Created: 2007-10-28 20:27:39
By: Administrator (admin)
Summary: Copied comment to the Names

I put a copy of your comment about distinguishing between A. mellea and A. ostoyae on the name pages for each species along with some of the bits of my comment.

Created: 2007-10-27 22:44:13
By: Darvin DeShazer (darv)
Summary: Deciding between A. ostoyae and A. mellea

In California, both Armillaria mellea and A. ostoyae have a thick, felty annulus and they are the only Armillaria species here to have that character. They differ by the color of both the cap and the annulus.

A. mellea has a white to yellow edge on the annulus, the cap is honey yellow and the disc is darker than the margin giving it a two-tone appearance. The cap is smooth and the hairs are indistinct.

A. ostoyae has a brown edge on the annulus, the cap is brown with dark hairs.

Created: 2007-10-27 06:07:51
By: Nathan Wilson (nathan)
Summary: Deciding between A. ostoyae and A. mellea

What rule do you use? I generally use A. mellea for the ones that grow on hardwoods and A. ostoyae for the ones on conifers. I do know that Tom Volk id’ed a collection from southern California growing on hardwood as a slightly unusual form of A. mellea. I also sent him a sample from Santa Cruz that came out as A. mellea. Apparently the California material mated with the true A. mellea, but it was not a typical mating. Macroscopically I remember Tom noting that the California material has a scalier cap than classic A. mellea. Based on his key it looks like we should be doing more microscopy and looking for clamps at the base of the basidia. Personally I have a hard enough time find a good basidia, much less figuring out whether there’s a clamp at the base. Have you had much success with that? Any recommendations?