Saturday, June 19, 2010

A "stinky" Russula

I have found these Russulas growing on mulch and grass  in my block over the last month. To me, they are not very nice looking mushrooms and, every time I found them, they were braking apart or destroyed by the lawn mowers. Last week I found some clusters that were in good shape and decided to take some home to see if I could determine their identity. On a closer look, the characteristics that stand out on these mushrooms are the strange spermatic smell, the yellow cuticle, and the compressed (shaped like a compressed tube) wide white stipe (stem). Unfortunately, when I collected this mushroom I did not know how difficult it is to identify Russulas and, therefore, did not pay enough attention to some of the important details for this hard task (spore shape and size, cap cuticle separability etc). Indeed, there are many identification keys around the internet, and each one is a little bit more confusing then the other. While searching for information on how to identify my specimens I came across a nice webtool for North American Russulas identification on the Museo Tridentino de Scienze Naturali website, which I highly recommend. Other options are the Pacific Northwest Key Council website (which by the way is a great place for getting identification keys for all North American mushrooms). Last, for specific information on stinky Russulas, there is the key key.

Location: Rockville, MD
Habitat: Gregarious, growing on grass, under conifers

Pileus diameter - 42 x 54 mm | 46 x 48 mm
Pileus height - 22 mm | 15 mm
Stipe length - 40 mm | 43 mm
Stipe diameter at apex - 13 x 15 mm | 13 x 12 mm

Stipe diameter at middle - 13 x 20 mm | 13 x 16 mm
Stipe diameter at base - 13 x 20 mm | 15.5 17.5 mm

Pileus - Yellow/brown, dry, glabrose, cracking, smooth, convex on young specimens and becoming depressed on older ones, round, margin inrolled on young speciments and upturned in older ones, flesh is white, brittle, smell is spermatic
Hymenium - white, gilled, gills are crowded/close, smooth, adnate
Stipe - white, compressed, varying from equal to clavate, hollow with floccose contents, inserted, with brown stain at the base

This looks like a member of the foetid Russula family, possibly R. foetens. Nevertheless, identifying Russulas is not an easy task and, given my naivete when collecting data on this mushroom, I had a hard time identifying it. Some possibilities would be R. amoenolens (a common foetid Russula in North America) which has been described to appear in the region where I live, but the "spermatic" smell seems to be a characteristic of R. foetens (hence the latin name foetens, which means stinky). Many of the characteristics of the mushroom also match R. laurocerasi, R. foentetula, R. and fragrantissima. For now, I'll have to classify it only as Russula sp.

No comments:

Post a Comment