Chocolate lowland climate in the narrow band of latitudes where cacao is grown (20 degrees north and south of the equator), the commercial company Mars, Incorporated and the University of California, Berkeley are conducting genomic research in 2017–18 to improve the survivability of cacao plants in hot climates. Chocolate is made from cocoa beans, the dried and fermented seeds of the cacao tree ("Theobroma cacao"), a small, 4–8 m tall (15–26 ft tall) evergreen tree native to the deep tropical region of the Americas. Recent genetic studies suggest the most common genotype of the plant originated in the Amazon basin and
Dresden Botanical Garden unusual "Quercus phellos" as well as "Corydalis nobilis", "Hamamelis", rhododendrons, magnolias, and so forth; a systematic section; an alpine garden collecting a variety of European high mountain plants, including gentian ("Gentiana"), species of saxifrage ("Saxifraga"), "Dianthus caryophyllus", numerous cruciferous plants and primroses; and a garden that contains poisonous, curative, and medicinal plants. The garden also contains five greenhouses of about 1,000 m² total area, containing some 3,000 species, as well as an aquatic greenhouse for "Victoria cruziana" and plants from tropical America including "Ananas comosus", "Tillandsia usneoides", "Theobroma cacao", epiphytic bromeliads, etc. The Great Tropical House (Paläotropis) contains tropical flora