Collection location: Clarion, Pennsylvania, USA [Click for map]
Voucher Number: NAMA 2011-247
Russula michiganensis Shaffer
Identified by: Donna Mitchell
Collected by: Claude Martz
Voucher Specimens are located at the Botany Herbarium,
Field Museum of Natural History, Chicago.
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Thank you for the information. I’ll have to wait to study R. albonigra to make me a better idea, and a comparison between albonigra and michiganensis. However, making the separation of two species only about one micron spores ornaments seems to me rather risky, even impossible ..
According to Shaffer’s 1962 key R. albonigra is separated from R. michiganensis by having spore ornamentation less than 0.2 um tall, though R. michiganensis does not have ornamentation much over 0.3 um. He also uses spore size, distance between gills, and a differentiated cuticle to separate the two. Modern interpretations have R. albonigra with a white cap and quickly turning black by touch, whereas R. michiganensis is described as starting either white or light-yellow when young and may stain slower to brown/black.
I haven’t looked at sequences of this group in any great detail, so I’m not sure how much genetic/geographic variation there may be in this group. I have found that Russula dissimulans seems to be a good name for the eastern Russula nigricans, however, the western Russula nigricans is indeed identical to the European species.
At the moment, I study a russule much like R. michiganensis.
Could you tell me, please, the characteristics that have decided you identify as R. michiganensis? What could be the differences with R. albonigra?
Created: 2011-11-11 22:52:39 EET (+0200)
Last modified: 2015-08-08 03:48:34 EEST (+0300)
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