Drosera anglica |
Droseraceae |
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droséra d'angleterre, English sundew, giant sundew, great sundew, line-leaf sundew, long leaf sundew |
sundew family |
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Habit | Plants forming winter hibernaculae, rosettes 2–6 cm diam.; stem base not bulbous-cormose. | Herbs, annual or perennial, carnivorous, scapose. |
Leaves | erect; stipules entirely adnate to petioles, 5 mm, margins fimbriate along distal 1/2; petiole differentiated from blade, 3–7 cm, glabrous or sparsely glandular-hairy; blade obovate to elongate-spatulate, 1.5–3.5(–5) cm × 3–7 mm. |
in basal rosettes (alternate-cauline in Drosera intermedia); stipulate or estipulate; petiolate; blade infolded or circinate in vernation, modified as hinged, jawlike trap (Dionaea) [Aldrovanda] or bearing mucilage-tipped, irritable, multicelled hairs (Drosera) [Drosophyllum]. |
Inflorescences | 1–12-flowered; scapes 3–25 cm, glabrous. |
terminal, umbel-like cymes (Dionaea) or lateral, circinate or scorpioid cymes (Drosera), multiflowered (rarely 1-flowered). |
Flowers | 8–10 mm diam.; sepals connate basally, oblong, 5–6 × 4–5 mm, minutely glandular-denticulate; petals usually white, rarely pinkish, spatulate, 5–6 × 2–3.5 mm. |
perianth and androecium hypogynous; sepals 5, distinct or connate basally; petals 5, distinct; stamens usually 5 (Drosera) or (10–)15(–20) (Dionaea), distinct or sometimes connate basally; pistils 1, compound, 3–5-carpellate; ovary superior, 1-locular; placentation basal (Dionaea) or parietal (Drosera); styles 1 and undivided (Dionaea) or 3[5] and bifid (Drosera); stigma plumose (Dionaea) or capitate (Drosera). |
Fruits | capsular. |
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Capsules | 4–6 mm, minutely tuberculose. |
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Seeds | black, sigmoid-fusiform, 1–1.5 mm, length 1–2 times width, longitudinally striate-areolate. |
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2n | = 40. |
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Drosera anglica |
Droseraceae |
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Phenology | Flowering Jun–Aug. | |
Habitat | Marly shores, fens, drainage tracks in peat bogs | |
Elevation | 10–2600 m (0–8500 ft) | |
Distribution |
AK; CA; CO; ID; ME; MI; MN; MT; OR; WA; WI; WY; HI; AB; BC; MB; NB; NL; NT; ON; QC; SK; YT; Eurasia
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Nearly worldwide |
Discussion | Drosera anglica is a boreal species that occurs on calcareous substrates. It often grows with D. rotundifolia in peat bogs, and with D. linearis and D. rotundifolia in marl fens, especially in the Great Lakes region. C. E. Wood Jr. (1955) presented a strong case for the hybrid origin of D. anglica, suggesting that it arose as a fertile amphiploid hybrid between D. rotundifolia and D. linearis. It is the only tetraploid North American species of Drosera with 2n = 40. The sterile hybrid D. rotundifolia × D. linearis may be found whenever these species grow together. To avoid confusion, and because a formal name for the sterile hybrid has not been published, it should not be called Drosera ×anglica Hudson, as is commonly done. According to D. E. Schnell (2002), the fertile species may be distinguished from the sterile hybrid by its wider flowers (8–10 mm versus 6–7 mm) and wider scapes (1.5–2 mm versus 1–1.2 mm). The hybrid between Drosera rotundifolia and D. anglica is a sterile triploid, and has been formally named Drosera ×obovata Mertens & W. D. J. Koch. Because Drosera longifolia Linnaeus cannot be convincingly typified and has been so often used for plants of D. anglica and D. intermedia in the literature (F. E. Wynne 1944), the name D. longifolia has been rejected as ambiguous. Drosera anglica is found in the Aalakai Swamp at 1500–2000 meters on the Hawaiian island of Kauai (perhaps brought by migrating birds from Alaska); it is otherwise found in cold northern climates. D. E. Schnell (2002), who has grown the Kauai plants from seed, postulated that the high elevation provides a cooler temperature, and noted that plants from there do not form winter hibernaculae but only smaller winter rosettes. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Genera 4, species ca. 175 (2 genera, 9 species in the flora). Droseraceae comprise carnivorous plants with an unusual, worldwide distribution. They live mostly in sunny, low-nutrient, moist-to-wet acidic sands, clays, seeps, and peat bogs, often subjected to periodic fires. They catch rather small prey in jawlike traps (Aldrovanda Linnaeus and Dionaea) or on sticky glandular hairs (Drosera and Drosophyllum Link). All genera, except Drosera, are monotypic and sometimes have been placed in separate families for various reasons. F. Rivadavia et al. (2003) indicated that Droseraceae are monophyletic including these three genera but excluding Drosophyllum; K. M. Cameron et al. (2002) believed that the Old World Aldrovanda is more closely related to Dionaea, and both genera are relicts of a more widespread distribution based on fossil pollen records. Some species of Droseraceae are grown worldwide as ornamental bog garden or terrarium specimens and as such have been given formal or informal cultivar names. Species of Drosera have been artificially hybridized for horticultural purposes; in the wild the rare hybrids that do occur are normally sterile. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Key | ||
Source | FNA vol. 6, p. 422. | FNA vol. 6, p. 418. |
Parent taxa | Droseraceae > Drosera | |
Sibling taxa | ||
Subordinate taxa | ||
Name authority | Hudson: Fl. Angl. ed. 2, 1: 135. (1778) | Salisbury |
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