Winter Sampler

Vernal witchhazel

Vernal witchhazel

For the two dozen or so people who came to the Arboretum for Sunday’s guided tour, it turned out to be more of an early spring sampler. Unseasonably warm temperatures have brought out some phenomena we don’t usually see until March.

Trail conditions are still on the muddy side, which limited our activity a bit. I had scouted on Saturday and knew where the gushiest sections were, and how to avoid them.

If I said the tour featured “cats and fleas,” would it intrigue you? Read on: we found blooming pussy willows and many, many snow fleas. And much more!

In fact, our first observation was the spring witchhazel shrub (Hamamelis vernalis) in Longenecker Horticultural Gardens. Its skinny yellow petals have popped out and were serving to attract early-emerging bees. (Fragrance helps, too.) There aren’t that many nectar and pollen sources available this early in the season. Clearly the bees had tuned in to this one.

Next we walked over to the shrub trials area because I knew that some of the early pussy willows had burst their buds. The gardens have an entire row of Salix discolor, including some color variants. The ones that are open now are the traditional gray. For pink kitties, you have to wait a bit longer.

Everybody had a chance to pet the soft fur of these cheery little harbingers of spring. Specifically, these are the male catkins—just can’t seem to get away from feline terminology here. Willows have separate male and female flowers, featured on different plants. This habit is called monoecious. Some other trees—alders come to mind—have separate male and female flowers that occur on the same plant, a condition known as dioecious. And then there’s the gambit of producing both male and female parts not only on every plant, but within each flower.  This strategy, we call perfect.

But back to pussy willows. The female catkins will appear, on different bushes, a bit later in the season. They are not as showy as the boys, being somewhat spikier in appearance, with less dense fur. Hmm, can’t help but notice that the male flowers emerge first and thus need warmer coats as a hedge against the weather? Good planning there by Ma Nature, taking care of her tender children.

The next thing I wanted to show my visitors was . . . snow fleas. Accordingly, we strolled back past the Visitor Center, passing through a bit of the Wisconsin Native Plant Garden, and into the Curtis Prairie.

There, in snowmelt puddles along the fire lane trails, you can see thousands of springtails—order Collembola—also known as snow fleas. No worries, they are not true fleas, and they do not infest humans, other animals, or buildings. Peer into a tire-track puddle: you’re likely to see small black specks floating, either individually or in large clumps. Each speck is about the size and configuration of a caraway seed. Look closer, use a hand lens, or flip your binoculars over to serve as magnifier, and you will see multiple body segments, perhaps even antennae. (Thanks to the late great naturalist Ken Wood for that latter trick.)

Not only are these fascinating little fellas not really fleas, they’re not really insects, either. They were formerly classified as such, but are currently considered “pseudo-insects,” since they have some of the attributes of insects but not others. For instance, they lack wings, and they do possess a unique structure called a ventral tube or collophore, whose function is not well understood. Scientific opinion on such issues has been known to change, and who am I, a mere naturalist, to pretend certainty?

I don’t know if anyone has ever studied the snow fleas in the Arboretum. Perhaps that is a research project waiting to happen! Kaufman’s Field Guide to the Insects of North America claims that the best-known species is Hypogastrura nivicola. (See above about certainty.)

At any rate, they overwinter in decaying plant material under the snow, and turn up in puddles when melting occurs. They can’t swim, but don’t drown, and will revive. Soon they’ll mate, and the females will lay eggs in the newly-thawed soil. And the beat goes on. . . .

Enjoying the sunshine, our group continued along the Curtis Prairie fire lane, noticing goldenrod ball galls along our way. By this time of year, quite a number of those have been drilled by hungry birds—downy woodpeckers are the ones I’ve seen personally—and the grubs inside devoured as a delicious protein snack. The galls that are still intact may produce small flies in another two months or so, which will lay eggs on new goldenrod stems and start the process all over again. Meanwhile, the plant continues its growth pattern undisturbed.

We ventured a short distance toward Teal Pond, but knowing about sloppy conditions ahead I elected to turn around at the F-1 intersection. There under the trees, we paused for a short reading from Hal Borland’s Twelve Moons of the Year about the signs of spring that may be seen in late February: reddening of red-osier dogwood; yellowing of willow twigs; early flowers and bees; sap rising in the maples, and squirrels sipping it. Several of those marvels we had indeed witnessed on our hike. Hmm, I wonder if Borland ever wrote about snow fleas?

We returned to the Visitor Center satisfied that good things can come within short distances. Happy exploring—and wear your overshoes!

—Kathy Miner

 

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