 species that are common in the Northeast and the Appalachian Mountains, and all it takes to begin this voyage of discovery is the guide, a 10-power hand lens, a spray bottle to rehydrate dried mossesâMcKnight calls this a âbryo-blasterââand some natural curiosity.
Taking a cue from âNewcombâs Wildflower Guide,â the much-beloved 1989 field book that emphasizes structural features of the flowers and leaves rather than blossom color, âCommon Mossesâ starts you on your journey by posing three basic questions. What is the plantâs growth form? What shape are its leaves? And does the leaf have a midrib or not? The guide then goes into considerable, user-friendly detail, complete with splendid drawings and photographs, to help you decide on answers.
First and foremost, thereâs a query about Key Feature Number One: whether the plant in question is an acrocarp, a pleurocarp, or a peat mossâthese relate to the mossâs growth form. A section about Key Feature Number Two offers instruction in determining whether the leaves are lance-shaped, ovate, hair-like, or akin to a tongue, a sickle, or a peat moss. (Thereâs also the possibility that the moss is leafless.) Finally, thereâs Key Feature Number Three, which entails ascertaining the various leaf and midrib configurations, along with âtricky casesâ that require some hand-holding for proper resolution.
âWeâve tried to provide the know-how that will guide a readerâs eyes to the characteristics that matter,â said McKnight. âIf you know just those three things, youâve made a huge step in the right direction.â
Once youâre in the proper neighborhood, you can try to work through what are known as dichotomous keysâinvestigation trails composed of couplets in which you have to choose between a series of pairs of characteristics. Say, for example, you believe youâre looking at an acrocarpâa moss with a simple or sparsely forked stemâwith hair-like, lance-, ovate-, or tongue-shaped leaves with a midrib. That gets you to Key II, and if, after careful examination of other aspects, you arrive at Couplet 19 and decide that the spore-bearing capsule has a disk at its attachment-point to the stalk, congratulations! Youâve identified a moss called Polytrichum commune, the abundant Common Haircap Moss and one of the first species I learned using this terrific volume. If the situation is otherwise, youâll just have to work your way through the next couplet, in which youâll be asked to assess moss height, the kind of forest and geographical area the plant is found in, and characteristics of the leaves that sheath the spore-capsule stalks. Then, youâll be able to decide if youâre looking at Polytrichastrum pallidisetum or P. ohioense, the Mountain or Oak Forest haircap mosses, respectively.
It sounds like a formidable task and, truth be told, it will require some careful work and study. But what, in natural history (or anything else, for that matter), doesnât involve a bit of physical and mental perspiration? You canât learn birds without spending hours in the field and hunched over your bird guidesâwell, actually, these days, you can, what with smart phone and tablet apps that do all the work for you, but thatâs just plain wrongâand it has taken years, indeed decades, on my part to develop whatever modest amount of expertise I can claim as a naturalist. It ainât easy, but the toil has been worthwhile and soul-satisfying, to say nothing of inspirational and, more often than not, fun.
So get this book and get out there to zero in on the mosses, which are at their eye-catching best right now. And unlike birds, insects, flowers, and many other things of interest, mosses are almost always available, in the same place, for study.
âI especially like their predictability,â said McKnight, who came of age as a student of fungiâhis parents, Kent and Vera, wrote the âPeterson Field Guide to the Mushroomsâ and he spent a lot of his childhood on mycological foraysâso he knows volumes about unpredictability. âEver since I started seeing the beauty and diversity of mosses, I just couldnât help myself. I was hooked, and I wanted to look closer and learn more. Beauty and predictability, along with a great challengeâwhat more could you want?â
A note to readers: If youâre interested in mosses or any other aspect of creation, Iâm leading a free public walk Saturday, April 26, from 10 a.m. until 12:30 p.m. at the Babcock Ridge Preserve in North Stonington, Conn. For more information, e-mail me: email@example.com.