Perfect Seed Fern Fructification from Saint Clair Pennsylvania

Description: This phenomenal specimen was self-collected from an abandoned coal pit by St Clair, Pennsylvania. From my research the seed appears to fit the classification Holcospermum. A large seed with strong ribbing, often numbering eight to ten. The seeds are rarely found and generally detached from the fern fronds, making identification difficult. The ferns most commonly found in the St Clair area are Alethopteris, Neuropteris, Pecopteris, and Sphenophyllum.