Family: Cannabaceae (Hemp)
Other names: marijuana: pot, weed, grass, herb, bud, reefer, mary jane, ganja, dope, chronic, etc.; hemp: industrial hemp, Indian hemp
Name meaning: Marijuana is Spanish for mary jane, the Spanish common name for the plant. (Before it was made illegal, both varieties were commonly known as hemp, but opponents of the drug began calling the plant by the Spanish name to associate it with Mexican immigrants, using racism to denigrate the plant.) Hemp comes from the Old English word for the plant, hænep, which incidently comes from the same ancient root as cannabis. Cannabis is the Latin word for hemp, and is also the origin of the word "canvas". Sativa means "cultivated".
Origin: Cannabis is native to South Asia, where it was first cultivated and developed into the two varieties. It is now a cultivated crop and an invasive in many parts of the world.
Range: Marijuana is grown illegally worldwide, though variations in climate and law enforcement tend to concentrate it in certain areas, such as Canada and Latin America. Hemp is grown legally in many countries worldwide, most often in temperate climates. Cannabis has spread into the wild in many parts of the world, though eradication efforts have been somewhat successful in places like the US.
Habitat: Both hemp and marijuana are most often found in well-tended cultivated plots. In the wild, cannabis is usually found in sunny waste areas.
Life cycle: Annual
Description: Cannabis is probably the most well-known plant in the world due its widespread use and its controversy. Cannabis can grow up to 10 feet tall, though it is usually shorter, and has alternate leaves which are palmately lobed with 5-9 sharply toothed lobes. At the top of the plant is a spike or spikes of green-brown flowers. The plants are dioecious, meaning that male and female flowers grow on separate plants. Cannabis has been bred over thousands of years into two distinct varieties, marijuana and hemp. Marijuana is bred for its Tetrahydrocannabinol (THC) content, found only in the female plants, which causes a euphoric effect and has many medicinal properties. Hemp, which has effectively zero THC, is bred for its stem fiber, which makes very strong rope and cloth, and its seed oil. The uses listed below are divided into marijuana uses and hemp uses, although there is some crossover. Unfortunately, it is very difficult to distinguish marijuana and hemp on sight, which is one of the reasons hemp is illegal to grow in the US and many other countries.
Notes: Some botanists consider hemp to be a separate species, known as C. indica, while others consider it only a variety of C. sativa. The rules for taxonomic classification of plants are murky and there is a lot of gray area, leading to arguments between "lumpers" and "splitters". Adding to the confusion, many specialized strains of marijuana have been bred with hemp. Since I'm not an expert on plant taxonomy, I usually just go with what the USDA says, which in this case is that both hemp and marijuana are subspecies of C. sativa, that is, C. sativa indica and C. sativa sativa, respectively.

Uses

Edible: Hemp seeds can be eaten raw, roasted, or ground into nut butter, or the seeds can be pressed into a vegetable oil. The seed oil is very high in omega fatty acids, and it is one of the best vegetarian sources of this essential nutrient. Due to the high amount of unsaturated fat in the oil, it can't be used for frying, but it can be used in foods such as salad dressings. The leaves can be eaten raw and are also used for flavoring in foods such as soup. Hemp foods are perfectly legal in most places, including the US, because they can't get you high. Marijuana can be eaten in the same ways, but marijuana foods can get you high, depending on the potency and the recipe. Pot brownies are a favorite among marijuana users.

Medicinal: Marijuana has been an important medicine for thousands of years, thanks to the chemical THC, which contains many medicinal properties. The buds of female plants contain the most THC, though the leaves are also used, and some use the THC-rich resin, known as hash. In the ancient world, marijuana was used for a variety of disorders, such as malaria, dysentary, fever, cancer, worms, jaundice, leprosy, nervous disorders, and whooping cough, and as a pain reliever, especially during childbirth, as a sedative, a demulcent, an emmenagogue, and as an appetite stimulant. It has also been used to assist in withdrawal from alcohol and drugs. Marijuana is being increasingly used in modern medicine due to its effectiveness and safety. Of primary importance is its use as an analgesic (pain-relieving) drug for those suffering from chronic pain. Because it is supremely effective for pain and has very few side effects, it is increasingly popular among doctors and patients for chronic pain. Another important use is as an antiemetic (preventing and relieving vomiting). Studies show that marijuana is more effective than more-commonly prescribed antiemetics, is easier to control in terms of dosage, and has virtually no side effects. Because of these properties, it is used for cancer patients who are undergoing chemotherapy and for AIDS patients for relief from nausea and vomiting due to the disease itself and the AZT drug treatment. Other common uses in modern medicine include its use as a muscle relaxant for muscular disorders such as Multiple Sclerosis; to relieve intraocular pressure for glaucoma; and as an appetite stimulant for AIDS wasting syndrome, chemotherapy-related loss of appetite, and anorexia nervosa. Of particular interest to me is the theory that marijuana can be used to prevent migraine headaches. Based on personal experience and anecdotal evidence from others, I believe this rumor may be true; unfortunately the DEA is very strict on using cannabis in medical trials, and there simply hasn't been enough research done on this. Migraine sufferers have also used marijuana during migraines for its pain relieving, anti-nausea, and sedative properties, which are exactly what one needs during a migraine. Studies suggest that THC may have anti-tumor properties, which could potentially be useful in cancer treatment in the future. In the US, medical marijuana is illegal federally, but currently eleven states have passed provisions that allow the use of medical marijuana for those with a prescription. In California, for instance, medical marijuana patients must have a medical card from a doctor, and may grow their own cannabis or purchase it at a licensed dispensary. Unfortunately, the federal government continues to prosecute marijuana patients and distributors under the Controlled Substances Act, the use of which has been called unconstitutional by those advocating states' rights in regards to medical marijuana issues. The use of the act for this purpose was upheld by the Supreme Court in 2005.

The primary method of using marijuana is smoking, and there are myriad ways to do this. The familiar marijuana cigarette ("joint") is popular, though most serious smokers use a pipe or a bong, which is a water pipe. A promising method that is growing in popularity is the vaporizer, which is designed to burn marijuana at the exact temperature to release only the THC and none of the harmful tars that usually come along with it. Unfortunately, the vaporizer is hard to obtain in most places because of laws against paraphernalia, though it can be found in places like Amsterdam and Vancouver, and some (highly skilled) users are able to build their own. Other ways of using marijuana include using it in cooking and baking (e.g., pot brownies) and brewing it into tea. To be effective when eaten, the marijuana must be heated to around 375 ° F. In addition to the use of straight cannabis, there are several pharmacutical drugs that have been based on or derived from cannabis, including Marinol, which is synthetic THC, and Sativex, which is derived from a carefully-bred strain of cannabis.

Utilitarian: Hemp is one of the most important sources of fiber in the world. It makes excellent cordage, cloth, and paper. Before marijuana became such a huge issue, hemp was an important crop in the United States, and before we started making paper from tree pulp, hemp was one of the most common types of paper. In fact, the Declaration of Independence was written on hemp paper. The only reason that hemp is illegal in many places is that it's difficult to tell it apart from marijuana on sight (though of course prejudice against the plant doesn't help). Hemp is still an important fiber crop in parts of the world, such as Canada, Britain, and Germany. Hemp is considered to be an environmentally-friendly alternative to cotton, which requires more land and the use of harmful pesticides, and to harvesting trees for paper. In addition to the fiber uses, the oil from the seeds is used as a fuel. Hemp can be used as a biofuel, and hemp-based plastic is a newly developed alternative to oil-based plastics. Interestingly, hemp's utilitarian uses are at least partially at fault for the current illegality of cannabis — in the early 20th century William Randolph Hearst, the newspaper tycoon, used his newspapers to wage a propaganda campaign against marijuana in order to help his tree paper business. Unfortunately, it worked, and both plants became illegal in the US with the Marihuana Tax Act of 1937.

Magical: Marijuana has long been smoked ritually by many people. Probably the oldest existing tradition is among Hindu ascetics known as sadhus, who use it in their quest for moksha (release from the cycle of reincarnation). Some biblical scholars believe that cannabis was used by ancient Hebrews and early Christians. In addition to regular religious use in many faiths, there have been marijuana-centered cults where the plant was worshipped. Though most marijuana use today is recreational rather than religious, some groups, such as Rastafari, continue to imbue the activity of smoking with religious reverence. Rastafari regard cannabis as highly sacred and consider it to be the Tree of Life mentioned in Genesis. Many users have remarked that marijuana opens up the mind to wider perception and higher levels of conciousness, and many groups have used it in mysticism to achieve union with God or the universe, including Sufis, Rastafari, Gnostic Christians, and Hindus. In addition, many individuals not connected to specific religions use it spiritually. Aside from these spiritual uses, marijuana is also used for necromancy (communication with spirits or departed souls to divine the future), divination, protection from evil, luck, and as incense. Hemp fiber and oil have also had religious significance, such as in Shintoism, where ceremonial robes and other religious items are made of hemp.

Warning: Marijuana is illegal in most places, so be aware of your local laws. Marijuana is, in general, much less dangerous than it is made out to be, and certainly less harmful than legal drugs like tobacco and alcohol. It is impossible die from marijuana, unlike most other illegal drugs and many legal ones. Most of the supposed scientific evidence for brain damage, infertility, etc. have been disproven. In addition, studies suggest that THC has anti-tumor properties, which may account for its apparent inability to cause cancer. (See the book Marijuana Myths, Marijuana Facts for more information on the health effects of marijuana.) However, smoking any substance is not good for your lungs, so you might consider using a safer method such as ingestion, or smoking with a vaporizer, especially if you have sensitive lungs. While there is no evidence that driving under the influence of marijuana impairs ability to drive (even after numerous studies trying to prove otherwise), as it is a mind-altering substance, driving and operating machinery under its influence is probably not advisable.

Where to find cannabis

First of all, growing, selling, possessing, and using marijuana is illegal in most places. There are some exceptions, places where small amounts have been decriminalized (such as Canada and a few US states), and medical marijuana is legal (with a prescription) in some states. Hemp is also illegal to grow in many places, including the US, although it is legal in other countries, such as Canada, and importing and buying hemp products is legal in the US. Be aware of your local laws before you consider using cannabis for any purpose.