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Winter Mushrooms of the Diablo Region

Updated: Jun 12, 2023

Winter Mushrooms: The Rainbow Season

Spring is almost here yet the San Francisco Bay Area’s common winter mushrooms are just making their appearance. As I mentioned in my fall fungi column, our mushroom season began very late this year; mushrooms we expected to see in October didn’t appear until mid to late December.

Many of us are familiar with spotting mushrooms in the traditional toadstool-esque cap-and-stalk form, so training the eye to see other fungal varieties can take some practice. That said, once one has keyed into the weird and wild appearances of other fungi, different species really start to catch the eye. Here’s a sampling of what to look for right now:

“Cup fungi,” which are late-fall through winter mushrooms, are exceptionally curious and yet so often overlooked. As their name suggests, these mushrooms grow in the shape of cups – though sometimes wrinkled or misshapen – and in a lively variety of colors. I like to think of them as little bowls, yawns, ears, or satellites growing from the earth. If you want to find cup fungi, try checking under sodden branches and in leaf litter, in dark places near creeks, under conifers, or in wood chips.

While the typical toadstool disperses its spores downward through parallel gills or cylindrical tubes that are attached to the underside of the cap, cup fungi can be thought of as inverted mushroom caps that expel their spores upward and out of the cup. These mushrooms store their spores within specialized cells along the cup’s surface known as “asci” (plural, or “ascus,” singular). Fungi with asci are known as Ascomycetes.

When the spores of an ascomycete become mature, the asci of the fungi begin to absorb water, thereby building internal pressure. At mid-maturity that pressure becomes extreme. If the fungi are disturbed in any way, their asci rupture all at once causing the spores to forcibly eject and puff dramatically from the cup. This is a phenomenon called “sporulation” – the method by which fungi and a variety of other organisms release spores for reproduction. When a heavy wind picks up, or rain droplets splash into the cups, spores are dispersed into the air.

To see footage of this fascinating phenomenon, please visit my blog about sporulation which I’ve included at the bottom of this post. For each of the cup fungi I will discuss below, there is a sporulation video.

Scarlet Elf cups (Sarcoscypha coccinea) are one of the most common and striking of the cup fungi. Growing in a vibrant hot pink, these mushrooms cling to decaying wood, often just at the surface of the soil. With a diameter anywhere from 1 centimeter to 4 inches, these fungi love water and seem to pop up alone or in large clusters near creeks and moist forested areas as soon as the climate becomes adequately cool and moist.

Orange Peel Cups (Aleuria aurantia) Aptly named, these neon-orange cups grow around 1 centimeter to 3 inches in diameter, in moist areas on soil, alone or in clusters. (Once you have spotted one, you will also start noticing the plethora of orange peels that people discard along trails.)

Ebony Cups (Pseudoplectania nigrella) are particularly elusive being that their midnight-back color blends in easily with the moist soil and downed logs they grow against. Growing between 1 – 2 inches wide, these too are often found on shaded hillsides, alone or in clusters, and among moss.

Palamino Cup (Peziza repanda) is one of the most common of the cup fungi. Appearing in light-brown, thin, and somewhat brittle to the touch, these mushrooms grow on a variety of substrates from mid-fall through winter on a variety of substrates including under conifers, in leaf debris, along hillsides, or in wood chips. For cup fungi, Palamino cups can grow rather large – sometimes over 5 inches across.

Another particularly vibrant group of common winter mushrooms are the “Waxcaps.” The waxcaps have a cap and stem, and grow in a spectacularly diverse variety of colors and species. A personal favorite, the glossy tops of these brilliantly colored fungi almost glimmer like jewels scattered along the forest floor. Waxcaps often appear so shiny that they catch the reflection of the trees above them. Even when compared to other colorful fungi, these mushrooms really stand out.

Waxcaps require colder temperatures in order to fruit, thus they are not common until moisture and low temperatures are present. Soil-dwelling fungi, waxcaps are found growing under conifers, particularly redwoods. Interestingly, waxcaps often grow in fields in Europe, while in North America they are associated with woodland areas, cool temperatures, and lots of moisture. This continues to stump scientists who still don’t know why there is such a considerable difference in preferred habitat.

Waxcaps can fairly easily be categorized by color:

Red/Orange: “Cherry Waxcap” or “Scarlet Waxcap” (Hygrocybe species). These glistening red waxcaps with bright yellow stems are striking against the dark browns and greens of the forest, so they are very easy to pick out. While there are quite a few similar-looking red waxcaps, and deciphering a specific species can be difficult, it is easy to pick out the genus as there are no look-alikes outside of Hyrgrocybe species’.

Yellow: “Golden Waxcap” (Hygrocybe flavescens). Characterized by their stunning yellow tones, often have large caps of 2-3” in diameter.

Appearing in green/teal (and pink and orange and sometimes even purple!) is my personal favorite: the “Parrot Waxcap” (Gliophorus psittacinus). These are among the only fungi that are capable of growing in a significant variety of colors. Often beginning their lifespan in shades of green or teal, as they age, parrot mushrooms grow into shades of oranges and pinks. This range of colors has earned the mushroom the moniker of “parrot” – both the bird and the mushroom show off a stunning rainbow of colors.

One final mushroom that is rather easy to distinguish is the “Questionable Stropharia.” This mushroom is bold, takes up space, and is most easily identified by the lacy off-white “skirt” that hugs the perimeter of a chunky, banana-yellow cap. It has a thick, bulky stalk, and can grow several inches tall, eventually toppling under its own weight. Found alone under conifers, or scattered in groups, Stropharia prefer coastal forests in damp, shaded areas.

Having mentioned that Questionable Stropharia mushrooms are easy to identify, the irony in the following is not lost on me: I overheard at a mycological lecture a few years ago that the reason these mushrooms are called “Questionable” is because this particular species is capable of growing in different – though very similar – forms. I am reminded of the parrot mushroom which is quite similar – growing in different colors within the same species.

At this time there are many fascinating mushrooms out there to be found – and the colors are especially at their peak. I recommend looking in cool, moist, wooded areas, and taking your time. Be mindful of your surroundings and look closely. Keep in mind that certain mushrooms only grow under certain trees or areas. For example, waxcaps prefer redwoods. Where you search determines what you find. Keep looking, be respectful, and have fun. You are bound to come across something!


As a very brief follow-up to my column on Fall Mushrooms, I am including this photo. I had discussed how mushrooms are the reproductive organs of the actual fungus that lives below ground (or within decaying matter) in the form of fungal roots. These roots, referred to as “mycelium,” appear as white threads – seen clearly in this photo which I took a few weeks ago.

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