Dionaea muscipula

Morphology

Flora of North America Editorial Committee (eds.). Flora of North America North of Mexico, vol. 6 — Droseraceae, Dionaea Solander ex J. Ellis, Flora of North America Association / eFloras.org · www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=110284 · 2026-09-10

Dionaea comprises perennial, evergreen plants. The scapes arise from bulblike rhizomes encased in fleshy petiole bases; the leaves persist and do not form overwintering buds (hibernaculae). The roots are adventitious, white and unbranched.

The leaves lack stipules and the petiole is winged. The blade — greenish or bright red adaxially — consists of two subreniform lobes hinged along the midrib, with margins bearing stout bristles; each lobe carries three trigger hairs on its adaxial surface, and proper stimulation of these hairs makes the lobes snap shut on prey.

Inflorescences are umbel-like cymes. The flowers have marcescent white petals, (10–)15(–20) distinct stamens, a 5-carpellate gynoecium, a single undivided style and a plumose stigma. The fruit is an ovoid capsule opening irregularly, with (20–)25(–30) seeds. The base chromosome number is x = 16. The genus holds a single species, from the United States, introduced elsewhere.

Phenology and habitat

Flora of North America Editorial Committee (eds.). Flora of North America North of Mexico, vol. 6 — Dionaea muscipula J. Ellis, Flora of North America Association / eFloras.org · www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=220004158 · 2026-09-10

Flowering runs from late May to June. The species grows in moist sandy-peaty soil and sphagnum mats of roadsides, ditch banks, borrow-pits and longleaf pine savannas, from 0 to 100 m in elevation.

It is very sensitive to shading and drought, and may go dormant during dry periods or if its habitat does not burn every five years or so. It occupies sites with saturated but not inundated soils under strong sunlight — especially ecotones between pocosins and longleaf pine-dominated savannas or sandhills.

In southeastern North Carolina and adjacent South Carolina it grows in association with no fewer than 16 other species of carnivorous plants, the highest diversity of carnivorous plants anywhere in the world.

Distribution and the shrinking native range

Flora of North America Editorial Committee (eds.). Flora of North America North of Mexico, vol. 6 — Dionaea muscipula J. Ellis, Flora of North America Association / eFloras.org · www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=220004158 · 2026-09-10

The species historically occurred in the outer Coastal Plain, from Beaufort County, North Carolina, to Charleston County, South Carolina, and inland as far as Moore County, North Carolina. Its present native range is much reduced by drainage, habitat conversion, fire exclusion and development.

It has been introduced into southern Alabama, northern California, eastern Pennsylvania and Caroline County, Virginia, where it is doubtfully truly naturalized; it is reportedly naturalized in the Apalachicola region of Florida, southern New Jersey and Skagit County, Washington.

How the trap works

Flora of North America Editorial Committee (eds.). Flora of North America North of Mexico, vol. 6 — Dionaea muscipula J. Ellis, Flora of North America Association / eFloras.org · www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=220004158 · 2026-09-10

The trigger hairs must be touched twice in close succession for the trap to snap shut, which takes less than a second; the marginal bristles help keep active prey from escaping. Requiring a double stimulus prevents inorganic debris and casual raindrops from closing the trap.

When lightly closed, the two lobes come together and appear convex, opening again the next day if nothing was caught. If a protein meal is detected, the lobes tighten completely, become slightly concave, squeeze the victim and secrete digestive enzymes. Once the prey is digested, the trap grows itself open again, exposes the indigestible carcass and remains viable for some time. New leaf-traps form constantly, curling open in a somewhat circinate fashion, as old ones die and turn black.

How many stimuli the plant counts

Böhm, Scherzer, Krol, Kreuzer, von Meyer, Lorey, Mueller, Shabala, Monte, Solano, Al-Rasheid, Rennenberg, Shabala, Neher & Hedrich (2016). The Venus flytrap Dionaea muscipula counts prey-induced action potentials to induce sodium uptake. Current Biology 26(3): 286–295, Cell Press · doi.org/10.1016/j.cub.2015.11.057 · 2026-09-10

Böhm and co-workers measured how many stimuli each step requires. Touching the mechanosensors on the inner surface fires action potentials, and two of them are enough for the trap to snap shut on the prey. The jasmonic acid signalling pathway is activated after the second stimulus; expression of the genes encoding the prey-degrading hydrolases, in turn, requires more than three action potentials and is proportional to the number of mechanical stimulations.

The authors also identified the sodium channel DmHKT1 as responsible for the uptake, through the glands, of the sodium load carried by the decomposing animal — with transcript numbers likewise depending on the number of mechano-electric stimulations. Their conclusion is that the number of action potentials a victim triggers while trying to break out is what identifies the captured object as a sodium-rich animal rather than debris.

Digestion and absorption

Freund, Graus, Fleischmann, Gilbert, Lin, Renner, Stigloher, Albert, Hedrich & Fukushima (2022). The digestive systems of carnivorous plants. Plant Physiology 190(1): 44–59, Oxford University Press / American Society of Plant Biologists · doi.org/10.1093/plphys/kiac232 · 2026-09-10

The trap is a leaf bearing specialised glands that secrete mucilage, fluid, acids and proteins, digestive enzymes among them, and then absorb the released compounds through membrane transport proteins or endocytosis. Prey does not travel through a digestive tract: it stays in the same organ where it was captured while digestion and absorption take place.

The digestive fluid of carnivorous plants often reaches pH 2–3, on average more acidic than the gastric acid of insect-eating animals, and that acidity is generated mainly by hydrochloric acid. Alongside proteases, the enzymatic repertoire includes chitinases, which break down the chitin of the arthropod exoskeleton, as well as ribonucleases, amylases, esterases and phosphatases.

In Dionaea, the ammonium transporter AMT1 shows gland-specific expression (Scherzer et al., 2013, cited in the review), and cuticular permeability appears only in mature glands — immature ones do not stain in dye assays (Adlassnig et al., 2012, cited in the review).

Genome and the evolution of carnivory

Palfalvi, Hackl, Terhoeven, Shibata, Nishiyama, Ankenbrand, Becker, Förster, Freund, Iosip, Kreuzer, Saul, Kamida, Wanke, Rensing, Kuwabara, Hasebe, Hedrich & Fukushima (2020). Genomes of the Venus flytrap and close relatives unveil the roots of plant carnivory. Current Biology 30(12): 2312–2320.e5, Cell Press · doi.org/10.1016/j.cub.2020.04.051 · 2026-09-10

The genome of Dionaea muscipula measures 3.18 Gbp — comparable in size to the human genome —, a figure obtained by flow cytometry both in cultured lines and in plants collected from a native North Carolina population. For comparison, the same authors obtained 509 Mbp for Aldrovanda vesiculosa and 323 Mbp for Drosera spatulata.

Comparing the three genomes pointed to an early whole-genome duplication in the Droseraceae as the source of carnivory-associated genes, and showed that recruiting genes from the root to the trap was a central mechanism in the evolution of the carnivorous habit. Even so, these genomes are among the gene-poorest sequenced in land plants so far: the evolution of carnivory came with massive gene loss.

Variation in petiole and trap colour

Flora of North America Editorial Committee (eds.). Flora of North America North of Mexico, vol. 6 — Dionaea muscipula J. Ellis, Flora of North America Association / eFloras.org · www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=220004158 · 2026-09-10

Leaf petioles vary from relatively long to short, apparently under genetic as well as environmental influences, and the adaxial surface of the traps may be bright red or greenish. Strong sunlight sometimes brings out the red colour, but not always. Variants in which the whole plant is a rich red-burgundy have been found in cultivation, and there are cultivars differing in the length of the marginal bristles.

Placement in the family

Flora of North America Editorial Committee (eds.). Flora of North America North of Mexico, vol. 6 — Droseraceae, Dionaea Solander ex J. Ellis, Flora of North America Association / eFloras.org · www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=110284 · 2026-09-10

Dionaea has been placed in its own family, Dionaeaceae Rafinesque — a treatment not without merit, as virtually all of its diagnostic features differ from those of Drosera. Molecular analysis, however, places the genus in the Droseraceae in the narrow sense (Cameron et al., 2002; Williams et al., 1994; Rivadavia et al., 2003, cited in the Flora of North America).

Nomenclatural history

International Plant Names Index — Dionaea muscipula J.Ellis, 1768, International Plant Names Index · www.ipni.org/n/urn:lsid:ipni.org:names:275898-2 · 2026-09-10

Dionaea muscipula J.Ellis was published in a London daily newspaper: the St James's Chronicle; or, the British Evening-Post, no. 1172, page [4], in the issue of 1–3 September 1768. IPNI records the name as tax. nov. and notes that lectotypification rests on a published illustration, with the information given in the Botanical Journal of the Linnean Society 99: 253 (1989).

The genus, in the same issue of the newspaper

International Plant Names Index — Dionaea Sol. ex J.Ellis, St. James's Chronicle; or, the British Evening-Post 1172: [4] (1768), International Plant Names Index · www.ipni.org/n/30217762-2 · 2026-09-10

The genus was published in the same place and on the same date, as Dionaea Sol. ex J.Ellis — St James's Chronicle; or, the British Evening-Post no. 1172, page [4], early September 1768.

The name in Linnaeus, 1771

International Plant Names Index — Dionaea muscipula J.Ellis ex L., Mant. Pl. Altera: 238 (1771), International Plant Names Index · www.ipni.org/n/321763-1 · 2026-09-10

Linnaeus used Ellis's name in Mantissa Plantarum Altera, page 238, in October 1771. IPNI records that entry as Dionaea muscipula J.Ellis ex L. and notes that Linnaeus used there the name published by Ellis in 1768.

The 1773 republication

International Plant Names Index — Dionaea J.Ellis, Nova Acta Regiae Soc. Sci. Upsal. 1: 98, t. 8 (1773), International Plant Names Index · www.ipni.org/n/14418-1 · 2026-09-10

In 1773, Nova Acta Regiae Societatis Scientiarum Upsaliensis 1: 98, t. 8, carries the genus again, as Dionaea J.Ellis. IPNI notes that Linnaeus, the author of the article, referred the genus name to Ellis's 1768 publication. It is this 1773 publication that POWO records in the nomenclatural history of the species, in the structured data above.