One of the most curious uses of hemp is as a fence to prevent pollen transfer in commercial production of seeds. Isolation distances for ensuring that seeds produced are pure are considerable for many plants, and often impractical. At one point in the 1980s, the only permitted use of hemp in Germany was as a fence or hedge to prevent plots of beets being used for seed production from being contaminated by pollen from ruderal beets. The high and rather inpenetrable hedge that hemp can produce was considered unsurpassed by any other species for the purpose. As well, the sticky leaves of hemp were thought to trap pollen. However, Saeglitz et al. (2000) demonstrated that the spread of beet pollen is not effectively prevented by hemp hedges. Fiber (i.e. tall) cultivars of hemp were also once used in Europe as wind-breaks, protecting vulnerable crops against wind damage. Although hemp plants can lodge, on the whole very tall hemp is remarkably resistant against wind.
THC and its major (inactive) metabolite, THC-COOH, can be measured in blood, urine, hair, oral fluid or sweat using chromatographic techniques as part of a drug use testing program or a forensic investigation of a traffic or other criminal offense.[52] The concentrations obtained from such analyses can often be helpful in distinguishing active use from passive exposure, elapsed time since use, and extent or duration of use. These tests cannot, however, distinguish authorized cannabis smoking for medical purposes from unauthorized recreational smoking.[141] Commercial cannabinoid immunoassays, often employed as the initial screening method when testing physiological specimens for marijuana presence, have different degrees of cross-reactivity with THC and its metabolites.[142] Urine contains predominantly THC-COOH, while hair, oral fluid and sweat contain primarily THC.[52] Blood may contain both substances, with the relative amounts dependent on the recency and extent of usage.[52]

Only a handful of countries have legalized recreational marijuana. Uruguay was one of the first, in 2013. The Netherlands is perhaps the country most known for legal marijuana, yet the drug is illegal there. Spain has given its citizens the rights to grow and consume cannabis privately. Peru also allows citizens to possess marijuana as long as it is for personal, private use. As in Costa Rica, where people can have a “small amount,” without legal trouble.
Medical marijuana in the U.S. is controlled at the state level. Per federal law, cannabis is illegal as noted in the Controlled Substances Act, but the federal government has stated they will not actively prosecute patients and caregivers complying with state medical marijuana laws. However, use of medical marijuana outside of the state laws for illegal use or trafficking will not be tolerated by state or federal government.
Marijuana regulators in Washington State will entertain sweeping changes to how marijuana is tested, processed, packaged and sold in one of the U.S.’s oldest recreational marijuana markets, officials announced late Wednesday. Recreational cannabis has been sold in regulated retail outlets in Washington since 2014. Consumers there pay one of the country’s highest tax burdens, generating … Continue reading Washington State Prepares To Rewrite Marijuana Testing And Packaging Rules
The use of Cannabis for seed oil (Fig. 36) began at least 3 millennia ago. Hempseed oil is a drying oil, formerly used in paints and varnishes and in the manufacture of soap. Present cultivation of oilseed hemp is not competitive with linseed for production of oil for manufacturing, or to sunflower and canola for edible vegetable oil. However, as noted below, there are remarkable dietary advantages to hempseed oil, which accordingly has good potential for penetrating the salad oil market, and for use in a very wide variety of food products. There is also good potential for hemp oil in cosmetics and skin-care products.
Selective breeding of cannabis plants has expanded and diversified as commercial and therapeutic markets develop. Some growers in the U.S. succeeded in lowering the proportion of CBD-to-THC to accommodate customers who preferred varietals that were more mind-altering due to the higher THC and lower CBD content.[58] Hemp is classified as any part of the cannabis plant containing no more than 0.3% THC in dry weight form (not liquid or extracted form).[59]
Fig. 2. Cannabis sativa. This superb composite plate by artist Elmer Smith, often reproduced at a very small scale and without explanation in marijuana books, is the best scientific illustration of the hemp plant ever prepared. 1. Flowering branch of male plant. 2. Flowering branch of female plant. 3. Seedling. 4. Leaflet. 5. Cluster of male flowers. 6. Female flower, enclosed by perigonal bract. 7. Mature fruit enclosed in perigonal bract. 8. Seed (achene), showing wide face. 9. Seed, showing narrow face. 10. Stalked secretory gland. 11. Top of sessile secretory gland. 12. Long section of cystolith hair (note calcium carbonate concretion at base). Reproduced with the permission of Harvard University, Cambridge, MA.

The scientific debate regarding taxonomy has had little effect on the terminology in widespread use among cultivators and users of drug-type Cannabis. Cannabis aficionados recognize three distinct types based on such factors as morphology, native range, aroma, and subjective psychoactive characteristics. Sativa is the most widespread variety, which is usually tall, laxly branched, and found in warm lowland regions. Indica designates shorter, bushier plants adapted to cooler climates and highland environments. Ruderalis is the informal name for the short plants that grow wild in Europe and Central Asia.