section_path: Cultivation and production/Species variations
section_name: Species variations
paragraph_text: Species variations
  
  Of the two main species grown, arabica coffee (from C. arabica) is generally more highly regarded than robusta coffee (from C. canephora). Robusta coffee tends to be bitter and has less flavor but a better body than arabica. For these reasons, about three-quarters of coffee cultivated worldwide is C. arabica. Robusta strains also contain about 40–50% more caffeine than arabica. Consequently, this species is used as an inexpensive substitute for arabica in many commercial coffee blends. Good quality robusta beans are used in traditional Italian espresso blends to provide a full-bodied taste and a better foam head (known as crema).
  
  Additionally, robusta is less susceptible to disease than arabica and can be cultivated in lower altitudes and warmer climates where arabica does not thrive. The robusta strain was first collected in 1890 from the Lomani River, a tributary of the Congo River, and was conveyed from the Congo Free State (now the Democratic Republic of the Congo) to Brussels to Java around 1900. From Java, further breeding resulted in the establishment of robusta plantations in many countries. In particular, the spread of the devastating coffee leaf rust (caused by the fungal pathogen Hemileia vastatrix), to which arabica is vulnerable, hastened the uptake of the resistant robusta. The pathogen and results in light, rust-colored spots on the undersides of coffee plant leaves. It grows exclusively on the leaves of coffee plants. Coffee leaf rust is found in virtually all countries that produce coffee.
  
  Beans from different countries or regions can usually be distinguished by differences in flavor, aroma, body, and acidity. These taste characteristics are dependent not only on the coffee's growing region but also on genetic subspecies (varietals) and processing. Varietals are generally known by the region in which they are grown, such as Colombian, Java, and Kona. Arabica coffee beans are cultivated mainly in Latin America, eastern Africa or Asia, while robusta beans are grown in central Africa, southeast Asia, and Brazil.
  
  Coffee can also be blended with medicinal or functional mushrooms, of which some of the most frequently used include: lion's mane, chaga, cordyceps and reishi. Mushroom coffee has about half the caffeine of standard coffee. However, drinking mushroom coffee can result in digestive issues and high amounts can result in liver toxicity. There is little clinical evidence for the benefits of mushroom coffee.