Dendranthema vs Chrysanthemum: Plant Genetics and Chemistry

Dendranthema is a botanical name for the group of plants most people simply call chrysanthemums, particularly the cultivated garden and florist varieties that rank among the world’s most commercially important ornamental flowers. The name has been at the center of one of horticulture’s most contentious taxonomic disputes, with scientists and industry professionals spending decades arguing over whether these plants belong in the genus Chrysanthemum or the genus Dendranthema. That argument has technically been settled in favor of Chrysanthemum, but the name Dendranthema persists widely in scientific literature, plant databases, and nursery catalogs, and understanding why requires a look at the biology, chemistry, and surprisingly rich practical applications of these plants.

Why Two Names Exist

The confusion traces back to the late 20th century, when taxonomists split the old, sprawling genus Chrysanthemum into several smaller genera based on morphological and genetic differences. The cultivated florist’s chrysanthemum and its close wild relatives were moved into a new genus called Dendranthema. For about two decades, the “correct” scientific name for the garden mum was Dendranthema grandiflorum (sometimes written Dendranthema × grandiflorum to indicate its hybrid origin). Researchers published under this name, plant breeders adopted it, and it entered trade regulations around the world.

Then, in 1999, the International Botanical Congress voted to conserve the name Chrysanthemum for the florist’s chrysanthemum group, effectively reversing the split. The accepted name reverted to Chrysanthemum morifolium (or Chrysanthemum × morifolium). Despite this, thousands of published papers, cultivar registrations, and phytosanitary documents still use Dendranthema, and you will encounter it routinely when reading anything about chrysanthemum genetics, breeding, or chemistry from the 1990s through the early 2010s. Some journals continued using it well into the 2020s. The two names refer to the same group of plants, and in practice they are interchangeable in most contexts you are likely to encounter.

A Genetically Complex Plant

One reason chrysanthemum taxonomy has been so difficult to sort out is that these plants are genetically complicated. The cultivated chrysanthemum is a hexaploid, meaning it carries six copies of each chromosome set rather than the usual two found in most organisms. Early molecular work on chrysanthemum using DNA-based markers found that this hexaploid character produced complex banding patterns, with roughly six to twelve fragments visible per probe on laboratory blots.¹ This level of genetic redundancy makes traditional breeding analysis far harder than in simpler crops. It also means that chrysanthemum cultivars can harbor enormous genetic diversity, which partly explains the staggering range of flower forms, colors, and sizes available commercially.

The phylogenetic relationships between cultivated chrysanthemum and its wild relatives remain only partially resolved. Despite advances in DNA sequencing, the origin of different cultivated varieties and how the genus relates to nearby groups within the daisy family are still considered elusive.² Wild species such as Chrysanthemum indicum, C. zawadskii, and C. boreale are thought to be ancestral contributors, but the hybridization history spans thousands of years of cultivation, mostly in China and Japan, and untangling it genetically is an ongoing project.

What Controls When They Flower

Chrysanthemums are famously photoperiod-sensitive. Most cultivars are short-day plants, meaning they initiate flowering when nights grow long enough in autumn. This trait is what makes them the quintessential fall flower in temperate climates, and it is also what allows greenhouse growers to force blooms year-round by manipulating light exposure.

At the molecular level, the picture is more nuanced than “short days trigger flowering.” Transcriptomic studies of summer-flowering chrysanthemum varieties have revealed that under short days, genes in the photoperiod and gibberellin pathways accelerate the transition to flowering, while under long days, different sugar-signaling pathways are promoted and a phytochrome pathway actively blocks the flowering response.³ In practical terms, this means chrysanthemum flowering involves a tug-of-war between promoting and inhibiting signals, not a single on/off switch. Breeders have exploited this complexity to develop varieties that bloom at different times of the year, including day-neutral types that flower regardless of light schedule.

The Chemistry Inside the Flowers

Beyond their ornamental value, Dendranthema species produce a rich cocktail of biologically active compounds. The aromatic wild chrysanthemum D. indicum var. aromaticum (now more commonly written under Chrysanthemum) has been analyzed for its phenolic content, with researchers identifying 14 phenolic compounds including eight phenolic acids and six flavonoids. Some of these compounds, including oleuropein derivatives, chrysoeriol, and tricin, had not previously been reported in this variety.⁴ These flavonoids and phenolic acids are the same broad categories of antioxidant compounds found in green tea, berries, and other foods linked to anti-inflammatory effects.

The volatile chemistry is equally interesting. A comparative analysis of white standard chrysanthemum (Dendranthema grandiflorum) flowers from different growing regions identified 41 volatile organic compounds, dominated by monoterpenoids, sesquiterpenoids, alcohols, and fatty acids.⁵ These volatiles are what give chrysanthemum flowers and leaves their characteristic herbal, slightly camphor-like scent. The volatile profile varied by growing region, which matters commercially: chrysanthemum flowers destined for tea production or traditional medicine carry flavor and aroma signatures tied to their origin, much like wine grapes.

Chrysanthemum in Traditional Medicine and Modern Pharmacology

Chrysanthemum flowers have been used in Chinese, Korean, and Japanese traditional medicine for centuries, most commonly brewed into tea. Modern laboratory research has started to put some specificity behind these traditional uses, though it is worth emphasizing that most findings are from cell cultures or animal models rather than clinical trials in humans.

One area with consistent laboratory evidence is liver protection. An extract from Chrysanthemum morifolium (the Boju variety) prevented liver injury caused by alcohol, carbon tetrachloride, and acetaminophen in cell and animal models. The protective mechanism appeared to work through activation of the Nrf2 signaling pathway, which ramps up the cell’s own antioxidant defenses.⁶ A separate study found that a water extract of C. morifolium reduced fatty liver, high blood lipids, and markers of liver damage in rats with combined metabolic and alcohol-associated liver disease, with improvements in gut microbial balance and reductions in inflammatory markers like TNF-α and IL-6.⁷

Anti-inflammatory effects have been documented for wild chrysanthemum (Chrysanthemum indicum) as well. An ethanol extract strongly inhibited production of several inflammatory molecules in stimulated immune cells, in a dose-dependent fashion, and suppressed a key inflammatory signaling pathway.⁸ A related species, Dendranthema oreastrum, showed protective effects against acute lung injury in a mouse model, reducing oxidative stress and dampening inflammasome activity in lung tissue.⁹

These findings point to a family of plants whose chemical profiles consistently show antioxidant and anti-inflammatory potential. Whether that translates into meaningful health benefits from drinking chrysanthemum tea is a different question, and one that human clinical trials have not yet adequately answered. The doses used in laboratory studies are typically much higher, in concentrated extract form, than what anyone would consume by steeping dried flowers in hot water.

The Pyrethrin Connection

One of the most economically significant products ever derived from a chrysanthemum relative is pyrethrin, a natural insecticide. Pyrethrins come from Tanacetum cinerariifolium, a species that was historically grouped with chrysanthemums and is still closely related within the daisy family. These compounds attack the nervous systems of insects while being relatively low in toxicity to mammals, which made them the basis for one of the world’s most widely used classes of insecticides. The synthetic versions, called pyrethroids, now dominate the market, but natural pyrethrins are still prized in organic agriculture and household pest control.

The natural pyrethrin content in T. cinerariifolium flower heads is low, which has driven research into how to boost it. Scientists recently identified a key transcription factor, TcbHLH14, that directly activates genes involved in pyrethrin production. When this factor was overexpressed in plants, pyrethrin-pathway genes ramped up; when it was silenced, pyrethrin content dropped.¹⁰ This kind of work could eventually lead to higher-yielding pyrethrin crops, reducing dependence on synthetic alternatives.

Flower Color and the Quest for True Blue

Chrysanthemums come in an extraordinary range of colors: white, yellow, bronze, pink, red, purple, and green. The pigments responsible for the pink-to-purple spectrum are anthocyanins, the same class of compounds that color blueberries, red cabbage, and autumn leaves. In chrysanthemum, the biosynthesis of anthocyanins in ray florets has been well studied at the gene level, but the genetic and environmental control of exactly which color appears in a given flower remains only partially understood.¹¹ Environmental factors like temperature and light intensity can shift flower color even within a single cultivar, which is a persistent headache for growers aiming for consistent product.

One color that chrysanthemums cannot naturally produce is true blue. The anthocyanin pathway in chrysanthemums does not produce delphinidin-based pigments, which are the ones responsible for blue hues in other flowers. Researchers have attempted to introduce blue color through genetic engineering, with some partial success involving genes from other plant species, but a commercially viable true-blue chrysanthemum remains a work in progress. The difficulty of achieving blue through pigment engineering is a well-known challenge across the floral industry, not unique to chrysanthemums.

Diseases That Threaten Chrysanthemum Production

Two diseases in particular plague commercial chrysanthemum growers worldwide. White rust, caused by the fungus Puccinia horiana, produces disfiguring white pustules on the undersides of leaves and is a quarantine-regulated pathogen in many countries. Resistance varies dramatically among chrysanthemum species: screening of wild chrysanthemum accessions found that species like C. boreale and C. zawadskii were completely resistant, showing no infection at all, while C. indicum was highly susceptible, developing chlorotic lesions and pustules rapidly.¹² These resistant wild species are valuable breeding resources for introducing rust resistance into commercial cultivars.

Chrysanthemum stunt viroid (CSVd) is another major threat. This tiny infectious agent, even smaller than a virus, stunts growth, reduces flower size, and can devastate an entire crop. It spreads easily through mechanical contact during pruning and handling. Some chrysanthemum germplasms show natural resistance to CSVd, and identifying and breeding from these resistant lines is an active area of research.¹³ Because viroids cannot be treated with pesticides, resistance breeding and strict sanitation protocols are the main lines of defense.

Surviving Drought and Other Stresses

As climate conditions become more variable, understanding how chrysanthemums handle abiotic stress has become increasingly important. Chrysanthemum is moderately drought-sensitive, and dehydration triggers sweeping changes in gene expression. Profiling studies have identified thousands of drought-responsive genes, with changes concentrated in hormone signaling, secondary metabolism, and antioxidant defense pathways.¹⁴

One promising approach to improving drought tolerance is the application of melatonin, a hormone better known for regulating sleep in humans but also produced naturally by plants. When applied externally to chrysanthemum under drought conditions, melatonin increased photosynthetic capacity substantially, boosted antioxidant enzyme activity by roughly 20 to 35 percent depending on the enzyme, and raised the plants’ soluble sugar levels by over 40 percent, all of which help the plant maintain function under water stress.¹⁵ The treatment also reshaped the plant’s internal hormone balance, increasing growth-promoting hormones and decreasing stress hormones like abscisic acid. While this is not yet a standard commercial practice, it points toward chemical treatments that could help chrysanthemum production in drought-prone regions.

Tissue Culture and Clonal Propagation

Because of its hexaploid genetics and hybrid origin, chrysanthemum does not breed true from seed. Commercial propagation relies overwhelmingly on vegetative methods, primarily stem cuttings. But biotechnological approaches offer additional options. Researchers demonstrated somatic embryogenesis, the formation of embryo-like structures from non-reproductive tissue, using ray-floret explants (tiny pieces of the flower’s petal-like structures) from Dendranthema grandiflorum. By culturing these on media containing specific plant hormones, they generated embryos that developed into complete plants.¹⁶ This technique is useful for producing virus-free stock, for genetic transformation experiments, and for rapidly multiplying elite cultivars.

Drying Chrysanthemum Flowers for Tea

Chrysanthemum tea is one of the most popular herbal beverages in East Asia, and the drying method used to prepare the flowers has a meaningful effect on what ends up in your cup. A study on Chrysanthemum morifolium found that a brief microwave treatment followed by hot-air drying at 75°C was the most effective method for preserving biologically active compounds, yielding flowers with higher antioxidant capacity and greater ability to inhibit acetylcholinesterase compared to other drying approaches.¹⁷ For a related species used in flower tea, hot-air drying at lower temperatures (around 30°C) struck the best balance between quality preservation and energy efficiency.¹⁸ The takeaway for anyone processing chrysanthemum flowers at home: gentle heat preserves more of the good stuff than aggressive high-temperature drying, and a short initial microwave burst can help lock in active compounds before slower drying begins.

An Unexpected Environmental Application

Wild chrysanthemum species, particularly Dendranthema indicum, have shown a surprising talent for accumulating heavy metals from contaminated soil. A survey of dominant plant species growing on a lead-zinc mining site in Nanjing found that D. indicum had a bio-transfer factor greater than one for six different heavy metals, meaning the plant concentrated metals in its above-ground tissues at levels exceeding those in the surrounding soil.¹⁹ This classifies it as a metal accumulator rather than an excluder, and it raises the possibility of using wild chrysanthemum in phytoremediation schemes, where plants are grown on contaminated land specifically to draw pollutants out of the soil. The plants are then harvested and disposed of, gradually cleaning the site. It is a slow process, but for large areas of low-level contamination where excavation is impractical, accumulator plants like D. indicum offer a low-cost, low-energy alternative. The same trait that makes the plant useful for remediation is worth keeping in mind if you are foraging wild chrysanthemum near industrial areas or old mining sites: the flowers may carry elevated metal levels that make them unsuitable for tea or medicinal use.