 The spores are scaphoid (boat-shaped), and have dimensions of 35 – 38 by 12 – 14 µm. They are marked with prominent longitudinal grooves, and when mature, are apiculate (ending abruptly in a short point). The spores typically contain several oil droplets. The paraphyses (sterile cells interspersed among the asci) are 8 – 9 µm long and have internal partitions called septa. The structure of the septa has been investigated using transmission electron microscopy, which has revealed that W. americana has a single pore plugged by a "fan-shaped matrix" — an electron-dense region with a torus-shaped ring of translucent tissue wrapped around it. The pore plug resembles those found in the Sarcoscyphaceae species Sarcoscypha occidentalis and Phillipsia domingensis.
