Growers, medicinal users, and ordinary decent stoners need to know the anatomy of the cannabis plant. Just like fresh fruit and vegetables, it pays to know the basics. Otherwise, you might return home from shopping with green bananas and rotten tomatoes.

You don’t need a degree in botany, but it helps to know some phytotomy essentials. Like, if you’re wasting your time cultivating male plants or how to spot a hermaphrodite. Or if you’ve been wondering what exactly is a calyx anyway? All this and more we shall endeavour to answer.

Let’s take a look at all the parts of the cannabis plant from root to flower. Plus, we will explain every part's function in relatable terms.


Cannabis Roots

Beneath the surface of the growing medium, the roots are busy simultaneously anchoring and drawing nutrients into the cannabis plant. The root zone consists of a single tap root, that will develop many secondary roots until it becomes a fibrous mass.

Roots are part of the vascular system of the cannabis plant. Internally the xylem is responsible for pumping water and minerals from the roots to the rest of the plant. Think of the xylem as the marijuana plumbing system.


Cotyledon Leaves

A cotyledon is an embryonic leaf that occurs in seed-bearing plants. Cotyledons are formed during embryogenesis alongside root and shoot meristems. This primordial growth is the first leaf set to appear after germination takes place. The green appearance of cotyledons is an indication of the presence of chlorophyll, allowing the small leaves to conduct photosynthesis in the early stages of growth. Soon after, the first set of true leaves will emerge. Cannabis is classed as a dicotyledon, a flowering plant with an embryo that bears two cotyledons. However, abnormal growth can lead to the growth of 3 or even 4 cotyledons.


Cannabis Stem

The main stem emerges from the root and supports the cannabis plant growing vertically. Naturally, the stem is the primary vascular highway, carrying the water and minerals from the roots. It’s also integrated with the phloem, to be discussed later. Secondary growth emerges from the main stem from what is called a leaf node.

Branching occurs in pairs from a leaf node on either side of the stem. The distance between sets of branches is referred to as the internode spacing. Generally, indica-dominant varieties have shorter internode spacing than sativa-leaning varieties.

Occasionally, mutations can give rise to irregular branching. Mutant cannabis plants can still be potent and productive, although most growers remove them immediately. We say if they look healthy, live and let live.


Cannabis Fan Leaves

Fan leaves also adhere to symmetry and grow in pairs from the main stem and branches. The fan leaves also help to distinguish between indica and sativa marijuana. Dark, wide leaves for indica and light green, lean slender fingers for sativa’s, is the rule of thumb. Hybrids are a blend of the two.

More importantly, the fan leaves act like the solar panels of the cannabis plant. They soak up all the light available, and internally the phloem transports the energy throughout the rest of the plant. Think of the phloem as similar to the electrical wiring in the walls of your home.

Fan leaves are essential to photosynthesis and should never be pruned excessively. Shade leaves can be removed late in bloom if blocking lower bud sites.


Cannabis Male and Female

A cola is simply the flowering top of the female cannabis plant. Of course, topping or the application of LST or the ScrOG method will give rise to multiple tops. Nevertheless, the main top buds are all considered colas. Buds and nuggs are simply cover-all terms for all flowers, that emerge from bud sites throughout the stems. Look for a white hair emerging from the leaf node in pre-flower to confirm a female cannabis plant.

Male plants do not produce bud when they flower, which is usually a couple of weeks sooner than females. The male cannabis plants will not necessarily be the largest, most vigorous plants in the garden either. Males produce stamens with anthers packed with pollen.

It is always wise to postpone jumping to conclusions until pre-flowers can be discerned. If the white hair is absent and a cluster of grapes begins to protrude, then a male is present.


Cannabis Calyx

Buds are not just a tangled mess of leaves and gooey resin. Calyxes are the tiny clusters shaped like a tear drop, that constitutes a cannabis bud. Leaves will grow from between and around the calyxes. The elusive **calyx is most visible to the naked eye in the later stages of flowering as buds begin to swell.

Only non-pollinated flowers bloom abundantly. Should the pistil get pollinated, then the calyx below becomes the ovary. This changes the function to seed incubator.

Some buds can be really hard with compact groupings of many tiny calyxes; others can have larger calyxes in a looser formation. Generally, indica influence is what gives most cannabis its tight appearance. Only heirloom landrace pure sativa strains produce a very airy wispy flower.


Cannabis Pistils

Pistils are what are commonly known as the “hairs” on nuggs. Pistils help you identify female plants in the cannabis garden. Prior to flowering, females will display the odd pistil from leaf nodes to tip off the grower.

During the flowering period, they will transition in colour from white to orange/red as the bud ripens. These pistils are actually the female plant’s reproductive organs containing the ovules.

The pistils are primarily outgrowths from calyxes and essentially serve to capture pollen. The female cannabis plant wants to be fertilised and so long as she is denied this during bloom, flower production will be her focus.


Cannabis Resin

Trichomes are the glistening gooey resinous coat, that covers all fine cannabis buds. As flowering progresses, calyxes and surrounding sugar leaves will become covered in fields of tiny mushroom capped stalks. These heads will transition in colour from clear to white to amber during blooming.

The trichs are what it’s all about, because these are the microscopic cannabinoid factories, that give cannabis buds the effects we all know and love. Hashish and all of your favourite concentrates are extracted trichomes.


There will be trouble in the ganja forest if pollen gets into the pistils of flowering female cannabis plants. Moreover, male cannabis plants have stamen instead of pistils and they produce pollen sacs, that contain, you guessed it, pollen.

These anthers or pollen sacs will hang down and are usually green/yellowish in colour. Hermaphrodites display these green/yellowish pollen sacs too, usually popping out amongst clusters of flowers. These are what we call “nanners”.

If a plant displays pollen sacs, it must go immediately or the rest of the weed will be seeded. Identify and remove males/hermies post-haste. Stress can be a contributory factor to the emergence of intersex traits, so make sure the grow op is dialled in.


External Resources:
  1. Cannabis Pharmacology: The Usual Suspects and a Few Promising Leads - PubMed
This article has been written for informational purposes only, and is based on research published by other externals resources.

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