North American species of Lactarius / L. R. Hesler, Alexander H. Smith.

Subgenus Tristes

353

150 ui) of the hyphae. The ixotrichoderm simply collapses as moisture
escapes from the layer and the hyphae become more or less cemented
together and matted down. If sections are not properly revived, the
hyphae never reassume their original arrangement. The slime on the
pileus may be 2 mm deep in wet weather. The pleurocystidia (as
macrocystidia) are much like those of L. vinaceorufescens-they tend to
collapse in age in many collections. Section immature basidiocarps to
gauge their frequency accurately.
The color of the pileus is blackish when fresh, but, on standing in
the herbarium (in contact with naphthalene) for a few years, fades to
drab or gray and often an ochraceous tone develops. Smith 79247 from
Oregon had a strong and acrid taste followed by a bitter taste, and the
latex in about 2 hours dried greenish. In Smith 56532 from California
the latex was unchanging and the lamellae stained ochraceous along
the edges. The lamellae were whitish becoming yellowish (lacking a
pinkish gray flush). In Smith 56278, collected 5 days earlier at Trinidad, the gills stained brown where injured.
Because the color of the spore deposit, color changes of the latex, and the staining of injured tissues have been standard characters
in the taxonomy of Lactarius, their variation in this species is of more
than passing interest. As an aid to further study of this problem we
have here grouped those of our collections upon which we have recorded the data, into groups as follows:
Group 1. Spores white to off-white; latex changing to olive or staining
tissues olive to olive-brown: Smith 40910, 54534 (type),
82337, 82342, 82382, 82413, 82416, 82420, 82448, 82579,
82831, 82833, 83015, 83017, 83063, 83064, 83066, 83729.
Total 18 collections.
Group 2. Spores white to pale cream; lamellae staining brown (no
olive present). Smith 16897, 56278, 79247, 82624, 82752,
83016, 83065, 83769. 8 collections.
Group 3. White spored; no stains. Smith 56532, 82082, 82627, 83062.
4 collections.
Group 4. Spore deposit yellow (after air-drying); green stains (or
olive) present. Smith 82414, 82447, 82451, 82745, 83728.
5 collections.
We recognize Group 1 as the type of L. kauffmanii. It is more
common than the records indicate, and is unquestionably a widely
distributed taxon in the Northwest. The remainder of the groups are
not recognized as individual taxa at any level as we feel there are several possible discrepancies which may be involved in the groupings.
Our data were accumulated over a 25-year period, but only recently
have we taken care to check for long-delayed staining-and when this