witch's hat, conical wax cap or conical slimy cap

that's true. and russulas are really annoying to determinate --> especialy on global scale!! therefore it's a good thing, that it will be just a suggestion. no one schould on hand of this suggestion, go out and take the "suggested" agaricus arvensis (maybe xanthoderma). and every spotter schould know that, the decision is by him. if someone really will be sure, he must have a microscope. but this is no mushroom-hunting -gids- determination. i see it as a way to show the beauty of our world --> http://www.youtube.com/watch?v=aWg14IvvMbA&feature=related

when i seen some pictures in my book of both of them i think it could be seperated (nigrescens bigger than conica). but mushroom are very inconstant in form appearance. the psilocybe cubensis as example (i had cultivated myself) depending on how much/or if he stands in sun or shaddow, will be the one time with long stem or short, and the cap also changed. then it is a very big factor - if the substrate is good with the right minerals or if you just take what you can get. therefore the form of some mushrooms isn't as much important as the properties : smell,taste,touch,color or what he does (coprinus comatus - will liquefy / or p.cubensis and some other has discolorations, the H. conica (http://www.google.com/search?q=hygrocybe+conica&rls=com.microsoft:nl&um=1&ie=UTF-8&tbm=isch&source=og&sa=N&hl=en&tab=wi&biw=1108&bih=664) is called in german: SCHWÄRZENDE Saftling (i think it's a better name than wax/slimy cap) it will turn black same as nigrescens (http://www.google.com/search?q=hygrocybe+conica&rls=com.microsoft:nl&um=1&ie=UTF-8&tbm=isch&source=og&sa=N&hl=en&tab=wi&biw=1108&bih=664) --> therefore say some autors its very difficult to seperate those to species.! sadly i did not have an microscope (untill now), with that i could exclude any doubts!!