Drosera capensis L. 'Alba'

Where it comes from

Much less of South Africa than everyone says. Kew gives the native range as one region — southern Cape Province — with no synonyms and no infraspecific taxa.¹ Not “southern Africa”, not “Africa”: a coastal South African endemic, running roughly between Port Elizabeth and Cape Town.² SANBI rates it not threatened.³

It has travelled, though. Kew records it naturalised in California and New South Wales,¹ and New Zealand found it at two sites in Auckland in 2001 and put it on the 2020 National Pest Plant Accord — because a single flower scape can carry one to two thousand seeds.⁴ That is the second plant on this site banned in New Zealand, after the Port Jackson fig, for the same reason: it reproduces there without help.

Linnaeus published the name in Species Plantarum in 1753.¹⁵ Capensis is for the Cape.

Naming and description

‘Alba’ is a trade name. The registered name is Drosera ‘Albino’. The International Carnivorous Plant Society is the registration authority, appointed in 1998,⁶ and its register lists 42 Drosera cultivars. ‘Alba’ is not among them. Drosera ‘Albino’ is — registered on 10 November 1998, originators R. Borret and N. Farrow, given as a selection of D. capensis and distinguished by a complete lack of anthocyanins.⁷

There is no botanical forma either: an IPNI search for Drosera capensis returns exactly one record, the species itself.⁸ So “D. capensis f. alba”, which you see on labels, has no standing at any rank.

And ‘Alba’ could not be established as a cultivar name now even if someone tried. The white plant appeared spontaneously in European cultivation in the 1980s and has never been reported from the wild,² and the Cultivated Plant Code stopped allowing new Latin-form cultivar epithets in 1959⁹ — which is presumably why the 1998 registrants reached for a modern-language word instead.

What is actually different about it is the absence of one pigment class. The tentacles are green rather than red and the flowers are white rather than pink. Everything else — the narrow strap leaves, the dew, the wrap — is the species.

Fun facts

• The red tentacles everyone admires do not attract prey. They repel it. A 2014 study tested attraction and camouflage in three field experiments and found red served neither function; the data release puts it more bluntly still — prey were not attracted to green traps and were deterred from red ones.¹⁰¹¹ The work was on D. rotundifolia rather than this species, and nobody has measured the white form’s capture rate. But on the evidence there is, an anthocyanin-free sundew is not handicapped and may be very slightly ahead.
• The leaf wraps around prey within about three hours, and it is triggered chemically rather than by touch. In a 2013 experiment on this exact species, the blade bent within three hours of capture, jasmonate accumulated only in the bending segment, and jasmonate alone was enough to cause it. The control is the useful part: only living fruit flies or crushed body fluids produced the curl — dead flies and mechanical prodding did nothing.¹² Which is why the advice is to feed live or rehydrated food onto a dewy leaf.
• The dew is glue, not stomach acid. It is about two thirds very-high-molecular-weight polysaccharide, and its documented job is capture and retention rather than digestion.¹³ The enzymes — phosphatase, protease, chitinase — are a separate secretion, induced only once something is caught.¹⁴
• Feeding it measurably works, and feeding it the wrong thing measurably does not. Fed Cape sundews doubled their photosynthetic rate, biomass and leaf count in one experiment.¹⁵ But 93 per cent of the nitrogen in chitin went unabsorbed in another — so it is the soft parts of an insect that count, not the shell.¹⁶