There are 1,500 different species of begonias and eight types based on horticultural classifications, according to the American Begonia Society. The eight horticultural types include cane-like, shrub, rhizomatous, semperflorens, tuberous, rex, trailing-scandent and thick-stemmed begonias. The tropical flowers are annuals, or herbaceous perennials, that prefer bright light without direct sunlight.
Cane-like begonias have tough stems similar to bamboo that can grow up to 12 feet tall. Leaves of superba canes grow to 14 inches long. Begonia shrubs also reach 12 feet high with leaves up to 24 inches long. Begonia shrubs get their name from multiple stems that come up from the ground to appear like a full shrub.
Rhizomatous begonias are known for huge displays of flowers that cover the entire plant. The largest of rhizomatous types have leaves that get as big as 3 feet long. Semperflorens have rounded, waxy leaves that are green or bronze. Semperflorens flowers are generally single and double types.
Tuberous begonias are bedding plants used in greenhouses with flowers that grow to the size of dinner plates. Some tuberous types form a bonzai-like structure close to the ground. Trailing-scandent are typified by glossy flowers.
Rex begonias have showy, multicolored leaves that are more prominent than their flowers. Thick-stemmed varieties send stems from the base of the plant rather than farther up the stem. These larger stems show when lower leaves drop and leaves are only on the tips of plants.