The two subspecies of cannabis are known as Cannabis indica (hemp) and Cannabis sativa (hemp and marijuana). A third type found mainly in Russia, Cannabis ruderalis has a lower THC content than either C. sativa or C. indica, so it is rarely grown for recreational use and the shorter stature of C. ruderalis limits its application for hemp production. Cannabis ruderalis strains are high in the cannabÑ–noid cannabidiol, so they are grown by some medical marijuana users. (The term, marijuana originally spelled as "marihuana", "mariguana", etc., originated in Mexican Spanish.) Marijuana is now mostly an American term.
Tall, sturdy cannabis plants were grown by early civilizations to make a variety of foods, oils, and textiles. These plants were bred with other plants with the same characteristics, leading to the type of cannabis known as hemp. It is virtually impossible to get high on hemp, although it does have some medicinal benefits.
Other plants were recognized for being psychoactive and were bred selectively for medical and religious purposes. This led to unique varieties of cannabis known as marijuana.
The core agricultural differences between medical cannabis and hemp are largely in their genetic parentage and cultivation environment. Marijuana growers usually try to maintain stable light, temperature, humidity, CO2 and oxygen levels, among other things. Hemp is usually grown outdoors to maximize its size and yield, and less attention is paid to individual plants.
Cannabis plants contain unique compounds called cannabinoids. Current research has revealed over 60 different cannabinoids so far, but THC is the most well known. THC is credited with causing the marijuana high. While marijuana plants contain high levels of THC, hemp contains very little.
Countries like Canada have set the maximum THC content of hemp at 0.3%. Any cannabis with higher THC levels is considered marijuana. Medical marijuana produces anywhere between 5-20% THC on average, with some strains up to 25-30% THC.
Before 1910 Bristol-Meyer’s Squib and Eli Lilly included cannabis and cannabis extracts in their medicines to cure common household ailments. The US Bureau of Narcotics, during the 1930s, used the name “marijuana” when campaigning against the plant, and showing its new “foreign” identity. The Marihuana Tax Act of 1937 federally criminalized the cannabis plant in every US state.
All cannabis is federally illegal to produce in the United States. Both hemp and marijuana are classified as Schedule I drugs under the Controlled Substances Act (non-psychoactive hemp is not included in Schedule I). It is legal to import hemp products into the United States. The US Drug Enforcement Administration is preparing to decide whether cannabis should be reclassified under federal law during The first half of 2016.
In the US, eight states allow people with certain medical conditions to use marijuana. Seventeen states have passed laws opening the door to marijuana use as long as the drug is extremely low in THC, the intoxicating ingredient. Five states have removed the potential for jail time for those caught with small amounts of the drug. Some states both have approved marijuana use by sick people and removed jail sentences for recreational users, including California, Connecticut, Delaware, Maine, Maryland, Massachusetts, Minnesota, Nevada and Rhode Island. Four states and Washington, D.C., allow marijuana possession in small amounts by adults over 21 for any reason, including Alaska, Colorado, Oregon, Washington.
Outside the US, hemp is grown in more than 30 countries. In 2011, the top hemp-producing country was China, followed by Chile and the European Union. Hemp production is also expanding in Canada.
Marijuana remains illegal in most countries, but a few, such as Israel and Canada, have recently started to regulate marijuana as a medicine. Legalization supporters consider possession either legal or tolerated in Argentina, Bangladesh, Cambodia, Canada, Chile, Colombia, the Czech Republic, India, Jamaica, Jordan, Mexico, Portugal, Spain, Uruguay, Germany, and the Netherlands.
Hemp can be made into wax, plastic, resin, rope, cloth paper, fuel, detergent, paint, snacks, flour, beer, insulation, carpeting, paneling, auto parts, and an estimated 25,000 products. Thomas Jefferson drafted both the Declaration of Independence and the U.S. Constitution on hemp paper.