Drosera arcturi, commonly known as the Alpine Sundew, is a perennial carnivorous plant species belonging to the genus Drosera (the sundews) in the family Droseraceae. It is native to subalpine and alpine regions of southeastern Australia (including Tasmania) and New Zealand, where it thrives in cold, wet, and nutrient-poor environments.
[[File:Drosera arcturi 02.jpg|thumb|Drosera arcturi in its natural habitat in Tasmania.]]
Description
Drosera arcturi typically forms a basal rosette of leaves, though it can develop an erect stem in certain conditions. The leaves are spatulate (spoon-shaped) to linear-spathulate, relatively large for a sundew, and often exhibit a reddish or greenish-red coloration, especially when exposed to strong sunlight. Like all sundews, the leaves are covered with glandular tentacles that produce a sticky mucilage, which traps and digests small insects. In colder climates, the plant forms a winter hibernaculum—a resting bud of tightly packed, non-carnivorous leaves—to survive freezing temperatures and snow cover.
Solitary white flowers, occasionally pinkish, are borne on an erect scape (flower stalk) that emerges from the center of the rosette. The flowers are generally small and consist of five petals. Individual plants can reach a diameter of 3-6 cm, with flower scapes extending up to 15 cm in height.
Distribution and Habitat
Drosera arcturi has a distinctive disjunct distribution across the cooler, high-altitude regions of the Southern Hemisphere:
- Australia: Found in Tasmania, Victoria (e.g., Bogong High Plains, Baw Baw Plateau), and New South Wales (e.g., Snowy Mountains).
- New Zealand: Present on both the North and South Islands, particularly in alpine and subalpine areas.
It is typically found in perpetually wet, highly acidic, and nutrient-poor soils. Its preferred habitats include:
- Subalpine and alpine bogs
- Wet moorlands
- Peaty soils
- Saturated moss beds This species is well-adapted to exposed, high-altitude environments, where it can tolerate harsh conditions, including frost and periods of snow cover.
Carnivory
As a carnivorous plant, Drosera arcturi supplements its nutrient intake by trapping and digesting insects. Its specialized leaves are equipped with stalked glands that secrete a sticky, glistening mucilage. When an insect lands on these glands, it becomes stuck. The plant then slowly curls its tentacles (and sometimes the entire leaf) around the prey, increasing contact with the digestive glands. Enzymes released from these glands break down the insect, and the absorbed nutrients, particularly nitrogen and phosphorus, compensate for the deficiencies in its boggy, peaty habitat.
Conservation Status
While not globally considered critically endangered, local populations of Drosera arcturi can be vulnerable to habitat degradation. Threats include changes in hydrology due to climate change, land management practices, and human disturbance in its specific high-altitude ecosystems. Its specialized habitat requirements make it sensitive to environmental shifts.
Etymology
The specific epithet "arcturi" was given by Sir Joseph Dalton Hooker in 1853. It is derived from Arcturus, a prominent star in the constellation Boötes. The precise reasoning for this naming choice in relation to the plant is not widely documented, but specific epithets often honor individuals, locations, or allude to characteristics or poetic associations.