What does LEAU stand for?

Least Auklet - Common English name - Scientific name: Aethia Pusilla - American Ornithologists Union four-character bird identification (IBP)

Leavenworthia aurea Torr. - Scientific name - Common name: golden gladecress - Family: Brassicaceae - USDA National Plant Data Center symbol - Botany - Taxonomy (USDA)