 Of the species of Marginatae associated with willow , five ( I. salicis @-@ herbaceae , I. substellata , I. praetervisa , I. salicis and I. mixtilis ) can be readily distinguished from I. saliceticola as their spores feature distinct , strongly protruding excrescences . In addition , they are found in vastly different habitats : I. mixtilis and I. praetervisa favour willow only in montane habitats , while I. salicis @-@ herbaceae and I. substellata grow exclusively in montane habitats . I. salicis is rare in Nordic countries , and is typically collected from dunes . Of the other two listed by Vauras and Kokkonen , the spores of I. dunensis are distinctly larger and of a different shape to those of I. saliceticola , and the cystidia are shorter . While the species is typically found on the beach , it grows on fine sand , and has not been recorded in Finland . I. obtusiuscula also has larger spores of a different shape , and they are a darker colour , owing to their thick cell walls . Phylogenetic analysis of the respective internal transcribed spacer sequences has confirmed that I. obtusiuscula and I. saliceticola are separate species . 
