Celebrated in the fall for their vibrant foliage, red maple trees (Acer rubrum) produce equally vibrant reds and yellows in early spring when they are flowering. Most red maples have dense clusters of either male or female flowers. Under certain conditions, a red maple tree can switch from male to female, from male to both male and female (hermaphroditic), or from hermaphroditic to female. The showier male, or staminate, flowers contain between 4 and 12 stamens, with long, slender filaments and red (young) or yellow (mature) anthers at their tips. Both red sepals and petals can be seen at the base of the stamens.