The Urban Pantheist

It's that time of year, where even my denial of the fact of autumn must fall away like so many beautiful sugar maple leaves.


One of the supposed advantages of using honey locust for street trees is their tiny leaflets easily blow away, not accumulating on the sidewalk. Um. Sure is pretty though.


Another day, another group of wine caps. The "rough ring" that they are named for (rugosoannulata) has fallen off each of these mushrooms. Never rely on only one field marking for identification, they say.

Honeylocust at the edge of the Franklin Park golf course.


My view as I left work this afternoon.

Reishi Ganoderma lucidum


Identifying mushrooms is difficult, perhaps I've mentioned that before. Many species look similar to one another, and many field markings are variable. In G. lucidum what appears to be a bracket fungus, growing directly from a tree here, can have a long stalk. It can be relatively more red, or banded like a candy corn, or more white. It can be broad and fan-like, or narrow and branched like antlers. All of this would be mere curiosity for naturalists if this mushroom wasn't among the most important medicinal fungi in traditional Asian medicine.

The shape and perhaps the color, as well as other attributes are thought to enhance one property or another. Fortunately scientists are starting to look into it, and are finding anti-tumor and other protective qualities. Whether the shape of the mushroom influences its ability to cure disease is not known, but it is known that the shape is influenced by the conditions of the mushroom's growth. Longer reishi mushrooms and stalked fan-like brackets tend to be produced in warmer areas. In Boston we tend to see stalkless brackets on trees and misshapen blobs growing from hidden roots. One of these latter mushrooms was treated with great suspicion in New York City recently. Hacked from its spot where it was growing on subterranean Callery pear roots, it grew back; well, of course it did--removing the fruiting body does practically nothing to the fungus that produced it.

Reishi (I'm using the Japanese name because it is short and easy to say) can be a beautiful and durable mushroom. If you don't grind it up for tea you can dry it and keep it as an ornament. It readily grows in cultivation and you can buy kits to do so. (You can also buy capsuled reishi supplements and even reishi-infused chocolates.) In North America, a close relative G. tsugae grows from conifers. DNA research seems to indicate that the two North American species are closer related to one another than they are to the G. lucidum that grows in Asia. The above specimens are growing from a larger burl on a honey locust tree that has appeared in this journal (here) before. I posted a very different photo of mushrooms from this species complex here.

Honey locust.

Honey locust pods.

Pretty bleak out there yesterday. I started walking Charlie along the Muddy, and just got disappointed by how cold and colorless and ugly it looked. That's probably a reflection of something inside me rather than an accurate depiction of the park. So I left the Riverway and went behind the apartment buildings that border it, but are separated by the trolley tracks. Still pretty colorless, but at least there were some things I hadn't taken pictures of before. As nasty as it was out, I'm thankful to be spared the two feet of snow that other places got.

Just heard a snippet of a Robert Krulwich piece on NPR that made me dash to the computer to check out the full story.

One of the guaranteed species on an Urban Nature Walk is the honey locust. It's a widely planted, pollution tolerant tree, with tiny leaflets that blow away in the fall requiring little clean-up. Most of the honey locusts found in cities are cultivated varieties that have done away with their two most interesting features. First, their huge seed pods, and second, their array of large sharp thorns:



I'd been walking around with the misapprehension that this tree was native to the hills south and west of here, but apparently that applies only to black locust.  Honey locust is considered native, and for the purposes of Krulwich's piece, was known to be growing on Manhattan Island 13,000 years ago.  Also on Manhattan at that time, were elephants, specifically mastodons.  Now for the honey locust tree to evolve these big, sharp, and expensive (from a biological point of view--that's a lot of energy to devote to a decoration) thorns, there had to be some animal that the tree wanted to deter.  I always assumed that the thorns were there to slow down raccoons and bears from climbing the tree to eat the seed pods before they were ready.  Krulwich proposes that the thorns, which come out of the bark of the trunk as well as the branches, evolved to keep some herbivore from stripping the bark.  He points out that the acacia tree of Africa, which famously still has elephants, bears similar thorns.  He also mentions that until someone studies mastodon droppings or coprolites and finds honey locust parts therein, there is no proof that mastodons ate from the honey locust.

Pretty cool.  Of course my contrary side would quickly like to mention that there are other bark-eating animals in Northeastern North America that haven't gone extinct.  Moose and white-tailed deer come to mind, not to mention the cottontails.  But it's so fun to picture mastodons in New York and New England that I'll play along for a while.

Photo by urbpan. A planted row of honey locusts along a parking lot in the Fenway.

Urban species #271: Honey locust Gleditsia triacanthos
See also black locust

If you closed your eyes in Boston, and touched the first tree you found, the chances are very good that you would touch a honey locust. Fortunately, honey locusts chosen for urban plantings have been cultivated so that they lack the huge sharp thorns that their wild equivalents have, so you could touch it safely. Honey locusts are one of the the top five or six tree species planted in Boston. In Manhattan and Chicago, honey locust is number one.

When, in the Appalachians, land was cleared of trees and scarred with mines, the first wild tree to regrow in the area was honey locust. Its ability to grow quickly in damaged areas suggested that it would be a good choice for the city. Indeed, it's a pioneer plant that tolerates a wide range of disturbed soil qualities, including typical urban soils--compacted by traffic, depleted of nutrients, tainted by pollutants.
Honey locust's foliage is a selling point as well. The leaves are composed of dozens of very small leaflets, which filter sunlight to create a dappled shade. And when the leaves fall in autumn, the leaflets tend to blow away in the wind, rather than accumulate into heavy litter.

But sometimes some litter piles up around the tree anyway. Honey locust is a legume, and its seeds are borne in large shiny brown pods. Often city dwellers will encounter these pods on the sidewalk, not understanding where they came from. Unless there are still some clinging to the small spindly tree's branches, it's hard to associate the fruits with the tree. Each pod has several seeds inside, and when the fruit is mature, the seeds rattle loosely when it's shaken, like a flattened maraca. When the fruit is still green, the seeds are held in a sweet gummy sap, giving the tree its name. There are cultivated varieties of honey locust, engineered for tidy landscapers, that produce no seeds at all.


A honey locust pod changing from green to brown as it matures.

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