In this stud -14 specimens belonging to Karaj mycoflora were examined. According to tl results, two form - species; Diplosporonema delastrei, on Silene latifolia subsp. persica and Piggotia ulmi, on Ulmus sp. are reported with new names. For some of the identified fungal specimens, new hosts (matrix nova) are introduced. Moreover, many taxa such as, Marssonina kriegeriana on Salix sp., Septoria polygonorum on Polygonum persicaria, Stagonospora dolIn this studY 14 specimens belonging to Karaj mycoflora were examined. According to tl results, two form - species; Diplosporonema delastrei, on Silene latifolia subsp. persica and Piggotia ulmi, on Ulmus sp. are reported with new names. For some of the identified fungal specimens, new hosts (matrix nova) are introduced. Moreover, many taxa such as, Marssonina kriegeriana on Salix sp., Septoria polygonorum on Polygonum persicaria, Stagonospora dolosa on Phragmites communis, Platychora ulmi on Ulmus sp., Polystigmina sp. on Cerasus sp. and Ramularia decipiens on Rumex sp., are studied and documented as less - known form - species..