Drosera zigzagia — Vorstman's Guide to the Carnivorous Plants

Identification

An erect perennial tuberous plant 5 to 7 cm tall, with a zigzag stem along which the small trapping leaves stand singly and alternately — the stem bends at each leaf. The inflorescence carries four to nine yellow flowers, which appear in August and September. Exact leaf and flower measurements are not published in the sources consulted.

Similar species

Drosera salina grows on the same salt-lake margins, also small and erect, but with white flowers and without the clear zigzag stem. Other yellow-flowered tuberous sundews such as D. subhirtella and D. sulphurea are climbers tens of centimetres long and do not grow by salt lakes.

The trap and how it works

An active flypaper trap, but held well above the ground. The leaves along the stem are small, peltate and often cup-shaped, with longer tentacles on the margin and shorter ones on the blade. Flying insects — midges, small flies, sometimes bees or butterflies drawn to the flowers — touch the droplets and stay hanging. The marginal tentacles then bend inwards and the blade partly closes around the prey, after which the glands secrete enzymes and absorb the dissolved nutrients. Because the traps are spread along an upright or climbing stem, the plant sweeps a much larger volume of air than a rosette on the ground.

Habitat and ecology

The margins of salt lakes, on brown sandy loam (D4, D1). There the plant often grows together with Drosera salina, Stylidium species, Levenhookia leptantha and Frankenia — a characteristic assemblage of the sandy transition zone around salt lakes.

Distribution and elevation

Endemic to Western Australia, in the south, around salt lakes. No closer delimitation is given in the sources consulted. Altitudinal limits are not published.

Recorded (one-degree cells)

Distribution based solely on records at GBIF (Global Biodiversity Information Facility), not on TDWG regions — those are often far larger than the actual range. The light halo is the area around a record, the dark core the record itself. The darker cells are 11 one-degree squares — roughly a hundred and ten kilometres — in which the species has been recorded, from all GBIF records. This is coarser than for most species because hardly any record of this plant carries an accurate coordinate: the locality of poached species is obscured at source. At this scale that obscuring disappears into the noise. The cells show where it has been seen, not where it occurs: an empty square means nothing.

Forms and variation

Allen Lowrie described the species in 1999 and placed it in subgenus Ergaleium, section Ergaleium. A synonym is Drosera huegelii var. flaviflora W.Fitzg. ex Ewart, an older name that already pointed to the yellow flowers. No subspecies are recognised.

Where and when to see it

August and September, in sunshine, when the yellow flowers are open. Search the sandy, slightly raised margin of salt lakes, and look for small plants with a kinked stem among Frankenia and Stylidium. Keep off the salt crust — it is soft after rain and trampling leaves long-lasting marks.

Conservation status

Assessed as Least Concern (LC) on the IUCN Red List; not listed in CITES. The sources consulted name no specific threats. Salt-lake margins in the wheatbelt are, however, affected by the salinisation that follows clearing.

Scientific name

Drosera zigzagia | Lowrie, 1999

Drosera zigzagia was described in 1999 by Allen Lowrie, published in Nuytsia, volume 13(1), page 85 (within the article spanning pages 75–87). The species is endemic to Western Australia and occurs on the margins of salt lakes in brown sandy loam; a precise type locality with collector and collection date could not be established with certainty. The name zigzagia is a descriptive term, derived from the word "zigzag", and refers to the small, solitary carnivorous leaves that alternate along a zigzagging stem — a distinctive morphological feature of this species.

World Checklist of Vascular Plants (WCVP), via Plants of the World Online (POWO), Royal Botanic Gardens, Kew.