Plants perennial, evergreen; scapes from bulblike rhizomes encased in fleshy petiole bases; leaves persisting, not forming overwintering buds (hibernaculae). Roots adventitious, white, unbranched. Leaves: stipules absent; petiole winged; blade greenish or bright red adaxially, of 2 subreniform, hinged lobes, margins with stout bristles (hinged along midrib, adaxial surfaces with 3 trigger hairs causing lobes to snap shut on prey when properly stimulated). Inflorescences umbel-like cymes. Flowers: petals marcescent, white; stamens (10–)15(–20), distinct; gynoecium 5-carpellate; style 1, not divided; stigma plumose. Capsules ovoid, opening irregularly. Seeds (20–)25(–30). x = 16.

Distribution

United States, introduced elsewhere.

Discussion

Species 1.

Dionaea has been placed in its own family, Dionaeaceae Rafinesque. This is not without merit, as virtually all of its diagnostic features are different from those of Drosera. Molecular analysis places it in the Droseraceae in the narrow sense (K. M. Cameron et al. 2002; S. E. Williams et al. 1994; F. Rivadavia et al. 2003).

Selected References

Hodick, D. and A. Sievers. 1988. On the mechanism of trap closure of Venus flytrap (Dionaea muscipula Ellis). Planta 179: 32–42.

Roberts, P. R. and H. J. Oosting. 1958. Responses of Venus fly trap (Dionaea muscipula) to factors involved in its endemism. Ecol. Monogr. 28: 193–218.

Williams, S. E. and A. B. Bennett. 1982. Leaf closure in the Venus flytrap: An acid growth response. Science, ser. 2, 218: 1120–1122.

Lower Taxa

Dionaea muscipula