Birders love their birds, and botanists love their flowers; rock-hounds love their rocks and minerals, and entomologists love their insects. But who loves the grasses, sedges and rushes? Even though some members of this group of plants have become global celebrities (wheat, corn, rye), most are overlooked by the majority of people, or at least they are in this country, where the knowledge of local plant life is no longer vital to our daily survival.
Those who took a basic botany course in college probably learned some version of the rhyme “Sedges have edges and Rushes are round; Grasses have joints where elbows are found,” an amusing bit of poetry designed to help students learn which of these plants were which. As with all such things, there is an element of truth in it, but every rule has its exceptions.
Learning to tell grasses from sedges from rushes can be a challenge and one that not too many are willing to tackle. We like grass in our lawns and not in our gardens (unless it is ornamental), but there our knowledge ends. In an effort to try and stimulate a little interest in these seemingly “boring” plants, let me share some quick descriptors from Grasses, an Identification Guide, by Lauren Brown.
We’ll start with grasses. Grasses have (usually) round stems that are (mostly) hollow, and long narrow leaves with parallel veins. When you get to the part of the stem where the leaf is attached, the stem is solid and a little node or joint is formed. The base of the leaf (called the sheath) wraps around the stem at this joint. On grasses the sheath is split open along part of its length. When a grass blooms, its flowers grow in two rows along the stalk. The base of the flowering portion of the plant has two empty scales (no flowers inside).
Sedges can look a lot like grasses to the untrained eye. Keep in mind, though, that they have solid stems, and their stems are often, but not always, triangular (hence, they have “edges”). The leaves, which are also long, narrow and have parallel veins, wrap around the stem, too, but their sheaths are entirely closed. The flowers grow in a spiral around the stalk, and there are no empty scales at the base of the flowering section. You will tend to find sedges in cooler and wetter areas than grasses.
This brings us to rushes. Rushes are round (but then, so are most grass stems). Their leaves are also similar to those of the grasses and sedges: long, narrow, and with parallel veins. Their stems can be solid or hollow. Unlike the grasses, however, they don’t have nodes/joints. And unlike the grasses and sedges, their flowers are terribly tiny and occur in a circle at the very tip of the stem. Described as lily-like, the flowers have three petals and three sepals. Like the sedges, rushes prefer cool, damp habitats.
Recently a friend and I were out exploring the Ice Meadows of the Hudson River, just outside Warrensburg. This is a special habitat that runs for about 16 miles along the course of the river, where the heavy snows and ice of winter collect to depths often in excess of ten feet. Spring thaws send these small glaciers grinding along the river, scouring the cobble-strewn shore and rocky upthrusts of all but the most tenacious of plants. Anything tall and resembling a shrub stands very little chance of surviving the seasonal onslaught. The end result is one of New York’s few native grasslands. But don’t expect to find something that looks like the prairies of the Midwest. These grasslands would probably be better named “rocklands,” but the term Ice Meadows suits.
Our goal this particular morning was to find and photograph dwarf sand cherry (Prunus pumila var. depressa), a lovely sprawling plant that is on the state’s protected species list. We found it blooming in all its glory and immortalized it in pixels. The highlight of the walk for me, however, was a sedge.
Like most folks, I haven’t taken the time to try and learn many grasses, sedges or rushes. Oh, I have a of couple books, and on more than one occasion I have declared I’m going to learn them, but soon they seem overwhelming in their similarity and difficulty to ID. In truth, however, there are plenty of differences if we just take the time to learn them.
This particular plant caught my eye because of its lovely colors (see photo above). I had never seen such a grass (which I incorrectly thought it was) before. The black and green striped scales were stunningly beautiful. I was seized by its splendor like a teenager dazzled by a movie star.
My botany buddy told me that it was Buxbaum’s sedge (Carex buxbaumii), a threatened species in New York State. This was another target species for our trip here, although admittedly it was secondary to the dwarf sand cherries. Most of them weren’t blooming yet, but that was fine by me, for it was the bicolored pistallate scales that had me enthralled.
It turns out that Buxbaum’s sedge, also called brown bog sedge, is a circumpolar species that has a global status of G5 (secure), while in NY its abundance is listed as S2 (imperiled). It was named after Johann Christian Buxbaum, a German botanist who lived from 1693 until 1730. I’m not sure if he “discovered” this plant or not – sources have not been forthcoming on this point. As for the label “brown bog sedge”, well, it likes wet, boggy areas, and the stripes on its scales are actually brown, not black.
The delightful discovery of this unassuming plant has renewed my interest in learning my grasses, sedges and rushes. A daunting task, perhaps, but not impossible. With the added incentive of hanging out with other amateur botanists whose knowledge of plants is nothing short of impressive, I feel pretty confident that this summer I will master at least a few of these treasures that are hidden in plain sight.