frondosa is widely variable in color. The top right photo shows
a mushroom with dark brown caps. The photo below that illustrates a mushroom in the shade,
under a large branch, which is very light on the top and gray to tan around the margins of
the lowest caps. The lower caps received more sunlight.
From my experiences, direct sunlight darkens the mushroom. I have seen
clusters of pure white fronds growing where no sun gets to the mushroom at all. I have
some old slides of pure white mushrooms. If I can find them I'll post them when I get a
The third and forth pictures below right show new budding mushrooms,
where future caps begin as tiny brown bumps on a lighter colored surface.
Given the right conditions, bushy clusters will grow for more than a
week with the underside pore surface getting thicker with pores enlarging over time.
Each frond or cap can grow from a half to five inches across and is
usually darker to the outward edges of the "caps." The entire fruiting body can
be as big as several feet across and weigh 20 to 30 pounds.
Grifola frondosa is a polypore, a mushroom which disperses its
spores from pores as opposed to gills.
The caps are firm and juicy. The stem is thick, white, firm and branched
The spore print is white.
- Roy Reehil