Droseraceae

Droseraceae R.A. Salisbury

Common name: Sundew Family.

Number of genera: 4 genera.

Number of species (Mabberley 1997): 85 species.

Disseminule type: Fruit (dehisced), or seed.

Division: Angiosperm.

Class: Magnoliopsida.

Fruits: Pistil(s) compound; 1; 1-pistillate; with carpels united. Fruit pericarpium; simple; capsule; loculicidal capsule; capsule not inflated; capsule without operculum; without persistent central column; not within accessory organ(s); more than 1 but less than 10-seeded to many-seeded; 3-seeded (to many); less than 1 cm long; 1.5 cm long (at least); with 3–5-carpellate; with carpels united; with carpels remaining united at maturity; without sterile carpels; in transection terete; apex not beaked; dehiscent. Dehiscent unit seed(s). Dehiscent without replum. Epicarp durable; glabrous; without armature; without wing(s); without apical respiratory hole. Mesocarp absent. Endocarp present; not separating from exocarp; thin; not splitting into 1-seeded pyrenes; smooth; without wing; without operculum; without secretory cavities; without mechanism for seedling escape; without grooves; without longitudinal ridges. Funiculus short; short without seed bearing hooks (retinacula); not persisting in fruit after seed shed.

Seeds: Aril absent. Seed minute, or larger than minute; less than 1 mm long, or 1 to less than 5 mm long; 0.8–1.5 mm long; fusiform, or straight, or ellipsoid; in transection terete; not bowl shaped; not nutlike; without winglike beak; without caudate appendage(s); at maturity with food reserves; with endosperm; without canavanine. Sarcotesta absent. Testa present; without markedly different marginal tissue; without fleshy or leathery layer over hard layer; loose, or tight; surface smooth, or unsmooth; surface with discreet raised features, or merged raised features; surface granular, or tuberculate, or papillate (& ending in reddish glands or not); surface ribbed, or reticulate, or striate, or ridged; without crease or line separating cotyledons from hypocotyl-radicle; without notch along margin where cotyledons from hypocotyl-radicle tip approach each other; without glands; without bristles; glabrous; without wings, or with wing(s); 2-winged; with wing at one end; with wing(s) solid; with solid wing(s) similar to testa; without collar; without operculum; colored; monochrome; brown (all shades), or black; crustaceous; not becoming mucilaginous when wetted, or becoming mucilaginous when wetted; surrounding food reserve. Hilum punctate. Endosperm development nuclear; copious; crystalline-granular; opaque; corrugated; with starch; with oils and proteins; without fatty acid containing cyclopropene; without apical lobes; without chlorophyll; without isodiametric faceted surface; without odor. Embryo differentiated from food reserve; well developed; 1 per seed; partially filling testa (with food reserve); chamber central to wings; 0.1–0.3 times the length of food reserve; at one end of seed not extending into a depression or cup; axile and centric and basal; conical, or miniature; dwarf; straight; parallel to seed length; with cotyledons gradually connected to hypocotyl-radicle; without coleorhiza; without simmondsin; without stomata; not green; with 2 or more cotyledons (barely developed). Cotyledons barely 2; tiny; 0.25 times length of embryo; as wide as hypocotyl-radicle; 1 times wider than hypocotyl-radicle; not concealing hypocotyl-radicle; not foliaceous; thin; smooth; with apices entire; with margins separate; basally entire; equal in size; not punctate dotted. Hypocotyl-radicle small; straight; not thickened.

General distribution: Cosmopolitan. New World and Old World.

Detailed distribution: North America to Oceania.

Notes: Steenis (1933) recorded loculicidal capsule for Aldrovanda, but Cronquist & Mabberley have indehiscent. Dionea seeds one-half embedded in placental tissue. Cotyledons truncate.

Noxious weeds: No USA noxious weeds listed for this family.

Familial synonyms:, Aldrovandaceae Nakai, Dionaeaceae Raf., Drosophyllaceae Chrtek et al., ,

Accepted Genera: Aldrovanda L., Dionaea Sol. ex J. Ellis, Drosera L., Drosophyllum Link

Literature specific to this family: Steenis, C.G.G.J. van. 1933. Contributions a l'Etude de la Flore des Indes Neerlandaises XXVII: Droseraceae. Bull. Jard. Bot. Buitenzorg, sér. 3, 13:106–109.

General references: Corner, E.J.H. 1976. The seeds of Dicots, esp. vol. 2. Cambridge University Press, New York, Cronquist, A. 1981. An integrated system of classification of flowering plants, 1,262 p. Columbia University Press, New York, Engler, A. & K. Prantl. 1924 and onward. Die Natürlichen Pflanzenfamilimien. W. Engelman, Leipzig, Gaertner, J. 1788–1805. De fructibus et seminibus plantarum. The Author, Stuttgart, Goldberg, A. 1986 (dicots) & 1989 (monocots). Classification, evolution, and phylogeny of the familes of Dicotyledons. Smithsonian Contr. Bot. 58 for dicots (314 pp.) & 71 for monocots (74 pp.). [Goldberg's illustrations are reproduced from older publications and these should be consulted], Gray, A. 1848. Genera florae Americae boreali-orientalis illustrata, 2 vols. James Munroe & Co., Boston., Gunn, C.R., J.H. Wiersema, C.A. Ritchie, & J.H. Kirkbride, Jr. 1992 & amendments. Families and genera of Spermatophytes recognized by the Agricultural Research Service. Techn. Bull. U.S.D.A. 1796:1–500, and Spjut, R.W. 1994. A systematic treatment of fruit types. Mem. New York Bot. Gard. 70:1–182.

Back to list of families

Suggested citation: Kirkbride, J.H., Jr., C.R. Gunn, and M.J. Dallwitz. 2006. Family Guide for Fruits and Seeds, vers. 1.0. URL: http://nt.ars-grin.gov/sbmlweb/OnlineResources/frsdfam/Index.cfm. Accessed November 20, 2009.

Systematic Mycology and Microbiology Laboratory
Questions about web site: HerbariumBPI@ars.usda.gov
Page last updated 22 May 2006

ARS Home | USDA.gov | Site Map | Policies and Links