Contributions Is Horokaka (Disphyma australe ssp. australe) more than a regional form of Disphyma crassifolium? by Eduart Zimer, Auckland, New Zealand There was and there still is a bit of confusion around the name Disphyma, a name full of surprises. The Genus Disphyma has a peculiar distribution to start with – from South Africa to Australia and New Zealand and further on to some South Pacific islands, with one of the populations from the Kermadec Islands seemingly the most isolated mesemb ever recorded, separated by 1,200 km of rough southern seas from the closest relative. This indicates an old gondwanic origin to me, but this is another story. Disphyma is a very interesting complex, even if in recent years was considered to be a monotypic genus, comprising only Disphyma crassifolium. Fig. 1 Disphyma australe, Bethels Beach Fig. 2 Disphyma australe, Bethels Beach The first description of a plant included in this complex Zealand native plant. was made by Linnaeus in 1753 - Mesembryanthemum Few years later, Haworth published a new name - crassifolium, a plant very common in South Africa (in Mesembryanthemum clavellatum (in Miscellanea Eastern Cape and Western Cape provinces). According naturalia, 1803). His description is based on plants to Alwin Berger [2] this plant was cultivated in Europe grown from seed collected by Robert Brown in Goose since 1727. Bay (south-western Australia). As a direct result at that time three different species have been erected, each of However, few decades later a similar plant was them assigned to the territories where the types have discovered in New Zealand. The first collection was made been discovered: in 1769 by Joseph Banks and Daniel Solander, during - Mesembryanthemum crassifolium Linnaeus Captain Cook’s first voyage and mapping of New Zealand 1753 – South Africa coastlines. Few years later, in their unpublished - Mesembryanthemum australe Aiton 1789 – manuscript “Primitiae Florae Novae Zealandiae” (in fact a New Zealand catalogue of plants collected in New Zealand between - Mesembryanthemum clavellatum Haworth 1769 – 1770) dated 1773 they state that the plant 1803 – Australia (Mesembryanthemum australe) is “abundant close to the sea especially in rock fissures near Tolaga, Opuragi, And this became a status quo for more than 100 years. Motuaro, Totaranui, New Zealand”. They eventually All three names are mentioned in Alwin Berger’s 1908 brought few live plants to Great Britain, and possibly to revision of Mesembryanthemaceae and Portulacaceae Kew. In 1786 Georg Forster published the name but [2]. He creates a group to accommodate these very failed a proper description so that the first who validly similar plants (Reptantia, not to confuse with the published the name (and possibly using for diagnose crustacean Suborder) also adding M. dunense Linnaeus cultivated Kew plants) was Aiton in 1789. He clearly 1753, from South Africa, to the group. One of the states that Mesembryanthemum australe was a New interesting aspects is the difference in the seed capsules Xerophilia – Anul I, nr. 2 (2) – Septembrie 2012 51 ISSN 2285 – 3987 appearance: according to A. Berger, while in the South African M. crassifolium the capsule is cone shaped, M. crassifolium and M. australe have “convex” and respectively “flat convex” capsules. Amongst other important morphologic differences – M. australe has the petals on two rows, while the others on a single row. Fig. 3 Bethels Beach - habitat Fig. 4 Bethels Beach - habitat In early New Zealand botanical accounts numerous Disphyma from all over New Zealand as well Mesembryanthemum australe was also recorded on as studying plants from the Chatham and Kermadec Lord Howe Island and Norfolk Islands. Chinnock [6] has Islands and I doubt very much if any other botanists (e.g. not found in his field trips any evidence, nor has listed Glen) have had access to so much material from so Turner the plant in his 1968 Norfolk Islands plant list. On many places. Therefore, I personally follow Bob whom the contrary, Chinnock believes that the plant was incidentally gave me samples of D. papillatum and D. originally confused with a smaller form of Carpobrotus australe subsp. stricticaule when I lived in Brisbane glaucescens, although the later one bears a very (however, very hard to maintain in that climate.)” distinctive berry-like fruit, so that all these accounts should be discarded. The genus Disphyma was established by N.E. Brown in 1925; however, despite a very precise diagnose he didn’t assign any species to the new created genus. But in 1930 he informally used the name Disphyma australe [10], it comes therefore a bit puzzling that few years later, in the monumental but quite selective tri-lingual work (English, German, Dutch) “Mesembryanthema” from 1931, N.E. Brown & al. [3] do not even mention Disphyma, not to speak of the three species, recombined or not. The first to formally recombine M. clavellatum and M. australe into the new genus was J.M. Black, in 1932. However, his taxon Disphyma australe J.M. Black 1932 was considered to occur in Australia, Tasmania, New Zealand and some other South Pacific islands and brings actually different forms into the mix. Mesembryanthemum crassifolium had been already recombined into Disphyma by L. Bolus in 1927. However, it took another three or four decades until the extensive field work of R.J. Chinnock shed new light on this complex. Although all his segregations are not widely recognized nowadays his work was the first to bring clarity and a sound classification. As D. Rowe [14] puts it: Fig. 5 Disphmya crassifolium subsp. clavellatum inland form “Bob Chinnock has of course done in depth studies of (Photo A. Kapitany) Xerophilia – Anul I, nr. 2 (2) – Septembrie 2012 52 ISSN 2285 – 3987 According to Chinnock [4] [5] [6], based on the capsule structures and on other floral or vegetative characters, there is a South African species - Disphyma crassifolium (Linnaeus) L. Bolus 1927 while the D. australe complex sensu J.M. Black consists of three different species: - Disphyma clavellatum (Haworth) Chinnock 1976 – refers to the Australian populations superseding Disphyma blackii Chinnock 1971, the name initially used to segregate all Australian populations. However, in 1986 Chinnock takes a step back recombining into Disphyma crassifolium ssp. clavellatum (Haworth) Chinnock 1986 and considering that Fig. 6 Disphyma australe - Tiritiri Matangi Isl. the Australian populations are not that different (Photo D. Rowe) to warrant a complete separation from the South African species [7]. This plant was also recorded in New Zealand, in the South Island having a pretty much localized distribution (Waimea Inlet and Riverton Estuary). Its flower is more or less bicolour, with purple petals having a whitish base. - Disphyma papillatum Chinnock 1971 – refers to the Chatham Islands populations. Although restricted to a rather small area the plant is quite variable in stem, leaf and flower pigmentation, but as a distinct character it has always acute leaf tips. - Disphyma australe (Aiton) J.M. Black 1932 Fig. 7 Disphyma crassifolium subsp. clavellatum inland sensu Chinnock, which is consisting of: forms (Photo A. Kapitany) o Disphyma australe (Aiton) J.M. Black 1932 ssp. australe – endemic to New Zealand and Chatham Islands. o Disphyma australe (Aiton) J.M. Black ssp. stricticaule Chinnock 1976 – endemic to the Kermadec group of islands, but also present (possibly introduced by man) in New Zealand. A very interesting feature of the cultivated plants of this subspecies is that the new stems have always an erected growing pattern for some time but becoming prostrate and spreading later on; this growth pattern was not observed at all in wild populations. Another distinctive feature is the 5 (only Fig. 8 Disphmya crassifolium ssp. clavellatum inland forms rarely 6) capsule valves. (Photo A. Kapitany) Xerophilia – Anul I, nr. 2 (2) – Septembrie 2012 53 ISSN 2285 – 3987 Although some important botanists seem to agree even in recent years with this classification (H.E.K. Hartman, 2000; and especially G.F. Smith & al. [15], 1998: “(…) overall the South African and Australian species do not seem particularly closely related”) Disphyma is widely considered a monotypic genus including all the above names plus few other minor or obscure taxons. Fig. 9 Disphyma australe Wilsons Bay (Coromandel) (Photo D.Rowe) Fig. 10 Manukau Heads However, during the early 1980’s H.F. Glen conducted populations occur [10] [13] [17] but it does with not so comprehensive studies and determined that based on closely related Carpobrotus species which suggests multivariate analysis (which is based on the statistical strange affinities with other members of the Ruschiae principle of multivariate statistics, involving observation tribe. and analysis of more than one statistical variable at a time) reached this conclusion. The results of Glen’s Purely from a C&S enthusiast’s point of view, all this makes studies might have had a huge influence on Chinnock’s me rather very cautious in considering the monotypic 1986 recombination. theory of Disphyma. On top of that – the dispersal range of the genus is quite strange and points rather towards an However, something is not quite right here. At some old gondwanic origin. Considering all the timings of the stage in the 1970’s R.J. Chinnock considered even super-continent break up there was enough separation creating a new genus in order to accommodate time between different groups that would allowed them a Disphyma australe, the reason behind being extremely certain independent evolution. Some sources [14] interesting. The etymology of the name Disphyma is consider the long range dispersal theory (with seabirds descriptive. Nick Perrin [10]: “The generic name, being the preferred vector – this seems almost ridiculous Disphyma, means “two-lumps”, and alludes the to me as it is pure convenience, unless you show me a presence of a two-lobed tubercle at the opening of each seagull consuming the dry capsules) when trying to explain seed-containing cell in the fruit.