All species › Caryophyllales › Sundew family › Drosera gibsonii
Drosera gibsonii
A pygmy sundew that, as far as known, grows in a single place in the world: Stirling Range National Park, the mountain range that rises like an island from the plain north of Albany. Paul Mann described Drosera gibsonii in 2007 in Nuytsia and named it after the Australian sundew specialist Robert Gibson. It is a late bloomer with pink to mauve flowers, growing on lateritic gravel in open heath.
Identification
A perennial, fibrous-rooted pygmy sundew with a semi-erect rosette no more than 1.25 cm across, on a stem up to 4 cm tall covered in the withered remains of earlier seasons. The rosette has 6 to 12 leaves with a narrowly elliptic blade 3 by 1.5 mm on a 5 mm petiole. The stipules are 6.5 mm long and three-lobed, the central lobe divided into four segments. The scape reaches no more than 3 cm and bears 7 to 12 pink to mauve flowers; the petals measure 8 by 5 mm. The styles are mauve, 3.5 mm long, with translucent white, club-shaped stigmas; the pollen is yellow. The gemmae measure 1.5 by 1.2 by 0.75 mm.
Similar species
The closest relative is Drosera silvicola (treated by some as a subspecies of D. barbigera). D. gibsonii differs in its shorter scape (to 3 cm against 8 cm or more), fewer flowers (7 to 12 against up to 20), mauve rather than red styles and yellow rather than white pollen. Other pygmy sundews in the Stirling Range are told by flower colour, stipules and stem.
The trap and how it works
An active flypaper trap. The tiny, narrowly elliptic blades 3 mm long bear stalked glands with droplets of glue in which springtails, mites and minute flies are caught. The tentacles bend towards the prey and secrete digestive enzymes. On poor lateritic gravel this by-catch matters for the plant's nitrogen and phosphorus budget.
Habitat and ecology
Lateritic gravel among Allocasuarina shrubs in open heath on mountain slopes, at about 400 m altitude (Mann 2007; FloraBase) (D3, B5). The higher elevation gives a cooler and moister climate than the surrounding plain, which explains the late flowering in November and December.
Distribution and elevation
Endemic to the south-west of Western Australia, as far as known confined to one area in Stirling Range National Park (Esperance Plains, Fitzgerald subregion). The exact locality was deliberately withheld in the original description, and this guide follows that example.
- Recorded (one-degree cells)
Forms and variation
No subspecies or varieties have been described. Like all pygmy sundews the species also reproduces by gemmae, which were measured in the original description. Confined to one site, its genetic variation is probably small.
Where and when to see it
Stirling Range National Park is one of the richest plant areas in Australia in spring. Keep strictly to the paths there: park management applies measures against the spread of the root rot Phytophthora cinnamomi, which affects large parts of the heath, and a species with a single site cannot tolerate trampling. Late bloomers such as this one are seen in November and December.
Conservation status
The IUCN code in this guide is Vulnerable (VU); in Western Australia the species is listed as Priority Two. Not in CITES. A single known site makes the species sensitive to any disturbance: too-frequent fires, Phytophthora root rot affecting the associated shrubs, and trampling.
Scientific name
Drosera gibsonii | Mann, 2007
Described by P. Mann in 2007, in "Drosera gibsonii (Droseraceae), a new Pygmy Drosera from south-west Western Australia", Nuytsia, volume 16, no. 2, p. 321-323. Stirling Range National Park, Western Australia — the only known population/location of this species. Named after a person surnamed Gibson, but exactly who is being honoured could not be established.
World Checklist of Vascular Plants (WCVP), via Plants of the World Online (POWO), Royal Botanic Gardens, Kew.