FUNGI

Some backyard fungi

Even if your yard is all lawn, weedy or uniform,  look  for mushrooms, especially after rains.  If you live where the snow flies, don’t bother in the cold season.  But when it’s mild and wet in full sun or shade, or even where it’s dry and sandy, mushrooms will sooner or later spring up even in a postage stamp yard (well, not literally!). And if there are trees in or adjacent to the yard, there may be even more species.  Photos below show some that have appeared in our central Florida yard. There’s no shortage of species that  appear throughout most of the American continent including well into Canada.  In fact mushrooms occur nearly everywhere even in harsh deserts.  Mushrooms are the phase of the fungal life cycle that produce spores- tiny microscopic bodies which are released in huge numbers from each mushroom.  Mushrooms are often distinctive enough to easily assign  them to species or at least genus  but often microscopic examination of spores is needed for identification.
Most of the life of most mushrooms is in the form which we cannot  see  without poking around in the leaf litter, under bark or in dead wood. Doing this can reveal  a whitish filamentous mass called a mycelium. Typically, the mycelium lives much longer than the “fruiting body” we call a mushroom but really differ little between species.  It’s the mycelial stage, however, that is performing important ecological functions as seen in the mycorrhizal and saprophytic species (see below).  In passing I would note that  fungi are neither plant not animal- they are Fungi, an entire kingdom of their own. All species producing mushrooms  are fungi but not all fungi are mushroom producers. In fact, a large number are not but  unless they turn up in my yard in some form they may get “short shrift”  despite being biologically and economically very important.
Mycorrhizal Fungi

Mycorrhizal fungi are ancient plant mutualists, i.e.  they are engaged in a mutually beneficial physiological relationship with plants, and have been for eons.  The mycelia (see above) grow in close contact with plant roots, often fully enveloping them.   The mycelia absorb minerals like phosphorous and nitrate from the surrounding soil which become available to the “host” plant ( usually a tree or shrub) and in exchange obtain  organic carbon which the fungi then metabolizes for energy.  The carbon can be traced back to the host’s foliage which has converted atmospheric carbon dioxide to organic carbon compounds by means of photosynthesis.  Mycorrhizal fungi  are widespread and form associations with most terrestrial plants . One estimate is that perhaps 80% of all vascular plant species are mutually involved with mycorrhizal fungi!  These fungi enable plants to colonize nutrient-poor soils that would otherwise be less favorable for plant growth.  Most of our crops also benefit from mycorrhizal fungi thus incorporating  land areas into cultivation that would be otherwise inadequate for human food production. Interestingly mycorrhizal fungi generally do not occur independently of host plants and in fact, some are found only in association with a single tree species.

Mycorrhizal fungi produce basidiomata (“mushrooms”, cap (pileus), or fruiting bodies) like some other kinds of fungus. These can be found in walks through the woods or even in yards and fields. Some species are edible while  others are poisonous to humans.

Saprophytic Fungi

This group of fungi inconspicuously carries out the vital function of  recycling of nutrients through the decay of  wood and other plant tissues. Here is a photograph of a colony of Armillaria tabescens.  a gilled mushroom  that sprang from an expansive growth of mycelia that sprang from underground roots of a red maple in our back yard.  Unfortunately for the maple, the mushroom is an aggressive invader of living and dead trees, and can be an important agent in the decline and mortality of forest trees. In cases where the fungus attacks living trees, they would be designated as parasitic rather than saprophytic.  The host tree (not visible) is in decline, with dead main branches, a well-thinned canopy and  sloughed-off bark at base.  Downy and Red-bellied Woodpeckers are frequent visitors and the former species successively (and exhaustively) excavated a nest-hole in a secondary (dead) branch. The tree has hosted multiple colonies of  A. tabescens for at least 5 years, but likely was under siege via root-rot, for longer.

Other fungi such as the oyster mushroom (photo) have  advertised their presence through their mushrooms but only the Armillaria   ‘root-rot’  has appeared predictably every year.  The Armillaria colonies occur mostly in autumn,  quickly passing through the above-ground phase in 1 to 2  weeks, first  seen in a small  “button” phase (photo), although undoubtedly close inspection (hands and knees) would have revealed even smaller phases.  Several days later the  button stage has expanded into  fully opened nearly flat caps with exposed gills lining the underside of the cap.  Along the gill surfaced are lined countless small spore bearing.

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