The sexual, thick walled and resting spores of the rust fungi is known as

The sexual, thick-walled, and resting spores of the rust fungi are known as Teliospores.
Teliospore cells are both thick-walled and pigmented allowing them to remain dormant throughout winter before germinating the following spring to produce short-lived, thin-walled basidiospores.
Teliospores function to shield genetic material during the stresses of dispersal between host plants.