Text Size: A | A | A

Sharp shooters

Hawthornes have signature thorns
Buy This Photo
A young Hawthorn twig.Sue Pike

The thicket next to the stream that winds behind my house has been a busy place this winter. Otter tracks wind back and forth along the ice-bound stream, sliding into the running water through holes in the ice. Squirrels and mice bound across the snow, from tree to tree and hole to hole leaving a zipper-like trail in the soft powder. The deer have formed a number of main trails through the open places in the tangle, shouldering through the thicket, leaving strands of hair clinging to the long thorns of the spindly hawthorns.

In the summer, when there are leaves on the trees, the long thorns on the hawthorns aren't as obvious as they are now, 2 inch long spines, hard and sharp enough to draw blood, sticking out at right angles from the twigs and trunks.

Hawthorns belong to the rose family, members of the genus Crataegus. According to the University of Florida Cooperative Extension, "The word stems from the ancient Greek name Krataigos, which the Greek philosopher Theophrastus used to describe a thorny flowering plant. It is a combination of the Greek words "kratus" meaning strong, and "akakia" or "akis" meaning thorn." The name of the thorny acaicia tree that giraffes love to chew on is derived from the same Greek word.

There are a huge number of different species of hawthorn in the United States. There is some controversy as to how many species; different sources list from a couple hundred to almost 1000. Given that many of these species hybridize with each other it can be almost impossible to distinguish one from another. However it is relatively easy to identify hawthorns to the genus level (Crataegus); most members of this genus are shrubs or small trees, with long sharp thorns and small, variably-shaped leaves with sawtooth edges. The fruit is usually a cluster of bright red berries.

The fruit are sometimes called "haws," though, interestingly, the word "haw" in the name hawthorn is Old English for "hedge" because many species of hawthorn form dense, impenetrable, spiny thickets and were frequently planted as hedges. Hawthorn makes up more than 60 percent of the hedges planted following the General Enclosure Act of England in which land previously considered commonly-held land, or commons, was privatized and enclosed by thick, thorny hedges that prevented easy access by the peasants.

While the hawthorn berry is edible (though the seeds contain cyanide and should be avoided) they are not favored by wildlife, probably due to their low fat content. They are much more attractive as cover, the thorny branches providing excellent protection from predators.

According to Charles Fergus, in "Trees of New England: A Natural History," the actual adaptive significance of the thorns is somewhat unclear. While you would think that the thorns are there to protect the foliage, deer can successfully browse by feeding between the spines.

Ecologist Don Janzen theorized that, since the thorns are spaced too far apart to deter modern browsers, they might have evolved to thwart larger mammals, the megafauna such as ground sloths that lived in North America up until the start of the Pleistocene.

Apparently the hawthorns haven't yet figured out that their predators are long gone.

Sue Pike, a researcher and an environmental sciences and biology teacher at St. Thomas Aquinas High School, welcomes your ideas for future column topics. She may be reached at spike3116@gmail.com or via her blog, sp.stalux.org.

Reader Reaction
New Careers & Jobs
Hot Properties
Subscriber Rewards
Ads by Google