The filaments can gelatinize by absorbing water and are thought to function in helping the ascomata adhere to the surface on which they grow, like the underside of leaves.

[9] In P. guttata, the foots are cylindrical, irregular in width, 32–72 by 7.5–25 μm, and divided into 2–10 branchlets in the upper part.

The short, bulbous branchlets on the multi-branched upper part of the foots are unique among the Phyllactinia and are a distinguishing taxonomic characteristic of this species.

[10] Examples include species from the Betulaceae family (Betula, Carpinus, Corylus, Ostrya), the Fagaceae (Castanea, Fagus, Quercus) and the Juglandaceae (Juglans, Platycarya, Pterocarya).

It is also found on the genera Acer, Aesculus, Aralia, Asclepias, Azalea, Buxus, Catalpa, Chionanthus, Cornus, Frangula, Hedera, Humulus, Morus, Paliurus, Populus, Prunus (including almonds, Prunus amygdalus,[11]), Rhamnus, Ribes, Salix, Sorbus, Syringa, and Ulmus.