Abundant specimens of a new type of microscopic reproductive structures are present in a lateral branching system of the Early Devonian euphyllophyte Kenrickia bivena. The fossils are preserved by calcium carbonate permineralization in fluvial deposits of the Emsian (c. 400-395 Ma) Battery Point Formation, exposed along Gaspé Bay (Quebec, Canada). The reproductive structures, termed sporocarps hereafter (pending elucidation of their taxonomic affinities) are roughly isodiametric and up to 200 µm in size. They appear spheroidal but may exhibit flat sides and small papillate protrusions in some planes of section; some are compressed or distorted taphonomically into less regular shapes. The sporocarp wall consists of two layers: a dark, dense inner layer of relatively even thickness (5 µm), and a lighter colored outer layer with agglutinated structure that can look at times granular or vermicular. The outer layer, up to 25 µm thick, is denser toward the contact with the inner layer and grades into looser packing toward the sporocarp surface, which has an irregular relief and where cells (4-9 µm) are sometimes visible. The sporocarps are filled with c. 300-400 tightly packed thin-walled spherical bodies 17-25 µm in diameter, most of which preserve inside one spheroidal inclusion c. 6 µm in diameter. The sporocarps are distributed throughout the spaces formerly occupied by parenchymatous tissues of the K. bivena axis; here, they are associated with coprolites 62-100 µm in size. Given the state of preservation of the host plant, it is impossible to know whether the sporocarps developed during the plant’s life or after its death. Some of the sporocarps are immediately adjacent to cells of the sclerenchymatous plant tissues (xylem and outer cortex) and seem to affect their walls, which are conspicuously thinner at the contact with the sporocarps. At least one sporocarp is attached to a coprolite. The taxonomic affinities of the sporocarps are unclear. They are morphologically comparable to reproductive structures produced by some fungi (Ascomycota, Mucoromycota), or could alternatively represent animal (arthropod, nematode) egg masses. Both fungi and animals can produce reproductive structures inside plant tissues. Such foreign bodies are often isolated by the plant host, which produces barriers (consisting of secondary metabolites or remains of necrotized cells); the structure of the sporocarp walls, with their consistent well-differentiated layering, precludes interpretation as a host response product. If the spheroidal inclusions inside the thin-walled bodies are nuclei rather than conglobated cell content, as suggested by their consistent shape and size, a fungal interpretation is less likely because fungal nuclei are typically smaller. Additionally, the coprolites indicate that animals were present in the host plant. However, the cellular structure of the outer sporocarp walls is inconsistent with animal origin. A thinning of the plant cell walls at the contact with the sporocarps suggests enzymatic activity of the latter, which would be expected from fungal structures but cannot exclude animal egg sacs.