Drosera Linnaeus (1753: 281)

Gonella, Paulo Minatel, Sano, Paulo Takeo, Rivadavia, Fernando & Fleischmann, Andreas, 2022, A synopsis of the genus Drosera (Droseraceae) in Brazil, Phytotaxa 553 (1), pp. 1-76 : 16

Drosera Linnaeus (1753: 281) .

Type: Drosera rotundifolia Linnaeus (1753: 281) .

Characters only given for taxa occurring in South America (Table 2), hence some generic character states (like regular tetramery or polymery of flowers; tubers; gemmae) are not mentioned here. For a global generic circumscription see Fleischmann et al. (2018a).

Carnivorous herbs, terrestrial or rupicolous, perennial (including seasonal geophytes and hemicryptophytes) or rarely annual. Roots capilliform to succulent, pale brown to black, scarcely branching, sparsely to densely covered by root hairs. Stem either (1) much condensed, with leaves restricted to a flat rosette (acaulescent or rosulate species; this habit corresponds to Diels 1906: 32, fig. 13B), (2) forming short stems densely covered by marcescent leaves (columns; this habit corresponds to Diels 1906: 32, fig. 13E; distinction between (1) and (2) not always clear, often depending on habitat and age of the plant), or (3) plants caulescent, internodes well-developed, forming erect or prostrate stems, rarely branching (stem-forming species; this habit corresponds to Diels 1906: 32, fig. 13C). Leaves simple, spirally arranged, rosulate or along distinct internodes, petiolate or rarely sessile, persistent on the stem, green, yellow-orange, red to vinaceous; lamina spatulate, obovate, oblong, lanceolate, or linear in shape (including variations), densely covered by carnivorous glandular emergences (tentacles) on the adaxial surface, glabrous or glandular- and/or eglandular-pilose on both surfaces, tentacles uniform or dimorphic with unifacial marginal glands (“snap-tentacles”) present on the apical margin of the leaves; petiole (if present) linear to (narrowly) cuneate, indumentum usually similar to the noncarnivorous indumentum of the lamina; leaf vernation circinate, circinate-involute, geniculate, geniculate-involute, or entire-involute (see Figs. 2, 3; also see Diels 1906: 16, fig. 5); stipules intrapetiolar, translucent-golden-brown, red or white (often brown in dried specimens), membranaceous, triangular to rectangular, margins entire, laciniate or strongly fimbriate, or reduced to two lateral setae adnate to the petiole base ( D. brevifolia ), or absent [ D. uniflora Willdenow (1809: 340) ]. Inflorescence a scorpioid-cyme (simple or branched), multiple-, few- or single-flowered; peduncle lateral or terminal, terete, usually very long, flowers rarely (sub-)sessile [ D. amazonica Rivadavia, Fleischmann & Vicentini in Rivadavia et al. (2009: 13)], scape glandular- and/or eglandular-pilose or glabrous; bracts filiform to subulate, caducous, often absent in mature inflorescences; pedicels glandular- and/or eglandular-pilose, or glabrous, erect in flower and fruit, rarely reflexed in fruit ( D. amazonica ). Flowers actinomorphic, bisexual, tetracyclic. Calyx 5-merous, sepals united at the base at different degrees, oblong, ovate, lanceolate, obovate or suborbicular, glandular- and/or eglandular-pilose on the abaxial surface, or glabrous, adaxial surface always glabrous, persistent. Corolla 5-merous, petals free, obovate, pink to white in color, persistent. Androecium 5-staminate, stamens free; anthers extrorse, bithecate, tetrasporangiate, with longitudinal dehiscence; pollen released in tetrads, orange to yellow, rarely white. Gynoecium 3- or 5-merous, syncarpous, ovary superior, unilocular, with parietal placentation and numerous ovules; styles 3, with style-arms forked at the base, or styles 5, and entire; stigma simple, bilobate, spatulate, flabellate or multiplebranched. Fruit a dehiscent dry capsule, 3- or 5-valvate, globose or ellipsoid or cup-shaped [in D. kaieteurensis , D. felix Steyermark & Smith (1974: 491) , D. solaris ]. Seeds numerous, brown to black, ovoid, oblong, ellipsoid, fusiform or rectangular, testa reticulated, foveolate or papillose.