Phyllactinia guttata Cleisthecium
The cleistothecia of fungi in the genus Phyllactinia have two types of appendages: an equatorial group of radiating appendages that are unbranched and have bulbous bases and a crown of repeatedly branched shorter appendages that secrete mucilage. The bases of the bulbous appendages is thick-walled above and thin-walled below. As the cleistothecia dry, the appendages will bend downward. This downward movement occurs as the thin-walled area buckles inward. This downward pressure of the appendage tips will lever the cleistothecia free from the mycelium. The mucilage that has been secreted between the apical crown of branched appendages serves to adhere the cleistothecia onto leaves and twigs. Cleistothecia contain multiple asci that each usually contain only two ascospores.

Phyllactinia sp. CleistotheciumPhyllactinia guttata Cleistothecia 25xPhyllactinia sp. Appendage
Representative Species

Phyllactinia corylea

causes powdery mildew disease of oak, elm, tulip poplar, crepe myrtle, ash, birch, and dogwood

Phyllactinia guttata

causes powdery mildew disease on oak, pecan, honey locust, elm, dogwood, beech, magnolia, and birch

Return to Powdery Mildew Genera Key