Centroglossa macroceras, the Large-Horned Centroglossa, is an ultra-mini species native to Brazil that is part of the Oncidium alliance. As orchids go, this guy is quite precocious given that it was blooming and in bud right in the flask (i.e., as babies). These are young but blooming-size plants already mounted and ready to bloom for you. Flowers are small and white with green accents–really adorable and quite long lasting. You can see a picture here (many thanks as always to Jay Pfal).
Easy care: moderate to low light, cool to warm temperatures, and keep moist (I water all my mounted stuff daily). Centroglossa macroceras is an excellent choice for terrariums and vivariums, as well.