SORUS

[so.rus] n, pl so.ri [NL, fr. Gk soros heap] (1832): a cluster of plant reproductive bodies: as a: one of the dots on the underside of a fertile fern frond consisting of a cluster of sporangia b: a mass of spores bursting through the epidermis of the host plant of a parasitic fungus c: a cluster of gemmae on the thallus of a lichen