B. australis

B. australis may refer to:
 * Baptisia australis, the blue wild indigo or blue false indigo, a herbaceous perennial plant species native to North America
 * Barbosella australis, an orchid species
 * Brunonia australis, the blue pincushion or cornflower, a perennial herbaceous plant species found in Australia
 * Botryosphaeria australis, a synonym for Neofusicoccum australe, a fungus species