Flora, Roman Goddess of flowers, begins her appearance in the spring soon after the first frosts melt, with the appearance of the crocus. The festival of Floralia is still celebrated from April 28th through May 1st, and has a correlation with the May Day festivals of pagans everywhere. It is a fertility rite associated with both sisters, Flora for the birth of the flowers and Fauna for the birth of the spring lambs and other animals.
In Roman mythology, Tellus, Goddess of the Earth had the two daughters, and they had small temples for bringing flowers and small animals for honoring their contribution to the plants and animals that made up the food stores for the people of Rome. (Tellus is closely associated with the Greek Goddess Ceres and has her own festival held from January 24-26 to set out offerings that the frozen ground would once again yield food for the coming year.) Flora is also identified with the Greek Goddess Chloris (See where we get the name "Chlorophyll"? The naturally occurring chemical that causes plants to grow green.)
Fauna is associated with the Greek mother earth Gaia Goddess and had temples built in her honor as early as 268 BCE, or Before Common Era, which is a term largely used by pagans and neopagans everywhere who choose to use it rather than B.C., or "Before Christ". The Goddess Fauna has her own festival which is called Fordicidia and is traditionally held on April 15th, when cows are just getting ready to bear their calves.
A very simple way for today's practitioners of the mother earth faith is to celebrate Imbolc on February 2nd (The Roman Catholic Church changed it to "Groundhog Day" when they were trying to convert pagans to Christianity. It was thought that if they were allowed to keep some of their holidays and simply twist them slightly it would make the conversion easier) to observe that the winter was ending, and to celebrate both Flora and Fauna along with other fertility Goddesses on May Day, May 1st every year as a symbol and hope that the coming months would bring fertility and prosperity. Flora, Roman Goddess of flowers, is honored during these celebrations with the wearing of a crown of flowers in the hair; while Fauna is honored with the letting loose of rabbits (Hmmm Easter bunnies?)