The head, the stalk, and what breaks between

What is bought in a flower is not the flower. It is the contents of a few hundred thousand microscopic glands sitting on its surface, the largest of which is about a tenth of a millimetre from base to crown.

Those glands have a stalk, a head, a membrane and a contents that differs depending on when you look at them. They also shear off at almost any contact — against a bag, through a grinder, between fingers, in a parcel.

This page describes what they are, how they are built, what they make, why the colour changes, what their fragility means for everything downstream, and what a laboratory report retains of any of it.

⚠️ Scope. This page describes a process and what can be verified from documents. It does not describe what a product does to a person, gives no amounts, and does not replace a healthcare professional.

🔴 What a trichome is

The word

From the Greek for hair. In botany it denotes any outgrowth of the plant epidermis, and thousands of species carry them for purposes that have nothing to do with this one.

The distinction that matters here

Some trichomes on this plant are not simple hairs but glands. They synthesise and store a contents kept apart from the rest of the tissue by a membrane, which is what makes them interesting.

Why the separation matters

What the plant makes there does not circulate in the sap. It sits in an external pocket, which explains both the concentration of the material and how easily it is lost.

The three forms

Bulbous, at ten to fifteen micrometres. Capitate sessile, at twenty to thirty. Capitate stalked, at fifty to a hundred — and it is the last that carries the great majority of what is sought.

The capitate stalked gland

The stalk

A column of cells raising the head above the epidermis. That height is exactly what makes the gland accessible for separation and vulnerable to everything else.

The secretory disc

A ring of cells at the base of the head produces the contents and pushes it upward. This is the factory proper, and it is the only part that is metabolically active.

The cuticle

A thin membrane lifts above the disc and forms a pocket. The contents accumulates beneath it, under pressure, until harvest or until something breaks it.

The whole structure

A pressurised balloon on a thin column, with no rigid protection anywhere. Described that way, its fragility stops being surprising.

What is made inside

The starting material

The plant assembles two building blocks from separate metabolic pathways into a single precursor molecule, and everything else follows from that one compound.

The acid forms

In the living plant the cannabinoids exist as acids: CBDA, THCA, CBGA. These are what the gland actually contains, and the neutral forms appear only later.

The terpenes alongside

The volatile compounds responsible for aroma are made and stored in the same pocket. This is why aroma and potency travel together physically while being chemically unrelated.

What this means for analysis

Extracting the contents of the glands is what an analysis does. It does not distinguish which gland any molecule came from, and it does not need to.

🔴 Why they break so easily

The mechanics

A swollen head on a fine stalk, with a membrane under tension. There is no structural reinforcement at any point in the assembly.

What is enough to detach them

Friction against a bag, a hand passing over the surface, compression in an overfilled jar, a fall. Each contact takes a fraction.

Where the contents goes

Onto container walls, onto fingers, to the bottom of a bag. The pale powder that accumulates in the base of a jar is detached heads.

What this changes about the product

The material has not disappeared, it has moved. It is simply no longer on the flower being held, which is where it was paid for.

Colour and what it indicates

Clear

The gland is still filling. The contents has not reached its maximum density and synthesis continues.

Cloudy

The contents has thickened enough to scatter light. This is the state sought at harvest: the synthesis has produced what it is going to produce.

Amber

The neutral forms are beginning to degrade. A proportion converts, the aroma shifts, and the composition is no longer what it was a week earlier.

What a grower reads

The proportion between the three states across several points on the plant, never a single head. A harvest date is decided on an observed percentage.

What colour does not indicate

Any content figure

A cloudy head does not say whether a batch runs at four per cent or twelve. It says the filling is advanced, not how far.

Any aroma profile

Two flowers at identical visual stages can have entirely different terpene profiles. The eye does not separate them.

Any compliance position

Total THC — delta-9-THC plus THCA multiplied by 0.877 — is not visible. It is calculated from a laboratory report and from nothing else.

What replaces it

A batch certificate from a laboratory accredited to ISO/IEC 17025. Nothing else performs that function.

Density and yield

What density measures

Glands per unit of surface. It depends on genetics, on the light the plant received, and on how the crop was managed.

Why it is not sufficient

A plant can carry many small glands or fewer large ones. What matters is total volume, not the count.

What a frosted appearance shows

A high density of stalked glands that have reached full size. It is a good sign and it is only a sign.

What settles it

The line on the certificate, giving a mass percentage measured on the specific batch being bought.

Where they are on the plant

On the bracts

The highest density is on the small leaves enveloping the flowers. This is where the plant concentrates its effort.

On the nearby leaves

The immediately adjacent leaves carry them too, at lower density. These are recovered at trimming and usually go elsewhere.

On the large leaves

Almost nothing usable. They carry mostly non-glandular trichomes, which produce none of this contents.

What this decides about trimming

Removing too much removes glands; removing none leaves plant material of no interest. The compromise is judged by eye.

The non-glandular kind

What they do

They are simple hairs, with no head and no cavity. They make nothing. Their role is mechanical: slowing evaporation, obstructing insects, breaking airflow at the leaf surface.

Where they are

Everywhere, and predominantly on the large leaves and stems. They are what gives the plant its slightly rough feel.

Why distinguishing them matters

At low magnification they resemble the others. A leaf covered in hairs can look rich and contain nothing at all.

The sign that separates them

The absence of a round head at the tip. Under a decent loupe the difference is immediate: a tapered hair on one side, a balloon on a stalk on the other.

What separation exploits

The principle

The fragility is used deliberately: chill the material, agitate it, and the heads detach and pass through a calibrated mesh.

What is obtained

A concentrated powder of gland heads and fragments. Its composition depends directly on the fineness of the mesh used.

Why mesh size matters

Too coarse and plant debris passes with the heads. Very fine and only the heads are retained, in smaller quantity.

What this implies at purchase

A concentrate concentrates everything, including what should not be there. The contaminant lines of a report carry more weight on an extract than on a flower.

What drying does to them

Water loss

The flower loses most of its mass as water. The glands contain almost none, so their proportion of the remaining mass rises mechanically.

Stiffening

A dried stalk is more brittle than a fresh one. This is why dried material sheds heads faster than material just cut.

The role of speed

A fast dry fixes the glands before the volatile compounds have equilibrated. A slow dry between fifteen and twenty degrees retains more of them.

What gets measured afterwards

Every figure on a certificate is expressed on a dry basis. It is the only convention that lets two batches be compared without moisture distorting the result.

What a report keeps of all this

What is measured

The cannabinoids, as a percentage of mass. The method extracts the gland contents and quantifies it, without distinguishing origin.

What never appears

The number of glands, their size, their filling state, the proportion sheared off. None of it is on a certificate.

The limit of quantification

Below a threshold the laboratory does not give a figure and writes LQ. That means below the measurable threshold, not zero.

What the document genuinely supports

Comparing two batches on a common basis, and verifying that the calculated total sits within the applicable limit. Nothing further.

Looking at them yourself

The instrument

A jeweller’s loupe at thirty to sixty times is enough. A pocket microscope with its own light does better and costs little.

The technique

Set the flower down rather than holding it, and light it from the side. Raking light brings out the stalks and the outline of the heads.

What to look for

The proportion of cloudy heads against clear and amber ones, across several points rather than one, and whether the heads are still on their stalks.

What not to look for

Confirmation of a stated content. An observation is not a measurement, and nobody should buy on that basis.

What genetics fixes and what it does not

The count and the size

Two varieties grown side by side, under identical conditions, produce neither the same number of glands nor the same head size. This is inherited and it is the largest single factor.

The composition of the contents

The ratio between CBDA, THCA and CBGA is set by the variety. It is why some entries in the European common catalogue remain compliant and others could not.

The aromatic profile

The terpenes sit in the same pocket, and their assortment is likewise genetic. It changes completely from one variety to another.

What follows for comparison

Comparing gland density between two different varieties means very little. The comparison is only sound between two batches of the same variety.

What light changes

The intensity received

The most exposed tops carry a higher gland density than the lower parts of the same plant. The difference is visible without magnification.

The practical consequence

One plant yields flowers of unequal quality. Tops and lower material are not sold at the same price, and that is justified.

The role of crop management

Spreading the canopy, opening the branches, evening the heights — all of it serves to expose more tops to the same light.

What it does not change

The genetic profile. Light acts on how much is produced, not on the nature of what is produced.

The scale problem

What a tenth of a millimetre means

At the size of the largest gland, roughly two hundred could sit end to end across a fingernail. Nothing about them is visible unaided beyond the collective glitter they produce.

Why this matters to a buyer

Every judgement made by eye about a flower is a judgement about an aggregate. Individual glands, their integrity and their state can only be assessed with magnification, and almost nobody does it.

What the instrument costs

A loupe at thirty times is a few euros and fits in a pocket. It is the cheapest item in this entire subject and the one that shows the most that is otherwise invisible.

A short glossary

Trichome

An outgrowth of the plant epidermis. Glandular when it secretes, non-glandular when it does not.

Capitate stalked

A trichome with a round head carried on a stalk. The form containing most of the material sought.

Cuticle

The outer membrane lifting above the secretory disc and retaining the contents under pressure.

Acid form

The state in which cannabinoids exist in the living plant: CBDA, THCA, CBGA.

Total THC

Delta-9-THC plus THCA multiplied by 0.877. The sum to which regulatory limits apply.

The five checks that apply to any product

The batch certificate

Request it with the number printed on the packaging. A general document for the product line does not cover this batch, and those differences are exactly what it should record.

Total THC

Delta-9-THC plus THCA multiplied by 0.877, because THCA becomes THC under heat and the limit applies to the sum, not to either value alone.

Price per milligram

A division, not an opinion. The only figure that makes two products comparable, whatever the format, process and pack size.

The claims

Without an authorisation number in the EU Register these are assertions, not data — and for cannabidiol that register contains no authorised entry to this day.

The seller’s details

Company name, address and contact. Without them there is also no counterparty to turn to if something turns out to be wrong.

How this connects to the rest

With storage

An over-handled flower loses its heads before it is used. The rigid container and the moderate fill level exist for this reason alone.

With trimming

Trimming decides how many glands leave with the leaves. A careful trim retains more than an aggressive one.

With harvest timing

Head colour is the principal indicator of when to cut. It continues shifting afterwards, more slowly, in the jar.

With concentrates

The whole family of mechanical separations rests on this fragility. Without it, a solvent would be required.

What this is for in practice

For looking at a flower

Look for the heads rather than the overall colour. A dull flower well supplied beats a bright one that is bare.

For judging packaging

A soft bag filled to the top sheds glands at every handling. A jar half full sheds far fewer.

For reading a report

Remember that the percentage covers what remained at sampling. What was lost afterwards is not in it.

For comparing two offers

Appearance does not compare between sellers. The batch certificate does.

Frequently asked questions

How big is a trichome? From ten micrometres for a bulbous one to a hundred for a capitate stalked one — a tenth of a millimetre at most.

Which type holds the material? The capitate stalked form, overwhelmingly. The other two contribute very little.

Does colour indicate content? No. It indicates a filling or degradation stage, never a percentage.

What does a cloudy head mean? That the contents has thickened. This is the state generally sought at harvest.

What does an amber head mean? That the neutral forms are beginning to degrade. A few are normal; a majority indicates a late harvest.

Why do they break so easily? Because a swollen head sits on a fine stalk with no protection around it.

Where does what detaches go? To the bottom of the container, onto the walls and onto fingers. It is the pale powder found in a jar.

Can they be seen without an instrument? The frosted appearance is visible unaided. The shape of the heads needs thirty times magnification at minimum.

Does a report describe them? No. It gives contents, not a description of the glands or their condition.

Is a very frosted flower stronger? Not necessarily. Density is an indication; only the certificate gives a figure.

What we check and what we do not

We check what can be checked from documents: official registers, declared contents, certificates of analysis, arithmetic. We test no products, rank nothing, and assert no effects.

The peculiarity of this subject is that it sits entirely below the threshold of what a buyer can inspect. A frost can be seen, a content cannot; a stage can be guessed at, a compliance position cannot. Everything that is actually decided is decided in a laboratory.

What remains within reach is modest and useful: a loupe costing a few euros, the habit of looking at the heads rather than the overall colour, and the reflex of asking for the batch certificate for everything else.