AT A GLANCE
- Common Name: Oblong-leaved Sundew
- Scientific Name: Drosera intermedia
- Category: Plants
- Subcategory: Carnivorous Plants
- Range: Disjunct amphi-Atlantic distribution: temperate and boreal western and central Europe, eastern North America, and parts of the Caribbean and northern South America
- Habitat Type: Sunny, saturated peat bogs, wet hollows, sandy ditch edges, quaking peat pool margins, and damp peat cuttings with fluctuating water levels
- IUCN Red List Status: Least Concern
- Lifespan: Perennial carnivorous herb
- Diet: Carnivorous/Autotrophic (photosynthetic, supplemented by capturing and digesting midges, mosquitoes, flying ants, and small dragonflies)
- Average Size/Weight: Rosette diameter 4 to 8 cm; leaf blade length 10 to 15 mm, width 4 to 6 mm; flowering scape 8 to 20 cm tall
- Key Defining Feature: Graceful semi-erect carnivorous sundew forming a loose rosette of spatulate, spoon-shaped leaves bristling with brilliant crimson glandular tentacles weeping glistening glue drops
Overview
The Oblong-leaved Sundew (Drosera intermedia), also celebrated as the Spoonleaf Sundew, is a radiant and tenacious carnivorous perennial herb with a remarkable amphi-Atlantic distribution across both Europe and North America. Inhabiting the wettest, sun-drenched hollows of acidic peat bogs, this miniature predator forms delicate rosettes of ascending, spoon-shaped leaves covered in hundreds of glistening ruby-red tentacles. In summer, it transforms bleak, nutrient-poor peat bogs into shimmering fields of sticky crimson traps that ensnare passing insects.
Biology and Physical Characteristics
Drosera intermedia is easily distinguished from its close relatives by its semi-erect habit: while the Round-leaved Sundew hugs the moss flatly, the Oblong-leaved Sundew produces leaves on long, slender petioles that curve gracefully upward and outward, forming a loose, cup-like rosette. Each leaf blade (lamina) is obovate to oblong-spatulate (broadly spoon-shaped), measuring 10 to 15 mm long and 4 to 6 mm wide. The upper leaf surface is blanketed in hundreds of bright crimson stalked glands that exude glistening beads of viscous, sugary mucilage. In July and August, a lateral, curving flowering scape arises from the side of the rosette, bearing three to eight small, pristine five-petaled white flowers.
Behavior and Ecology
Drosera intermedia specializes in the pioneer colonization of bare, exposed, saturated peat mud and shallow bog depressions that experience seasonal inundation. When an insect lands on a glistening leaf, it is immediately trapped by the sticky polysaccharide glue. As the prey struggles, sensory impulses trigger an electrical action potential that causes neighboring tentacles to bend inward over the victim within minutes, pressing it firmly against the leaf surface. The glands then secrete a potent cocktail of digestive enzymes (acid proteases, esterases, and phosphatases) that dissolve the soft tissues of the insect, allowing the plant to absorb vital nitrogen, phosphorus, and potassium to fuel its growth in nutrient-starved peat.
Conservation and Human Impact
The Oblong-leaved Sundew is classified as Least Concern on the IUCN Red List globally due to its vast geographic distribution across North America and Europe. However, in Western and Central Europe, it is red-listed as Endangered or Vulnerable in many countries (such as Germany and Switzerland) where large-scale industrial peat extraction, wetland drainage for agriculture, and atmospheric nitrogen deposition have eradicated over 80 percent of historic bog habitats.
Interesting Factoid
The Oblong-leaved Sundew is a bog pioneer that can actually survive growing completely underwater for weeks at a time during spring floods, floating its spoon-shaped leaves on the surface before capturing insects once water levels drop.