Complex sentence: The related North American "Paxillus vernalis" has a darker spore print, thicker stipe and is found under aspen, whereas closer relative "P. filamentosus" is more similar in appearance to "P. involutus".
Split into simpler sentences: The related North American species "Paxillus vernalis" has a darker spore print, thicker stipe and is found under aspen. The closely related "P. filamentosus" is similar in appearance to "P. involutus".