646. CYLINDROCLINE LORENCEI Compositae Plant in Peril, 31 Nicholas Hind, Michèle Sánchez and Carlos Magdalena Summary. Cylindrocline lorencei A. J. Scott, a ‘Plant in Peril’, is described and illustrated, and its cultivation requirements provided. The species’ conservation status is commented on: once declared extinct in the wild, attempts have now been made to re-introduce the species into Mauritius. The relationships of Cylindrocline are discussed. The subject of this plate, the Mauritian Cylindrocline lorencei A. J. Scott (Compositae: Inuleae) is, like the other species in the genus (Cylindrocline commersonii Cass.), a botanical curiosity. It attains horticultural merit with age as an architectural plant that has a good bark structure and interesting leaves, as well as being relatively pest free (q.v. Hind, 1996). It does have one point of considerable interest, hence the subtitle of this paper as a ‘Plant in Peril’, in that it is extinct in the wild. Its existence in cultivation has provided a success story, both in terms of its continued propagation and its eventual repatriation to Mauritius, for the Royal Botanic Gardens, Kew. Cylindrocline Cass. was placed in the tribe Inuleae Cass. (including the everlastings, edelweiss and cudweeds) by Cassini (1817). Bentham’s broad treatment of the Inuleae (Bentham, 1873) included nine subtribes which he considered a well-defined group. Anderberg aimed to ‘refute this taxonomic misconception’ (Anderberg, 1989, 1991c) along with Bremer (1987) and, in a short series of papers (Anderberg, 1991a; 1991b; 1991c), sought to divide the Inuleae sensu lato into three tribes, the Inuleae Cass. sensu stricto, Gnaphalieae (Cass.) Lecoq & Juillet and the Plucheeae (Benth.) Anderb. As the result of cladistic analyses, of predominantly morphological characters, Cylindrocline was found to be ‘sister’ to the rest of the tribe Plucheeae as recognised by Anderberg (1991c), i.e. basal to the rest of the tribe. The separate tribes were presented by Bremer (1994). However, matters are slowly turning full circle, and molecular systematics has proposed that the genera of the Plucheeae are nested within the Inuleae (cf. Funk et al., 2005; Anderberg & Eldenäs, 2007), albeit based on a rather poor sampling (c. 14% 120 Curtis’s Botanical Magazine 2009 vol. 26 (1&2): pp. 120–130  The Board of Trustees of the Royal Botanic Gardens, Kew 2009. Plate 646 Cylindrocline lorencei renato moraes of genera). The more recent analysis of the Inuleae sensu lato (i.e. including the Plucheeae) has placed Cylindrocline, along with the bulk of the so-called core genera of the Plucheeae (e.g. Coleocoma F. Muell. – 1 sp., Doellia Sch.Bip. ex Walp. – 2 spp., Epaltes Cass. – c. 14 spp., Karelinia Less. – 1 sp., Laggera Sch.Bip. ex Koch, p.p. – 17 spp, Pluchea Cass. – c. 80 spp., Porphyrostemma Benth. ex Oliv. – 4 spp., Pseudoconyza Cuatrec. – 1 sp., Sphaeranthus L. – c. 40 spp., Streptoglossa Steetz – 1 sp., and Tessaria Ruiz & Pav. – 1 sp.), in a comblike polytomy (Anderberg et al., 2005). None have any particular horticultural merit. One of the authors (N.H.) still prefers to recognise a broader concept of the Inuleae (Hind, 2007) within which Cylindrocline is still placed, recognising the three subtribes Inulinae, Gnaphaliinae Less. and Plucheinae Benth. Obvious generic relationships of Cylindrocline have become far less clear with each new set of analyses. Originally, Cassini (1822) placed Cylindrocline in his ‘Inulées-Prototype’ in a group of four genera with paleaceous receptacles – Rhanterium Desf., Molpadia Cass. (= Buphthalmum L.) and Neurolaena R. Br. (now in the Heliantheae Cass.). Bentham (1873), in his broad concept of the Inuleae, placed our genus in the subtribe Filaginae Benth., along with Blepharispermum Wight ex DC. and Athroisma DC. based upon achene characteristics. Both of the latter are sometimes placed in the tribe Athroismeae Panero. The more recent analyses of Anderberg (1991c) and Anderberg et al., (2005) suggest no close allies, indicating that the genus should be treated as somewhat isolated. In the earlier special issue of Curtis’s Botanical Magazine (Volume 13, Part 4, 1996) dealing with the Mascarene Islands, Wendy Strahm provided an assessment of the need for conservation on the islands (Strahm, 1996). The incredible richness of the flora, in terms of endemics (73% of flowering plants, 22% of pteridophytes) was emphasised, as well as the number of plants now considered extinct – 80 species on Mauritius alone. In tabulating the ‘top thirty’ threatened plants of Mauritius’, Cylindrocline lorencei was listed noting, regrettably, that there was only ‘One shrub which has since died’. It was last known alive in the Black River Gorge National Park, Mauritius. The subject of the present plate is one large stock plant that has been growing at Kew since 2001 in the Temperate Unit of the  The Board of Trustees of the Royal Botanic Gardens, Kew 2009. 123 Tropical Nursery; there are several other plants at Kew, from the original clone and subsequent propagations from our stock plant. Cultivation. Achenes from the one remaining plant in Plaine Champagne, Mauritius, were collected by Jean Yves Lesouëf in 1980. Germination tests in the Conservatoire Botanique National de Brest in 1994 and 1995 were failures. However, newly developed techniques, to grow the embryos in vitro, resulted in three clones which, when grown on, produced seeds in 2003. The fact that any live material was found in the achenes resulted from a series of staining experiments in Brest. Small clusters of live cells were found in very few seeds when extracted from the achenes, leading to the production of three clones. The Royal Botanic Gardens, Kew accession is a donation from 2001 by Conservatoire Botanique National de Brest from one of the clones. Cylindrocline lorencei is a tender shrub, requiring, for cultivation in Great Britain, a temperate glasshouse, with a minimum temperature of 8◦ C. No supplemental lights or humidity are necessary. At The Royal Botanic Gardens, Kew it is grown in Zone 1 of the Tropical Nursery. Relative humidity is ambient, and ventilation is improved by the use of top fans hung over the benches, as well as roof vents. Temperatures can reach 28–30◦ C in summer. Irrigation water is treated by a reverse osmosis process, which neutralises pH and removes dissolved salts. Good plant growth and health were achieved using well-drained multipurpose compost based on a loam/coir/Perlite medium with added slow release fertiliser. Soil should be allowed to almost dry between watering. Plants do not respond well to water-logging. Feeding with a well balanced fertiliser (NPK) is carried out every fortnight. They flower well in summer. Pests. The plants are relatively pest free, with occasional minimal occurrence of mealy bug. Mechanical pest control is recommended, as plants are very sensitive to chemical foliar sprays and are scorched when chemical sprays are applied. Propagation. Propagation by seed has been unsuccessful at Kew, possibly due to a self-incompatibility problem. The seed produced by selfed plants appears not to be viable. Propagation can be achieved by tissue culture or cuttings. Cuttings are difficult and slow to root, sometimes taking up to four months. Successful apical cuttings can be taken in the spring when they are potted into equal parts of 124  The Board of Trustees of the Royal Botanic Gardens, Kew 2009. Fig. 1. Cylindrocline lorencei. Habit sketch of mature plant cultivated at RBG, Kew. Drawn by Renato Moraes. peat/Perlite (70:30) and placed in a cabinet on a heated bench with a minimum temperature of 20◦ C. As soon as rooted, they are potted on into a loam/coir/Perlite mix and transferred to a cooler zone. Tissue culture has proved to be the most efficient method to propagate this species. Plants were weaned into a coir/Perlite (70:30) mix when 1–2 cm or more in size inside a closed propagator on a heated bench for 1–2 weeks. Reintroduction and repatriation. In 2006, micropropagated plants in jars were repatriated, featuring in a headline article on  The Board of Trustees of the Royal Botanic Gardens, Kew 2009. 125 ‘Conservation’ in Kew Scientist (Issue 29, April 2006). Unfortunately the plants failed to establish during the weaning process on Mauritius. In another attempt, in March 2007, 12 mature plants (about 60 cm tall) were repatriated by one of the authors (C.M.). This repatriation was successful and a year later some were still growing at the Native Plant Propagation Centre at Currepipe, Mauritius. However, the climatic conditions at this nursery are not ideal for this species, as Cylindrocline lorencei grew at a higher altitude than the lowland, and more tropical, Currepipe facility. Cylindrocline lorencei A. J. Scott in Kew Bull. 42(2): 476 (1987). Type: ‘Mauritius. Plaine Champagne, low thicket heath community, Lorence 15532’.[Plaine Champagne (along road to Bel Ombre Nature Reserve c. 1/ mile from main road). Shrub 5 feet tall in low thicket heath community. 4 Flowers violet mauve, leaves olive green. 15. 1. 73. Lorence 15532.] Holotype: MAU; isotypes: MAU (see note below), MO. Illustration: Flore des Mascareignes, 109: 48, pl. 14 (1993). Description. Treelet or small tree to 2 m. Trunk to c. 7.5 cm diameter at base, sparsely to moderately well-branched above and densely leafy in terminal rosettes (these far denser and conspicuous in herbarium material). Stems at first densely lanate, later becoming glabrescent and conspicuously marked with scars of fallen leaves, older leaves retained when dead (at least in cultivated material where they are easily removed by hand but clearly do not fall). Leaves spiralled, distinctly rosettiform (in the wild) or forming a very loose rosette towards branch apices or simply leafy upper stems (in cultivated material), sessile to short-petiolate, petiole 10–15 mm long, lamina oblanceolate, 120–180 (–200) mm long by (37–) 45–55 ( −60) mm wide, olive green (to ‘golden tomentose’ – Lorence 2196) and slightly discolorous and lighter beneath, indumentum above uniform and densely velutinous beneath, areolae densely pale brown to off-white velutinous but over venation dirtier ambercoloured lanate indumentum with much longer, contorted hairs, all trichomes eglandular, uniseriate and often conspicuously septate, base cuneate, primary venation yellowish-green above and beneath, secondary venation insculpate above, prominent beneath, margins entire, apex acute. Inflorescence terminal but rapidly overtopped by axillary vegetative growth (in cultivated material), one to few per shoot per season, peduncle to 14 cm long (usually much shorter in herbarium material), basal section below first leaf-like bract c. 5.5 cm, all densely lanate, eventually peduncles pendulous by fibres of retted peduncle. Capitula heterogamous, disciform, sessile and often forming small glomerules at apices of inflorescence branches; involucre cylindrical, 12–14 mm tall by c. 5 mm diameter; phyllaries 5-seriate, 5 mm long by 2 mm wide, midribs often somewhat keeled, margins conspicuously long-ciliate, apices acute, with tuft of long, often crisped hairs usually over a lilac (in fresh material) or purplish (in dried material) apical blotch; receptacle conical, paleaceous, paleae linear-lanceolate, pale brown 126  The Board of Trustees of the Royal Botanic Gardens, Kew 2009. G M J D H E L F K A B C Fig. 2. Cylindrocline lorencei. A, capitulum; B, outer phyllary; C, inner phyllary; D, l.s. capitulum; E, palea; F, marginal female floret; G, disc floret with accompanying palea; H, corolla, anther cylinder and style of disc floret; J, corolla of disc floret opened out showing attachment of anther filaments and complete style; K, apices of achene setulae, much enlarged; L, apex of pappus seta of female floret, much enlarged; M, apex of pappus seta of disc floret, much enlarged. Scale bars: A, D = 5 mm; B, C, E, F, G, H, J = 1 mm. Drawn by Renato Moraes from living material in RBG, Kew.  The Board of Trustees of the Royal Botanic Gardens, Kew 2009. 127 or straw-coloured and often purplish towards apices, margins long-laciniate. Marginal florets female, corollas filiform, 3 mm long, short-dentate, sparsely short stipitate-glandular and glandular-punctate about apex; style base lacking basal node, narrowing from base upwards, glabrous, exserted, style arms c. 0.8 mm long, lilac, short-pubescent, hair apices acute. Disc florets hermaphrodite, at first male later becoming female, corollas purplish, tubular, 3–4 mm long, fused to apex of achene, 5-lobed, lobes c. 1 mm long, conspicuously glandular outside, apices obtuse and somewhat thickened; anther cylinder exserted, apical anther appendages triangular, apices acute, basal anther appendages short-tailed; style base lacking basal node, but with annular nectary, glabrous, style arms c. 0.8 mm long, lilac, short-pubescent, hair apices acute. Achenes triquetrous and with a broader flatter face outside(marginal florets) to cylindrical and c. 8-ribbed, (disc florets), 3–3.5 mm long, brownish, body sparsely setuliferous on angles towards apex, setulae of twin-hairs, apices asymmetrical and scarcely divided, one apical cell conspicuously bigger than other, fine-acute; carpopodium an inconspicuous narrow basal flange; pappus setae 8–12 (often fewer in marginal florets), usually appearing uniseriate but clearly biseriate on some disc achenes, 3–4 mm, setae free, flattened with laciniate margins (originally described as plumose!) (Figs 1 and 2). Distribution. Mascarenes: endemic to Mauritius, before it became extinct, on the Plaine Champagne. Habitat and Ecology. Growing amongst low ericoid scrub with Philippia and Helichrysum, on lateritic soil; 700 m. Flowering time. December to January, and June in Mauritius; June to July in cultivation, but is somewhat variable. Conservation status. When Lorence collected the material used by Scott as the holotype (1973), he noted that there was only one plant in the Plaine Champagne. Lesuoëf’s collection of fruits in 1980 confirmed the continued existence of this plant. At this point the species could have been classed as Endangered. However, Strahm’s note (Strahm, 1996) recorded that the plant had died: the species at that point would be recorded as Extinct. The plant was considered extinct in the wild in 1990 yet the ‘1997 Red List’ (Walter & Gillett, 1998) still recorded the species as Endangered. Although a number of plants have been repatriated to Mauritius it still remains to be seen if these will survive in the Native Plant Propagation Centre at Currepipe and, if replanted in their original habitat, will continue to grow in the Plaine Champagne. Although aspects of the capitulum and its florets have been recorded, nothing has been recorded of the biology of the developing capitulum. The first author was alerted to the stock plant flowering by the artist Renato Moraes, who has painted the subject of this plate. Upon investigation the capitula were found to go through the following cycle. The outer florets are filiform and female, the styles a pinkish lilac matched by the apices of the innermost phyllaries; the disc portion of the capitulum is still green at this point and no other structures are visible. After a few days the first of the inner, scattered outer disc florets begin to open in a spiral. These have purplish corollas and are at first male with the pollen mass being forced out of the top of the anther cylinder as the style grows. 128  The Board of Trustees of the Royal Botanic Gardens, Kew 2009. In some, as the style begins to grow up through the anther cylinder, the anther cylinder is forced over sideways. The disc florets then gradually become female as the style grows through the anther cylinder and the style arms separate. Whilst most of the ‘recent’ collections of Cylindrocline lorencei have been made since the mid-1970s, the earlier collections date from Blackburn’s in the 1860s, Bojer’s from the 1830s, and apparently the earliest, that of Du Petit-Thouars from the 1790s. It is likely that both the two latter collections were mixtures of C. commersonii and C. lorencei, vide Du Petit-Thouars s.n., s.loc. (P). It is worth drawing attention to the protologue statement by Scott (1987), in the material examined, that the holotype was ‘MAU, 2 sheets’. Many years ago the first author examined these sheets when they were photographed for record. It is quite clear that only one sheet is actually labelled as the holotype and that the other is a similar sized specimen merely determined by A. J. Scott; its type status was not indicated. This second specimen is merely a duplicate and not indicated as part of the holotype; it is to be counted as an isotype. This second specimen possesses a habit sketch drawing, by Lorence, pinned to the sheet, together with a small portion of bark from the trunk. Key to the species of CYLINDROCLINE (translated from Scott, 1993) Leaves narrowly oblanceolate, to 14 cm long, ± discolorous and slightly paler beneath, apices acute; peduncles 1 to few, to 14 cm long . . . . . . . . . C. lorencei Leaves spathulate, oblanceolate to obovate, to 7 cm, conspicuously discolorous and white woolly beneath, apices obtuse or broadly acute; peduncles few to numerous, to 6 cm long . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C. commersonii Acknowledgements. The authors would like to thank Renato Moraes, the 18th Artist Scholar of the Margaret Mee Fellowship Programme, for producing the colour plate, text habit figure and the black and white dissections, whilst under the tutelage of Christabel King during his scholarship in 2006. REFERENCES Anderberg, A.A. (1989). 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