Cannabis is a flowering plant in the family Cannabaceae, the same botanical family as hops. Formally classified as Cannabis sativa L. by Carl Linnaeus in 1753, it is one of the oldest cultivated plants in human history, grown for its psychoactive resin, nutritious seeds, and strong stem fibers. The plant contains over 500 chemical compounds, including at least 104 identified cannabinoids, and its uses range from medicine and recreation to textiles and construction materials.
Taxonomy and Main Varieties
All cannabis belongs to a single species, Cannabis sativa L., but DNA analysis supports at least two recognized subspecies: C. sativa subsp. sativa and C. sativa subsp. indica. In everyday language, these are the “sativa” and “indica” types you see labeled on products, though the real chemical differences between individual plants are more nuanced than those two labels suggest.
Sativa-type plants tend to grow tall with thin, narrow leaves and a longer growing season. Indica-type plants are shorter, with broader leaves and a woodier stalk. These physical traits matter to growers choosing varieties for specific climates or indoor setups, but the chemical profile of a given plant depends more on its particular genetics and growing conditions than on whether someone calls it sativa or indica.
Anatomy of the Plant
Cannabis is dioecious, meaning individual plants are either male or female. This distinction is central to how the plant is cultivated. Female plants produce dense clusters of flowers (often called “buds”) that are rich in cannabinoids and terpenes. Male plants produce pollen sacs instead. If a male pollinates nearby females, the female flowers shift energy toward seed production and their cannabinoid concentrations drop. For this reason, commercial growers remove male plants and keep only unpollinated females when the goal is potent flower.
The most important structures on the female flower are tiny, hair-like projections called glandular trichomes. These trichomes sit mostly on the flower’s surface and surrounding small leaves, and they function as miniature chemical factories. The sticky resin they produce contains the plant’s cannabinoids, terpenes, and flavonoids. The capitate stalked trichome is the most abundant type on the plant and the primary source of the resin that gives cannabis its effects and aroma.
Key Cannabinoids: THC and CBD
Of the 104-plus cannabinoids identified in cannabis, two dominate the conversation. THC (tetrahydrocannabinol) is the main psychoactive compound. It produces the intoxicating feeling most people associate with cannabis use. A plant’s potency is primarily measured by its THC concentration.
CBD (cannabidiol) works very differently. It does not produce euphoria and in many ways acts as THC’s counterpart. Research indicates CBD has anti-anxiety, anti-inflammatory, and antiepileptic properties. It may also buffer some of THC’s negative psychological effects, which is why the ratio of THC to CBD in a given product matters to users.
These compounds work by interacting with the body’s endocannabinoid system, a network of receptors found throughout the brain and body. Your body naturally produces its own cannabinoid-like molecules that plug into these receptors to help regulate mood, pain, appetite, and memory. THC mimics those natural molecules and binds directly to the same receptors, which is why its effects are so pronounced. CBD, by contrast, has very little direct binding affinity for those receptors. Instead, it appears to work indirectly, modulating how the receptors respond and influencing the effects of THC when both are present.
Terpenes and Aroma
The distinctive smell of cannabis comes from terpenes, aromatic compounds produced alongside cannabinoids in the trichomes. Cannabis contains dozens of terpenes, and their combination gives each variety its unique scent profile.
Myrcene is typically the most abundant terpene in cannabis, contributing earthy, musky notes with hints of cloves. Limonene adds a bright citrus scent. Pinene smells like a pine forest. Linalool gives a floral, lavender-like quality. Caryophyllene delivers a peppery, spicy warmth. These terpenes are not unique to cannabis. Myrcene is found in mangoes, limonene in lemon rinds, and linalool in lavender. Many researchers and users believe that the specific combination of terpenes and cannabinoids in a plant shapes the overall experience more reliably than the sativa/indica label does.
Growth Cycle From Seed to Harvest
Cannabis is an annual plant, completing its full life cycle in one growing season. That cycle breaks down into distinct stages, each with a rough timeline:
- Germination: 3 to 10 days. The seed cracks open and a taproot emerges.
- Seedling: 2 to 3 weeks. The first recognizable cannabis leaves appear, and the plant is fragile.
- Vegetative growth: 2 to 8 weeks. The plant focuses on building stems, branches, and leaves. Light exposure drives this phase, and indoor growers can extend or shorten it by controlling how many hours of light the plant receives each day.
- Pre-flowering: 1 to 2 weeks. The plant reveals its sex, showing either tiny pollen sacs (male) or white hair-like pistils (female).
- Flowering: 6 to 8 weeks. Female plants develop resinous buds as trichome production ramps up. This is when cannabinoid and terpene concentrations peak.
From seed to harvest, the full process takes roughly 3 to 7 months depending on the variety and growing conditions.
Hemp vs. Marijuana: A Legal Line
Biologically, hemp and marijuana are the same plant. The distinction is entirely legal and based on one number: THC content. In the United States, cannabis with 0.3% THC or less on a dry weight basis is classified as hemp and is not a controlled substance. Cannabis above that threshold is classified as marijuana and remains federally regulated. That 0.3% cutoff, established by the 2018 Farm Bill, opened the door for widespread hemp cultivation across the country.
Hemp varieties have been bred specifically to stay below that limit. They tend to be high in CBD and fiber, with minimal THC. Marijuana varieties, by contrast, have been selectively bred to maximize THC for recreational or medical use.
Industrial and Commercial Uses
Cannabis grown as hemp is one of the most versatile crops in agriculture. The plant’s stem bark produces long, strong fibers used to make rope, textiles, paper, and garments. Those fibers have enough tensile strength to serve as reinforcement in packaging materials and biocomposites. The woody core of the stalk, called hurd, is a byproduct of fiber extraction and gets pressed into particle board or processed into biodegradable plastics.
Hemp seeds are another valuable product. They yield oil used in food products and cosmetics, and the leftover seed cake is rich in protein, making it an effective supplement in animal feed. Hemp seeds also show up in birdseed mixes and as fish bait. On the other end of the spectrum, cannabis grown for its cannabinoid content supplies the medical and recreational markets, with products ranging from dried flower to concentrated oils and edibles.