Entoloma abortivum: a mushroom parasite

One of the first mushrooms I learned to identify was Entoloma abortivum.  It is readily recognized because the typical mushrooms — with a stalk and a cap — are accompanied by aborted (hence the species name) mushrooms. The aborted masses are white and up to 3″ in diameter.

The aborted mushrooms are variously known as  ‘ground prunes,’ hunter’s heart,’ ‘shrimp of the woods,’ and, in Mexico, totlcoxcatl.  Back then, in the late sixties, we thought  that the aborted masses were an expression of the Entoloma mushroom, but in the mid 1970’s it was determined that two mushroom fungi are involved. Later it was determined that the Entoloma was parasitizing another mushroom, a species of Armillaria — the tree parasite called ‘honey  mushroom’ that is always found on wood long after the tree-host is dead.

Armillaria mellea, the honey mushroom
Armillaria mellea, the honey mushroom

The Entoloma is a decomposer. It breaks down litter in the forest and it is not mycorrhizal with trees or other plants. At least around Deering the Armillaria is more common than the Entoloma.



The Entoloma is one of the ‘pink spored’ mushrooms. It occurs on  soil, and its gills are decurrent (that is, they run down the stalk from the cap).

There is a literature about the edibility of this mushroom. Both the Entoloma and the Armillaria are edible. However, I will only emphasize that some of the pink-spored Entoloma species are toxic, and some species that have brown spores(Pholiota species) look like honey mushroom but are also toxic.

The only  constant rule with mushroom hunting is: never eat what you do not know for 100% certain.

You can read more about Entoloma abortivum at:


For me, the interrelationship of these two mushrooms is one of the fascinating stories that we find in our forests.  Finding Entoloma abortivum after all these years is a treat for me.


First, allow me to orient you with a little bit of Mycology 101. Specifically two basic sorts of mushrooms.

The mushroom is the result of sexual reproduction. The process? Not sexy. A couple of nuclei get together in a special cell and the process cascades: nuclear fusion and meiosis —  where basically the genes get sorted — and finally a spore containing the recombined genes forms. What you see in a mushroom is the launching platform for the spore. The spores of all mushrooms are born externally on specialized cells. How and where those cells are placed distinguishes two major groups of mushrooms.

In one group the cells line thin sheets, or gills. So, if you look on the underside of the cap of one of these mushrooms you see the edges of a lot of gills radiating from the center, the stalk. The common supermarket mushroom is one of these, so is matsutake.

In another group of mushrooms the cells that bear the spores form inside tubes. If you look on the underside of one of these mushrooms you will see tiny pores. These are colloquially called boletes and the most famous bolete is the Cep.

This story is about one kind of bolete.

Many boletes and other gilled mushrooms form associations with the roots of trees and other plants to share nutrients — called mycorrhizae. It’s a  mutualism wherein all partners get — and give — something. Some people think that the fungus body,  filaments radiating through the substratum that you never see, connect trees and mushrooms in a kind of messaging system. These are good guys.

The ash-tree bolete — Boletinellus merulioides — is not a good guy.

At least not good for the ash trees.

Boletinellus merulioides is not mycorrhizal. It is in a symbiotic relationship with the ‘leafcurl ash aphid’ or ‘wooly ash aphid,’ Meliarhizophagus fraxinifolii. An ash pathogen.

This aphid has a complicated life, but it is inextricably tied up with several species of ash trees. Eggs, which overwinter in laid in cracks of the bark, hatch in the spring. After hatching, the aphids feed first on shoots, and then a new generation feeds on newly developing ash leaves. The leaves become distorted and ultimately form ‘pseudogalls,’ within which there is another generation of aphids. Eventually, as early as August, some of those aphids fly off and lay eggs. During summer  some of the females change their behavior. They begin to feed on roots of ash trees. A new generation of males and females develops from those root-feeding aphids to complete the cycle.

But some of the root population remains in the soil all year, feeding on roots. They form a symbiotic relationship with the ash-tree bolete.  The mushroom’s mycelium protects  aphid by producing little knots of tissue around them. In return the honeydew produced by the aphid nourishes the bolete.

The ash ash aphid is native to North America but it has become a problem on European ash trees.


Black Swallow wort: a nasty invasive in our zip code!

A bunch of invading plants that no walls can keep out are living in our town of Deering, a small rural community located in south central New Hampshire/the  Monadnock Region,.

We have been successful thanks to a Lake Hosts boat inspection program and an active group of Weed Watchers, in preventing the introduction of highly invasive Variable Milfoil into our lake, and — unlike most towns in our area — Japanese Knotweed is not a conspicuous feature of our roadsides because members of the Conservation Commission  cut the stuff back each year.

But this year I am noticing a whole lot of black swallow wort in town. This plant — Cynanchium louisiae — is disastrously invasive. It grows thickly on the ground and quickly covers everything, preventing the growth of other plants. Even covering street signs! Like all successful invasive species, black swallow wort has no local  parasites or browsers to limit its development. And, like milkweed, the seed come out of the pods in a fluff that is easily scattered by wind.

There is a dense growth of this invasive in the Tom Rush meadows, but few go up there to see it. Where it is most conspicuous is along roadsides, probably in front of your own home. Lurking in rock walls or around your mail box.

Black swallow wort is a native of Europe that was introduced into the United States, through Massachusetts, in the mid 19th Century. The plant is widely distributed in eastern USA and Canada but is not common west of the Mississippi River. A second swallow wort, Cynanchum rossicum, was introduced into New England from Europe as an ornamental late in the 19th Century. Its distribution is limited to the New England states. I have not seen it in Deering.

Black swallow wort is easily recognized. It’s a low growing herb with dark green leaves; the plant tends to vine. The leaves are paired, opposite each other on the stem, narrowly heart-shaped, and drawn to a fine point. The have a strongly developed central vein that causes the halves of the leaf blade to form a kind of V-shape down the length of the leaf. Flowers form at the tips of the vine and are small, dark purple. Kind of pretty actually. The fruit is a twin capsule. The roots are white and thick, forming a mat in the soil; there can be a tap root.

Apart from its invasive nature, black swallow wort and other swallow worts, which are related to milkweed, are toxic to Monarch butterflies, deer and cattle. The plants themselves contain the toxin, and they put toxins into the soil that prevents  growth of other plants.

We all know by now that milkweed is the preferred medium for development of Monarch butterflies. The butterflies mate, most famously in Mexico, but in other western sites as well. They then migrate north and east looking for a place to lay their eggs. In March and April they lay their eggs on milkweed and, lamentably, black swallow wort .  About two days later the eggs hatch to the distinctive caterpillar, which feeds on milkweed.

However Monarch caterpillars that hatch on swallow worts are not able to feed. They avoid the toxin in the plants, and thus do not survive. From an ecological point of view, they are wasted.

After two weeks, the caterpillars on attach themselves to a stem or leaf of milkweed and begin the process of metamorphosis that leads to the beautiful Monarch butterfly.  The emergent butterfly will fly away to enjoy about two weeks of feeding on all sorts of flowers but, just before dying, they lay their eggs.


Clearly, black swallow wort is a bad actor. But you can help to control it.

Cutting it back is not good because that will only encourage more growth. Most of what I see in town along roadsides can maybe controlled by digging. You can dig it out, but dig deeply so as to get as much root as possible. You will have to return and dig out what you have missed but eventually . Glyphosate is effective.


It is impossible not to notice shrubs with white flowers growing alongside Deering’s roads in the spring.

I know of three species that are more or less common, all of which are native to Eastern North America, extending from New Brunswick to  the Gulf states.

The most common, and conspicuous, of Deering’s flowering roadside shrubs is hobblebush, Viburnum lantanoides.

Hobblebush inhabits the understory of cool forests. It produces flat-topped clusters of white fowers in two forms: 1) an outer ring of 3/4-inch wide, showy white flowers that are sterile, but may attract pollinators; and 2) an inner cluster of small greenish, fertile flowers. This shrub is a host plant for the caterpillars of the spring azure butterfly (Celastrina ladon). [from Native Plant Trust Go Botany]. Clusters of red berries form late in the summer.

Hobblebush grows densely in the understory. If you have ever tried to ‘bushwhack’ through a patch, you would understand and appreciate the aptness of its name, hobblebush.

Chokeberry and serviceberry are easily distinguished from hobblebush at 40 mph, but you will have to slow — to a stop — and get out of your vehicle to determine which of these the small-flowered , spindly-trunked bush is.

Eastern shadbush, Amelanchier canadensis,  is a 6-20 foot (2-6.5m) tall tree that produces white flowers in March and sweet, edible berries in June (around the same time as the annual shad run in New England). The smooth, light grayish-brown bark has vertical dark stripes.

With a graceful, arching growth form that resembles alder, as well as reddish fall color to the leaves and edible fruits, this species makes a pleasant backdrop planting for the garden. [from Native Plant Trust Go Botany].

Black chokeberry, Aronia melanocarpa, is also a small tree, similar in stature to eastern shadbush and, like shadbush, is a member of the rose family.

I have only seen black chokeberry  in the wetlands of  Deering’s Longwood Road. I am not 100% certain that this is A. melanocarpa because I have not yet seen its fruit.





It is said that the ‘pink earth lichen,’ Dibaeis beomyces, can be identified from a car at 40 miles per hour.

Dibaeis beomyces on a roadside

I don’t know about that. But, this lichen is distinctive for its cushion-shaped, pink caps that top short, pale stalks.  The pink cap is where the sexual spores form. They are spread by water splashing. The stalks arise from a thin crust, the crustose thallus, where cells of the photobiont — the green algal partner of this lichen — are found.

Dibaeis beomyces occurs on clay soils, often on road banks, and that is where these photos were taken.  The species has a wide northern distribution in Eastern and North America, Europe and Arctic regions generally.



Yesterday – a mid March yesterday in New Hampshire – I planned to make my (semi) regular morning walk. Usually I walk along the road and back, a distance of 2 miles. but yesterday I decided to put on the spikes and tramp through the snow we’d had a few days earlier up to the Hedgehog Mountain Overlook.

The day started out cold, near 25 degrees. The surface of the snow had frozen overnight creating a shining crust and an audible crunch as I walked.Shards of crust, dislodged by my size 14’s, skittered along in front of me. While, because of the depth of the snow, snowshoes might have been the preferred footwear, the back edge of the snowshoes was likely to have caught on the crust, causing me to tip forward onto my face. If you have ever tried to right yourself after falling while wearing snowshoes you might understand that I was just as happy not to be wearing them.


Thick snow on rock walls.

The forest was quiet. I was alone. A perfect combination. The bright sun cast long shadows of trees and their branches on the smooth white crusty surface of the snow: intersecting black lines, crossed without any obvious design or purpose but from pure joy of a glorious day. Animal tracks, made a day or so earlier, had been dimmed by melting but the game of guessing which animal had passed that way was fun.  The display was all mine.

Footsteps through snow.
A bright sun casts long shadows. Intersecting lines on the smooth crust of the snow.

The trail to the overlook first crosses Manselville Brook which, following the recent snow, was completely hidden by snow. Just last year, during the early drought, water was barely passing along on its way to the Contoocook river to the north. Now I knew that there was a steady flow beneath the snow and, hopefully, we will have a good soaking to keep the Manselville flowing through the year.

Further along, the trail crosses a small, unnamed stream that also flows to the  Contoocook. The little stream was running quite happily, and I could imagine that even now, with the cold, ‘things’ were happening in the soil through which the stream flows.

An unnamed stream. Things cooking in there, getting ready for Spring!

The trail to the Overlook is not very long, but it is, in part, steep and follows through a stream bed. When there is no snow, going is slowed a bit because of the need to pick one’s way over the rocks in the steam bed. But, yesterday all this was filled in with snow, and I could follow in the old footsteps without worrying about tripping over boulders.

A hole in the snow. Is anybody down there?

I have walked on this trail many times over the past several years. It is a part of my ‘backyard,’ so close is it to home. This year, though, I have slowed. It is no longer as easy to climb up there as a few years ago. Could I be ageing? What I do know is that now while hiking, I set goals: that tree, a trail marker, something 20 or 30 yards uphill. Just get to that point, and maybe a little beyond, and I can take a breather. Lean on my stick and take stock of where I am. I hope this is transient, this weakness, this being out of breath-ness. What I do know is that even though I know that the climb will be taxing, the payoff of being on the summit, at the outlook, makes all the puffing and associated butt-dragging worthwhile.

I love to sit on the rocks at the overlook and – – look over. It is peaceful there.


The view is grand.

Cars beetle along Rt 9, across the Contoocook River, and along airport road. Sometimes one can see a small plane taking off or landing at our airport. Whatever their goal or task, or business it is not mine. Whether the drivers are crabby or grim, it is not my worry. I am on my own time and that is time under the sun, sitting on a rock and being perfectly happy.

Just below the summit is the McAlister conservation easesment. A large block of land set aside for conservation — perpetual protection — by the McAlister family several years ago. A large part of the easement comprises a working farm bounded by the Contoocook River, where beef cattle graze. I know the farmer a bit and I respect him and his farming. No cows grazing now. The pasture is covered by snow and as the season advances, the snow melts and the river rises, part of the farm will become a lake. Part of the cycle. It comforts me to know that this working farm is preserved and I am thankful for those folks who made the conservation of this, and other lands in our town, possible.

Further, to the southwest, stands Mt Monadnock — our own monadnock, the original monadnock that gave its name to those isolated mountains that so strongly influences local weather, wherever they might be. Mt Monadnock dominates our southwestern sky line, a sign of home.

By the  time I began my descent, the day had progressed. It was nearly eleven and the temperature had climbed. Still skittles of icy crust raced before me as I moved down the trail, but snow had softened. It was clumping on the spikes making my feet heavy, each step more difficult. Footing was more difficult and at times I walked with my legs spread widely, a drunken sailor dance – – or the lurch of the subway rider. Might have made an amusing show from behind.  But, there was nobody to record it.

The trail dropped below in front of me. Carefully, step by step downward. Through – or over – the stream bed.  Still my tracks the only recent ones but leading me home. I suppose this will be the last snow hike of the season. I hope so. Soon the evergreen ferns will emerge from the snow, then tree buds. And then the full-on craziness of Spring.

I’m ready.