Any similarities between Phylloglossum and specific subgenera of Lycopodium sens. lat. have been difficult to determine, because the reduced sporophyte of Phylloglossum has few characters for comparison. Gametophytes can provide useful characters, but it is difficult to find Phylloglossum gametophytes in nature. These gametophytes have been grown in axenic culture for study. Spores of Phylloglossum germinate in the dark on a nutrient medium containing minerals and glucose. No germination occurs in the light. In early development, a globular gametophyte forms that later becomes cylindrical (...)