Caps

There is a tremendous amount of information you can get about a mushroom just from its cap. And this is a great thing, as the cap is typically the first thing you see when you come across a mushroom!

The diagram to the right covers the general cap shapes, but there's many, many features present on the cap that are deserving of your scrutiny! Here are several more:

- Color, but this can be variable
- Texture such as scales and warts
- Dryness, or lack thereof
- Zonations of color or light / dark
- Striation (Vertical lines where the gills meet the cap)
- Color changes when bruised

Diagram: David Aurora , Mushrooms Demystified

It is very important to know that many caps will start out concave when young, but then expand like an umbrella as they mature. Just think of the difference between a white button mushroom and a portabello, which are the same species and only different because of age! This is why it's important to see different levels of maturity within a species to understand how they change as they mature.

Scaly caps

There are many different mushrooms that have scaly caps. These scales may also be present on the stems. Sometimes the scales are present even when immature. For others, the scales are the result of cracking as the cap expands during maturation.

Mushrooms that are known for their scaly caps include the Shaggy Mane, the desert shaggy mane, and members of the genus Lepiota and Pholiota.

The photo to the right is a member of Lepiota that I often find in Arizona mixed conifer woods.

Warty caps

Warty caps are almost exclusively a feature belonging to the genus Amanita. But because amanitas are so common and sensational, you can expect to find them often.

The warty appearance comes from a membrane called the universal veil that surrounds the young mushroom in the button stage. As the mushroom matures and expands, the remnants of the veil remain on the cap.

The photo to the right is of Amanita muscaria, the fly agaric.

Striated caps

Striation is the presence of vertical lines on the edge of the cap, which coincide with the attatchment of the gills. This is a common feature on many amanitas, but can be found on plenty of other species as well. Some species will only display striations when their cap is wet / soaked. Their entry in the field guide

I haven't completely identified the mushroom in this photo, but it is definitely an Amanita, and probably a member of the group called "grisettes".

Slimy!

It is fairly uncommon to find mushrooms with the degree of sliminess featured in this photo, but many mushroom caps produce a slippery layer when wet, which helps to shed rain and prevent waterlogging.

It is common to see mushrooms with leaves or needles stuck tightly to their dry caps. This by itself can be a distinguishing feature, especially with the Russulas, which often emerge from the ground fully developed with humus stuck on their caps.

The photo to the right is most likely a member of Gomphodus or Hygrocybe, both of which contain members with notoriously slimy caps.