All tea leaves come from the same plant, Camellia sinensis. Each tea type (black, green, oolong, white, pu-erh) is determined by how the tea leaf itself is picked and processed. For example, black tea is oxidized (fermented) but oolong tea is only semi oxidized.
Herbal and fruit tisanes are often mistakenly referred to as "tea" but this is not the case, as they have not come from the Camellia sinensis plant. However, they can still be brewed and enjoyed in the same manner.
"A cup of tea makes everything better" - Anon