Published In:
Nova Genera Plantarum 2(34):. 1782. ([10 Jul 1782]) ( Nov. Gen. Pl.)  
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(Last Modified On 6/6/2016)
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Acceptance
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Accepted
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(Last Modified On 6/6/2016)
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Description:
Plants 1–3 m high, ± erect or sprawling in dense vegetation. Stem upright or inclined, simple or with a few branches, leafy part 3–5 mm wide, 10–15 mm diam. near base. Leaves narrowly lanceolate, 100–150 × 4–7 mm, dark green. Inflorescence with 8–16 flowers (4–8 flower pairs), each pair subtended by 3–5 acute bracts at base of each binate rhipidium, each with stalks 2–4 mm long; spathes 35–40 mm long, emarginate, sheathing lower half of tube, floral bracts 2-keeled, 15–18 mm long, concealed by spathes. Flowers pale green below, dark green above shading to blackish at top of tube, tepals blackish in lower half, outer tepals densely villous and yellow in upper half, inner mostly concealed by outer, pale green, yellow and villous at tips where exposed; perianth tube 50–55 mm long, ± 3 mm wide at base, wider above bracts, 6 mm wide at apex, lower half usually filled with nectar; tepals lanceolate, ± erect, closed over stamens, 25–30 mm long, limbs 10–12 mm long, outer tepal limbs velvety-pubescent outside, inner tepals covered by outer except at apex, inner tepals pubescent at tips. Filaments ± 10 mm long; anthers oblong-linear, 5–6 mm long, appressed to inner surface of outer tepals, yellow; pollen yellow. Style extending 2–3 mm from tepals when receptive, later retracting, minutely 3-forked. Capsules narrowly obovoid, 9–12 mm long. Seeds 6–7 mm long, 1 per locule. Flowering time: mainly late spring and summer, October to December but also at other times.
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South African Province:
Western Cape
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Distribution and ecology:
endemic to southern Western Cape, extending from the southern Cape Peninsula through the Caledon district to at least the eastern end of the Riviersonderend Mtns and possible the Langeberg at Swellendam; at low to middle elevations in marshy or peaty ground.
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Diagnosis:
the shrubby evergreen habit and apically clustered fan leaves of Witsenia maura indicate a close relationship with Klattia and Nivenia, the two other genera of shrubby Iridaceae. However, the structure of the inflorescence and the flower is so different from that in these two genera that it is difficult to accurately assess their interrelationships. The inflorescence is a false panicle with short lateral branches each of which bears a pair of flowers arranged in a binate rhipidium, a pattern similar in basic organization to that in some species of Nivenia. This is the putatively primitive organization for the woody Iridaceae and recalls the condition in some species of Aristea. Thus the inflorescence structure of Witsenia is probably fairly primitive, although the enlarged, leathery, emarginate spathes and bracts are unlike anything found in the other shrubby genera. Despite their obvious differences, similarities in the flowers of Klattia and Witsenia suggest the two genera are more closely related to one another than to Nivenia. The similarities include presence of clawed tepals, flattened filaments inserted in a pouch at the bases of the anthers and minutely trifid styles. Klattia is, however, very different from Witsenia in its crowded, head-like inflorescences, linear spathulate tepals, short perianth tube and enlarged leaves enclosing the inflorescences. The velvet pubescence on the tepals of Witsenia is unusual in Iridaceae. It is produced by densely arranged multicellular hairs containing yellow chromoplasts.
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General Notes:
First species of the woody Iridaceae known to science, Witsenia maura was described by Carl Linnaeus in 1771, initally as Witsena, the spelling later altered to Witsonia. The species was first known in 1790 in Britain from the herbarium collections of Francis Masson. Seed collected by James Niven, who visited the Cape in the years 1798–1803 and 1803–1810, was raised at Lee and Kennedy's nursery at Hammersmith, London, and first flowered there in 1814 and the illustration made at that time was published in the Botanical Register. Although its striking appearance made it a desirable hothouse subject, it was not widely grown and difficult to maintain for extended periods. Nevertheless, W. maura had persisted in cultivation at least until 1841 and the fine plate published in Paxton's Magazine of Botany in that year was drawn from a living specimen. It has proven difficult to maintain today at Kirstenbosch Botanic Gardens in Cape Town, even though planted in apparently the same type of soil and in the marshy conditions in which it grows in the wild.
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Pollination:
Flowers of Witsenia maura are adapted for pollination by sunbirds. The firmly closed tepals would appear to prevent insects entering the flowers, thus limiting their access to both pollen and the nectar-filled lower perianth tube. Only the malachite sunbird seems strong enough to part the tepals with their beaks and this is the only pollinator so far noted visiting the flowers, which contain large quantities of sugary nectar of relatively low concentration.
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