Frullania is a large and taxonomically complex genus. Historically, Amphijubula, Neohattoria, Schusterella, and Steerea have either been recognized as distinct segregate genera, or, subgenera within Frullania. In contemporary Frullania systematics, Amphijubula has been classified at the subgenus level. Because of its aberrant morphology and nested position within F. subg. Microfrullania based on a prior molecular investigation of the genus, we lower this subgenus to a section as F. subg. Microfrullania sect. Amphijubula. Three taxa, including a new species from New Zealand described here, are currently ascribed to F. sect. Amphijubula. Detailed descriptions and photographs are provided for F. lobulata, F. microcaulis, and F. truncatistyla, as well as a determination key. The distinguishing features of F. sect. Amphijubula include the leaf lobes with acute or acuminate to apiculate apices and the distinctive lobule with a conspicuous projecting, angular cell, inserted directly above the lateral slit. Secondary character-sets that aid as supplementary sources of data for differentiation include the small plant size, and characters associated with the female bract, seta anatomy and elater number.