Hey, bro! Some mutants have ordinary leaves, but the stem widens and becomes flat.
In the cannabis community, it is often called a “polyploid,” although a flat stem cannot tell you the chromosome number.
Fasciation has a long botanical history, and cannabis entered it long before today’s mutant collections. This history has specific authors and dates.
What happens at the tip
Its size and organization influence how future organs will be arranged.
The stem may become broad and flattened, bend, twist, or divide into several extensions.
They also list several possible causes of disruption to the terminal bud: damage, mutations, inherited characteristics, and infections. Pacific Northwest Plant Disease Management Handbook
An oddity from the seventeenth century
In 1665, Johann Daniel Major published De planta monstrosa Gottorpiensi, a work about an unusual plant from Gottorp. Maxwell Masters later referred to it when discussing the fasciated stem of a plant called Chrysanthemum. A digitized title page of Major’s publication survives. Title page from 1665, Masters on early descriptions
Molecular genetics was still centuries away.
Such plants were described separately because they did not fit the simple picture of how a normal shoot is built.
This is a history of general botany, and there is no cannabis in Major’s work. It shows that such deviations were already being described in the seventeenth century.
Masters, 1869
In 1869, the British botanist Maxwell Tylden Masters published Vegetable Teratology.
In the fasciation section, Masters described ribbon-like stem expansion, longitudinal ridges, bending, and division of the tip. The illustrations included lettuce, asparagus, pine, and dandelion. He also compared older explanations: whether several parts merge or a single shoot flattens. Vegetable Teratology, Fasciation section
Masters was already separating the visible result from the process that led to it.
He also discussed cases in which the trait recurred in offspring, for example in Celosia. Fasciation can be hereditary, but not always.
Crescini, 1934
In 1934, Francesco Crescini published the paper Sulla fasciazione della canapa (Cannabis sativa L.), “On the fasciation of hemp.” It occupies pages 387–389 of a botanical journal.
Major and Masters wrote about general botany. Crescini’s paper is a separate scientific work on fasciation specifically in cannabis.
The trait in cannabis was described in the scientific literature long before today’s interest in mutants.
Crescini’s paper was included in the bibliography of Orland White’s extensive 1948 review. White, Fasciation, reference to Crescini’s paper
White’s review and the genes
In June 1948, Orland F. White published the review Fasciation in Botanical Review. The forty-page work brought together a substantial body of earlier publications. By mid-century, fasciation was a broad subject in botany. Bibliographic record of the review
Later, researchers moved from describing shape to individual genes. In 1993, Steven Clark, Mark Running, and Elliot Meyerowitz studied CLAVATA1 in Arabidopsis. CLAVATA1, a regulator of meristem and flower development
In 2001, Fumio Taguchi-Shiobara and colleagues described fasciated ear2 in maize. Disruption of this gene’s function was accompanied by excessive growth of the ear meristem. Study of fasciated ear2
This gave fasciation molecular explanations. Different plants were used to study different parts of the system that controls growth: CLAVATA1 was described in Arabidopsis, fasciated ear2 in maize.
Fasciation and polyploidy
A flat, thick stem is often called polyploid: the plant looks as though it has been given “more of everything.”
Polyploidy is an increase in the number of complete sets of chromosomes. Fasciation is a change in the organization of growth.
Cannabis in its ordinary diploid state has 20 chromosomes. A different set is established by cytological or genomic analysis. Biology of Cannabis sativa, CFIA
Different deviations can occur on the same plant. But a broad bud, a three-leaf arrangement, or a split tip does not on its own show a doubled genome: known mechanisms of fasciation work through the meristem.
In forum language, “polyploid” is a name for how a plant looks.
Fasciation from infections
Oregon surveys in 2021–2022 recorded leaf deformation, chlorotic mosaic, and fasciation among the symptoms. First report of Spiroplasma citri
In 2026, Camille Wagstaff and coauthors reported detecting “Candidatus Phytoplasma trifolii” and Spiroplasma citri in Washington State hemp. Material was collected in 2022 and 2024, and stem fasciation was again among the reported signs. The researchers noted that mixed infections make it harder to link a symptom to a particular pathogen. Report from USDA ARS and Washington State University
A flattened tip can also be a symptom of disease.
In these studies, pathogens were confirmed in the lab from samples.
The mutant.farm archive
The mutant.farm archive contains a photograph of fasciation in Lowryder.
Fasciation is identified by widening and flattening of the axis or the tip.
Ordinary cannabis also shows different ways of ending an inflorescence: the apical meristem either keeps developing or ends in a flower. A stopped tip is not fasciation in itself. Study of cannabis architecture, 2019
Common questions
The phenomenon has no single author. There are authors of publications and people who noticed particular plants. An early scientific paper on fasciation in cannabis is Crescini’s 1934 article.
Is fasciation always genetic?
No.
Does a flat stem mean polyploidy?
No. Chromosome number and meristem organization are different characteristics. Polyploidy is determined from data on the chromosome set.
If one branch is altered, is it a separate cultivar?
No. An altered branch is an observation on one plant. A line appears when the trait recurs in offspring, as with Celosia in Masters’s descriptions.
Do all photos of unusual buds show fasciation?
No. A dense bud, an unusual outline, or stopped growth is not fasciation.
The bottom line
The history of fasciation is Major’s 1665 work, Masters’s 1869 book, Crescini’s 1934 paper on hemp, and studies of meristems. Data on pathogens and amateur photographs came later.
Botanists have their own name for a flat stem: fasciation.