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Stebbins Cold Canyon Reserve

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The Fungi of Stebbins 
Cold Canyon Reserve
(by Bob and Barbara Sommer)

Click here to view a number of mushrooms.

     Valley and foothill fungi appear mostly during the all-too-brief interval between fall rains and winter frost. The dry summer soil requires several rains before fungi appear (one rain does not a mushroom make). Once the temperature dips below freezing, the mushrooms disappear, and only those under a layer of duff are likely to remain intact. The Reserve cannot compete with the fog-shrouded coastal forests with their mild temperature in regard to fungi. 
     Fruiting of mushrooms depends on rainfall, temperature, and season. The most abundant times are December and January which are the peak rainfall months. Records at Winters, CA about seven miles east of the Reserve, based on the period 1943-1982, show an average of approximately 4.1 and 4.7 inches of rain in December and January, respectively. However, temperature also plays a factor, and December and January are also the coldest months at the Reserve, bringing the likelihood of low temperatures which inhibit mushroom growth and freeze the fruiting bodies of those above ground. The ideal conditions for mushrooms in the Cold Canyon Reserve are an early mild, wet winter. The mushroom season is brief, two months under good circumstances and less in a cold, dry year. 
     There is a predictable cycle of mushroom fruiting starting with the LBMs (little brown mushrooms) after the fall rains. LBM is a generic name for small, undistinguished gilled mushrooms that are typically brown, black, gray, or white. The genera include Mycena, Paneolus, Marasmius, and Collybia species. What these mushrooms lack in size, color, and distinctiveness, they make up for in numbers. Some sections alongside the trail will be carpeted with LBMs. 
     After this come the hardy Earthstars (Geastrum triplex) and the underground fungi, sometimes called False Truffles, which are protected against all but the most severe frosts. The most common underground fungus we have observed is Rhizopogon occidentalis, an attractive, white fungus whose flesh turns red when handled, with a pleasant odor, and of unknown edibility. It is much valued by rodent species who dig it up in the cold months when other food is scarce. Humans can use the telltale signs of rodent excavation to locate underground fungi.
     What happens next depends on the amount of rain. If it is a dry year, there may be no significant fruitings of large fleshy fungi. If rains continue during the winter months, fruiting can be impressive in number of fungi, although not necessarily in variety of species or in the availability of choice edibles. The only highly regarded edible fungi we have seen at the Reserve are the Matusutake (Armillaria ponderosa) and the morel (Morchella semilibera). There are other edible fungi on the Reserve, including meadow mushrooms (Agaricus campestris) and the slippery jack (Suillus pungens) but these can be found in other locations in greater quantities.
     One of the attractions of mushroom hunting is the surprise and mystery surrounding the appearance of fungi. You can think that conditions at the Reserve should be ideal in terms of moisture, temperature, and season and still find nothing except LBMs. The next visit may produce an array of fungi in all colors and sizes. Ten years of following fungi at Stebbins Reserve has not provided certain clues as to their appearance. We can state with certainty that there will be no significant terrestrial fungi during the hot dry summer months or when winter temperatures dip below freezing. There will also be a delay in the appearance of fungi when the rain season begins. It will require two or three significant rains before tiny mushrooms appear in the leaf litter, another rain or two before the intermediate-size mushrooms are seen, and another rain or two before the major fungi make an appearance. This sequence can be interrupted or aborted at any time by a major freeze.
     The mushroom list comprises the mushrooms observed between 1985-96 with links to photos of many mushrooms. Fungi are listed according to genus and species in alphabetical order. December and January are the peak months for fruiting, especially for Hygrocybe and Lactarius species. Hygrocybes are brightly colored, attractive, small fungi known for their waxy gills and the Lactarius species tend to have more subdued earth tones and the interesting characteristic of exuding latex when the gills or flesh is cut.
     Tree fungi, apart from common small species such as Trametes versicolor and Schizophyllum spp. which occur on fallen limbs and stumps, are poorly represented at the Reserve. We have not found the large polypores associated with riparian habitats in other parts of the foothills, some of which have been collected for food by local residents for many generations.
     February mushrooms are generally the latecomers of the season, representing additional fruiting of winter species rather than new species associated with spring. A visit in February 1988 following ample rainfall, showed many Lactarius and Hygrocybe, but both of these genera had been more common two weeks earlier, and many of the specimens seen in February had passed their prime. Unless there are heavy spring rains, a reasonably comprehensive picture of significant mushrooms can be obtained in visits during December and January. 
     Heavy rains in February and March can bring spring fungi. In 1989, the combination of heavy March rains and the previous year's burn, brought an abundance of spring mushrooms associated with charred ground, such as the tiny orange cup (Anthracobia melaloma) which were also seen in abundance following the 1995 floods, early morels (Verpa conica), and true morels (Morchella semilibera). Summer rains are uncommon in the Central Valley (and would be an economic disaster for many local farmers), but they could produce mushroom fruitings not shown in the mushroom list.

For more mushroom images see the mushroom list or the thumbnail page.

Last Updated 03/09/06