Described by Desjardin (2003) based on two collections,
made nineteen years apart. The type collection came from
Tahoe National Forest, in Sierra County, California, USA.
Lactarius rubriviridis is easily recognized by its hypogeous
growth, irregularly rounded, ovoid to ellipsoid fruitbody
which lacks a peridium; the pitted and ridged, reddish
brown to dark brown gleba is exposed. The gleba has small,
yellowish white to orangish white, irregular to elongate
open locules, and white to yellowish trama which exudes a
deep red latex. It has a rudimentary to well-developed
whitish columella, which slowly stains greenish. More
rarely it has a larger central fleshy area surrounded by
gleba. Currently known from three locations, two in California and one in Oregon. Despite yearly attempts to
relocate it at the type location, it has not been found there
Known from two collections, (from 1350 and 1800m in elevation) in the central and northern Sierra Nevada
mountains in California, and a single location in “central Oregon” (Kuo 2009), presumed to have been made in the eastern
Little is known about the habitat associations of this species. It appears to be quite rare; with only three collections. Despite yearly attempts to relocate Lactarius rubriviridis at the type location, it has not been seen since 2001.
Population Trend: Uncertain
Hypogeous, solitary or scattered, buried under duff. Ectomycorrhizal with Pinaceae; known locations have both pine (Pinus spp.) and fir (Abies spp.). Both California collections have been found in disturbed areas (campgrounds), fruiting in spring. More work is needed to describe the species’ habitat associations and limitations.
This species is likely dependent on mycophagy (primarily eaten by small mammals) for spore dispersal. However, unlike many sequestrate fungi, this species has retained the ability to forcibly discharge spores, and is, at least partially, wind dispersed.
Too little is known about habitat preferences to assess in particular, but in general the changes in forest management and especially fire suppression have changed the composition and structure of Sierra Nevada forests, resulting in fir-dominance, and a higher risk of stand replacing wildfires. Furthermore, an increase in very dry winters has caused bark beetle outbreaks resulting in high mortality of conifers, especially pines.
More work is needed to describe the species’ habitat associations and limitations, and pinpoint potential threats. Targeted surveys for additional populations should be carried out.
Desjardin, D.E. 2003. A unique ballistosporic hypogeous sequestrate Lactarius from California. Mycologia 95: 148–155.
Kuo, M. 2009. Lactarius rubriviridis. Retrieved from the MushroomExpert.Com Web site: