Wednesday, July 10, 2013

Ash-tree Bolete

Ground-level view of an Ash-tree Bolete cluster on a grassy trail

Mushroom species are seasonal in nature, much like wildflower species, but unlike plants, they do not require sunlight. For most of the year, they are underground or growing inside dead wood or otherwise out of sight. Rain is good for mushrooms and this year holds promise of an abundance in the Northeast, both in number of species and a surplus of each type. When mushrooms "suddenly" appear, what we see are just the fruiting bodies with the sole function of releasing spores (think evolutionary predecessors to seeds). They will drift on the wind and those that find suitable landing pads will develop into new, hidden networks underground or inside rotting logs, and these may last for years.
 

Top and bottom of Ash-tree Bolete caps.

While the familiar mushrooms have radiating gills that produce the spores on the undersurface of the caps, Boletes are a family of mushrooms (Boletaceae) that have a spongy layer of pores or tubes on the underside to do the same job. Boletes are soft, fleshy and stalked and often grow in the woods. Many of the 200 North American species are edible, but only a few are worth the effort of collecting, and several are poisonous, so beware.
 

Angular pores radiating away from the stalk at the edge of a cap.

Where do you think Ash-tree Bolete (Boletinellus merulioides) grows? (one guess) Well, true to its name, in our yard it grows on the grassy and moss-covered trails under the ash trees. Numerous brown caps, averaging three to four inches across, are growing either singly or in tight clusters. The older ones are wavy-edged and distorted. On the yellow underside of each cap, a network of irregular ridges and cross-ribs creates a fine pattern of angular, shallow pores giving this mushroom the nickname, "shallow-pore." The thin folds can appear almost gill-like as they radiate away from the off-center stalk. (Sometimes the stalk is lateral, or attached at the edge of the cap.) If bruised, the pores turn blue-green, then reddish-brown. Beware, some of the toxic Boletes are blue-staining.
 

A row of Ash-tree Boletes on a grassy trail under a grove of ash trees.

Ash-tree Bolete (also called Boletinus porosus and Gyrodon merulioides in some field guides) grows from Michigan to Eastern Canada and south to Texas and Florida. This species is edible, but not recommended, partly because of the chance of confusion with several toxic boletes. That risk aside, the quality and flavor are said to be poor, at least in comparison to better mushrooms.

It's likely a snail scraped part of the right cap to make a meal.
The left cap is turned over to show the underside pores.
Corrections, comments and questions are always welcome at northeastnaturalist@yahoo.com or connect through my Facebook page and photo page. There's also a community-type page for The Northeast Naturalist. Other nature and geology topics can be found on the parallel blogs Adirondack Naturalist and Heading Out.

1 comment:

Beatriz Moisset said...

So, I guess that it has a symbiotic mycorrhizal relationship with ash trees. So much to learn!