Field Guide to Mushrooms of Western North America

1. Introduction

Of the lower 48 states, those in the West have the most diverse landscape. Within their borders lie the tallest mountain (Mt. Whitney at 14,494 feet) and the lowest point (Death Valley at 282 feet below sea level). There are rain forests, deserts, volcanoes, foothills and valleys, and thousands of miles of coastline. This variation affects the types of mushrooms found and the timing of their appearance. Fall and winter are the best seasons for mushroom hunting along the coast and in the foothills. Mushroom clubs in the Pacific Northwest and in northern California often schedule their coastal forays October through January, months when the high mountains are snow-covered, with no hint of fungi except for the occasional tree conk. High elevations are productive for fungi after snowmelt in late spring, although fall can be productive when there is rain and no frost. The Rockies and high mountains in Arizona can be very productive in late August following monsoon rains. Spring is morel season in much of the West. Inland valleys are not as productive for fungi as coastal areas but mushrooms can be found in many locations during the rainy season and on watered lawns throughout the year.

Fig. 1 Photo of Morchella elata

Individual species of mushrooms are typically associated with specific habitats. The Black Morel, Morchella elata, sometimes fruits in large numbers in montane forests the year following a forest fire.

Uncertainty is an attraction of mushroom collecting. Fruiting is predictable but never certain. Unless you have seen something a few days earlier with your own eyes, you can never be sure of what is in the field at a given time. Mushroom fruiting depends on the alignment of season, temperature, and moisture. If any of these factors is unfavorable, fungi will be sparse or non-existent. If there has been no moisture during the mushroom season, mushrooms are not likely to fruit that entire year. An early frost may have a similar effect.

Moisture is less of an issue for foragers along the fog-shrouded coast, but for those who seek mushrooms inland or in the Southwest where there are two seasons- dry and wet- mushroom hunting for much of the year is restricted to irrigated orchards, lawns, and gardens. There is also the matter of access, which is more of a problem in some locations than in others. Private land may be posted with No Trespassing signs, and park land is often off-limits. Most National Forests are open to non-commercial foraging but may require a permit. Some mushroom clubs have made special arrangements with a local agency to allow picking. If you are willing to pay a fee, there are organized forays on private land, typically with meals and overnight accommodations nearby. These proprietary forays are advertised in mushroom periodicals and club newsletters. Contact information for mushroom clubs and organizations is found in Section 11 (Resources).