Erowid Note 2015: The definitions that differentiate between sativa, indica, and ruderalis are considered to be suspect. Although arguments about the terms have persisted in the culture and in print since the mid 20th century, preliminary DNA analysis of named strains do not support simple lay definitions or groupings by obvious external characteristics. The following definitions were considered best-effort in 2000.

• Cannabis sativa, is a tall plant, generally between 8 and 12 feet. The leaves have long thin fingers and are light green. The more equatorial varieties have more yellow pigments to protect the plant from intense light. Sativa buds are long and thin and turn red as they mature in a warm environment. In cooler environments the buds may be slightly purple. Sativa plants smell sweet and fruity and the smoke is generally quite mild. It is a source of fiber for rope and other products and it contains THC which gives smokers the psychic effects they seek. The leaves of this plant are smoked but the most highly prized part of the plant is the top.
  
  
• Cannabis indica, is plentiful in the Mideast, India, and Central Asia especially Afghanistan, Kashmir, and Pakistan. It is a short plant, generally between 3 and 6 feet, and its leaves have short broad fingers. The leaves are generally dark green sometimes tinged with purple. As they near maturity, the leaves may become significantly more purple. It is a strong smelling plant with a "stinky" or "skunky" smell. The smoke of indicas is generally thick and more prone to cause coughing when inhaled. Indicas are the traditional source of hashish.
  
  
• Cannabis ruderalis is a debated third variety of cannabis found in Russia, Poland, and other eastern European countries. Schultes classified cannabis as having three species: sativa, indica, and ruderalis based on the formation of the seed pods. There is some debate as to whether there is justification for this third category. Some features of ruderalis are large seeds, short weedy plants (4-6 feet tall) and a lower level of thc than sativas or indicas.
  
  

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