(English sundew)
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Photo of Drosera anglica by Mary Beth Cook
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Drosera anglica (English sundew) is a small, bog-dwelling carnivorous plant. Plants are typically found rooted in Sphagnum (peat moss) mats. The leaves are all in a basal rosette, held upright. D. anglica has simple, paddle-shaped leaves at the end of long petioles (2-3 times the length of the blade) with entire margins.
The upper surface of the leaves is covered in long red hairs, each tipped with a transparent dot of mucous. This sticky substance serves to both attract and entrap insects. As an insect that lands on a Drosera leaf moves, it triggers a response in the leaf: other gland-tipped hairs bend toward it, further entangling the bug, and the leaf slowly curls around the insect and releases digestive enzymes to help break down the body, releasing nutrients for the plant.
English sundew is fully photosynthetic, and gains most of its energy (carbon) from the sun. However, in low-nutrient soils, capturing insects allows the plant to acquire limiting nutrients such as nitrogen and improve its growth.
The shape of the leaves (spatulate instead of round) and habit (leaves ascending, rather than flat on the ground) makes it easy to distinguish from the other local sundew, Drosera rotundifolia.
Often found without flowers, when fertile D. anglica will produce several flowers on a slender leafless stem above the basal rosette. Flowers have five white petals, up to 5 mm long, and five green sepals. The sepals have glandular hairs and the margins are entire or three-toothed. Inside the perfect flowers are yellow anthers, and three styles, each split in half to the base. Fruits are a many-seeded dehiscent capsule.
English sundew is a perennial species and flowers mid-summer.
Plants are
monoecious with bisexual flowers, though flowers are often absent. The species is most likely both self-fertile and insect pollinated. Although flowers do open, and are visited by insects, flowers only open in mid-morning and close in the afternoon, and insect visits are scarce. Additionally, flowers are small and lacking nectaries—not well-adapted to attracting insects. The pollen-to-ovule ratio for English sundew is 9 to 1—extremely low, and similar to plants that are obligately self-fertilizing (
Murza and Davis 2003). One observation of plants in Saskatchewan, Murza et al. found that different guilds of insects serve as prey and pollinators (
Murza et al. 2006). Whether and how much out-crossing occurs has yet to be determined. The seeds have air spaces in the outer coat, which may assist with floatation and dispersal.
Drosera anglica also reproduces vegetatively, and this is its predominant form of reproduction in a studied population in Japan (
Hoyo and Tsuyuzaki 2014).
This carnivorous plant may contribute nutrients to bogs (Matthews 1994). Plants are also collected by amateur botanists with an interest in carnivorous plants (seriously endangering some less common species), though this does not appear to be a concern in Alaska.
Disclaimer for Known Uses.
English sundew is a circumpolar, boreal-montane species that occurs across boreal North America. This species range extends southwards to the northern tier of U.S. lower 48 states, reaching as far south as California in the west and Michigan in the Midwest (it also occurs in Hawaii!). In Alaska, D. anglica occurs in peatlands across the lowland basins in mainland Alaska and along the southern coast, including Kodiak Island and numerous localities in the southeastern panhandle, but is apparently absent from the Aleutian chain and southern Alaska Peninsula. In Denali, it is not uncommon in large wetland complexes in the boreal zone on both sides of the Alaska Range.
Details are shown in the Plots & Charts found at right, depicting recent Denali data.
D. anglica is exclusively found in flat areas. It occurs from 74 to 689 m in the park, with the highest concentration of sites around 250 m.
Details are shown in the Plots & Charts found at right. For more on how to interpret these figures, visit Understanding Data Presented.
Like the more common roundleaf sundew, English sundew only grows in acid, boggy areas that are open and nutrient poor.
Poorly-drained wet to hydric sites.
