Cirsium subcoriaceum (Less.) Sch. Bip. ex Seem. in Botany Voyage H.M.S. Herald 312 (1856). Carduus subcoriaceus Less. in Linnaea 5: 130 (1830). Type: Mexico, ‘in monte

Macultepec per. Jalapam’ Scheide €3 Deppe 265 (281 assigned herbarium number HAL).

Cirsium heterolepis Benth., PI. Hartw. 87 (1841). Type: Guatemala, ‘in montibus Mixco’ Hartweg 569 (K).

Cirsium maximum Benth., loc. cit. 289 (1849). Type: Mexico ‘in montibus Santa Rosa’ Hartweg 1837 (K).

Cnicus heterolepis (Benth.) A. Gray in Proc. Amer. Acad. Arts 10: 44 (1874). Cnicus subcoriaceus (Less.) Hemsley, Biol. Centr.-Amer. Bot 2: 252 (1881). Cnicus pinnutisectus Klatt in Bot. Beibl. Leopoldina 1895: 8 (1895). Type:

Cirsiumpinnatisectum (Klatt) Petrak in Beih. Bot. Centralbl. 27: 236 (1910). Costa Rica, Paramos de d’adjonal, 1,990 m, Tonduz 779 1 (GH).

REFERENCE

Dittrich, M. (1977). Cynareae - Systematic Review, in Heywood, V.H.; Harborne, J.B. and Turner, B.L. The Biology and Chemistry ofthe Compositae 11: 999-1015.

138. MEDUSAGYNE OPPOSITIFOLIA Medusagy naceae

Ann Robertson, Rosemary Wise and Frank White

Medusagyne ofpositzfolia, the sole member of its family, is one of about 80 species of plant endemic to the granitic Seychelles islands in the western Indian Ocean. The latter represent a continental fragment derived from the ancient super-continent Gondwanaland. Medusagyne is only known from MahC, the largest island. The flora and veg- etation of the Seychelles have recently been very briefly described within a framework of those of the African mainland as a whole and its other offshore islands (White, 1983).

The first visitors to the Seychelles, who recorded their impressions in the seventeenth century, saw giant trees and impenetrable jungles; with the exception of steep rock faces and coastal marshes, the whole of the islands constituted a forest habitat. For at least 200 years after the islands were discovered, timber cutting was one of the main industries, and, once cinnamon, Cinnamomum zeylanicum BI., had become established, cutting of fuelwood for the distilleries also led to the reduction of forest cover. However, despite this loss of original forests, and thanks to a more enlightened policy of vegetation con-

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Plate 138

Medusagyne oppositzjdia ROSEMARY WISE

servation over recent years, it is still possible to detect the altitudinal zones of vegetation described by Summerhayes (1931), Vesey- FitzGerald (1939), Sauer (1967) and Procter (1984).

The type locality of Medusagyne oppositifolia is the summit of Mount Sebert (550m) where J. Horne collected it in 1874. H.P. Thomasset obtained further specimens from this site in 1903 after which it was not seen again on Maht for many years and was thought to be extinct. In 1970, however, it was rediscovered by John Procter (No. 3991) who found six plants (Procter, 1970, 1974) grow- ing in clefts in the granite on Bernica, a small hill in west Mah6, where we (and others) have subsequently collected it (Robertson 2267 & 2482, Wise G' Chong Seng 18). In March 1986 one of us (RW) visited this site accompanied by the Seychelles Conservation Officer, Lindsay Chong Seng, and painted leaves and flowers as well as fruits of the previous season from the living plant. Bernica is now a strict nature reserve in the Morne Seychellois Forest National Park. Medusagyne oppositzfolia was also found again at the type locality in 1980 (Robertson &' Wilson 3 163A) and in 1982 a sterile specimen (G. de L'lsle s.n.), which had previously been overlooked, came to light at Kew; it had been collected on the plateau above la Mare aux Cochons in north-west Maht in 1876 but had been wrongly filed away as a Eugenia. It is thus possible that Medusagyne was formerly quite widely distributed, although restricted to particular conditions as is the pitcher plant, JVepenthespervillei B1.

Medusagyne oppositifolia occurs in the intermediate forest zone but is now so rare that it is not possible to say whether it was ever a common constituent of this vegetation type. It grows now in associ- ation with Pandanus multispicatus Balf. fil., Randia lancifolia (Baker) Hemsley, Dracaena rejlexa Lam., Deckenia nobilis Balf. fil., Memecylon eleagni Bl., Erythroxylum seychellarum O.E. Schultz and Dillenia fmruginea (Baill.) Gilg among others in the 'glacis' habitat described by Procter ( 1984, p. 20 1). Possibly fewer than ten trees are known to survive.

The etymology of Medusagyne and of its vernacular names bois meduse and jellyfish tree requires some explanation. In classical mythology Medusa (Greek Medousa) was one of the Gorgons, the three snake-headed sisters. In zoology, the word is also applied to the umbrella-shaped free swimming form of the class Hydrozoa and to a jellyfish (Coelentera). Fruits of Medusugyne were unknown to Baker when he coined the name SO he must have been implying a resem- blance of its pistil to the head of a gorgon. The fact that the dehisced

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fruit also resembles a larval hydrozoan and more remotely a jellyfish is a remarkable coincidence, justifying its comparison by Lucas & Synge (The IUCNplant red data book, 1978) to a Medusa-like parasol.

FLORAL BIOLOGY NATURAL REGENERATION AND CONSERVATION.

Nothing is known about pollination. In most inflorescences the flowers are of two kinds: male and bisexual. Previous authors have not mentioned this, except for Friedmann (Flews et arbres des Sqvchelles 89, 1986). The trees appear to flower and fruit profusely and the seeds are viable, but few, if any, seedlings survive in the wild. Although the two localities where M. oppositifolia is known to exist in Seychelles are protected, one of them is threatened by the con- struction of a dam for water supplies. I t would seem advisable for a specialist propagation unit to be set up in the Seychelles to initiate in situ propagation of this and other rare plant species, such as Vateria seychellaruum Dyer.

CULTIVATION. Attempts to grow this species from seed in Seychelles have failed. However, Henry Mathez, the gardener at the Botanical Garden in Berne was more successful (Synge, 1983). Seeds were sown immediately on arrival from Seychelles in a mixture of forest soil and peat to which spruce (Picea) needles, quartz sand and ‘Leca’ had been added. The pH was 5.5, and 5 grams of ‘Tardit’ fertilizer per litre of soil were used. The young plants had yellow or whitish curled leaves but this was cured by the addition of an iron mixture (‘Fe- EDTA’ with ‘Triton X-100’) and they were subsequently fertilized with ‘Waxal’ once a week. Whitefly (Trialeurodes vaporan‘um) was a problem and needed to be controlled. In the nursery a minimum temperature of 20°C was maintained and a relative atmospheric humidity of more than 70 per cent. In 1982, after two years, 57 plants had survived and some were available for sending to other gardens with collections of threatened tropical plants.

DESCRIPTION. Small tree up to 10 m tall with a rounded crown; trunk up to 20cm in diameter with dark, fibrous, striated bark; wood hard and dark brown. Leaves opposite, exstipulate, leathery and shiny, turning bright red on senescence; lamina elliptic or elliptic-oblong, glabrous, up to 8 cm long and 4 cm wide, often emarginate, margins crenate; secondary veins numer- ous, indistinct; tertiary veins forming a dense and prominent network on both surfaces; petiole up to 5 mm long. Flowers foetid, regular, hypowous, in lax cymose intlorescences at the ends of the branches, rather hidden by the leaves, male and bisexual, with both types usually present in the same inflorescence. Sepals 5, imbricate, united at the base, small, rounded, reflexed, persistent. Petals 5, free, convolute, white, sometimes suffused with

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C

E

Mednsagyne opposiiifolia. A, flower-bud, x 6; B, gynoecium and androecium of bisexual flower, longitudinal section, x 6; C, androecium of male flower, longitudinal section, X 6; D, anthers, x 25; E, part of ovary, transverse section, x 20; F, undehisced fruit, x 6; G, dehisced fruit, seen from outside, x 6; H, five carpels ofdehisced fruit seen from inside, x 6; I, seed (after Hemsley, 1906), x 12. Drawn by Rosemary Wise.

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pink, oblong, c. 5 mm long, at first spreading, later reflexed. Stamens numer- ous, free, marcescent in bisexual flowers; filaments very slender, slightly longer in male flowers; anthers somewhat variable, usually slightly apiculate, usually slightly asymmetric, opening by slits. O v a 9 superior, of up to 25 fused carpels, each with a shortly stalked capitate stigma which persists in the fruit; ovules 2 per locule; placentation axile. Fruits bright reddish brown, slightly woody, pendulous, subglobose, up to 1.5 cm long, verrucose, dehiscing from the base, each carpel spreading outwards to release the minute winged seeds from the opening inner margin; carpels of the dehisced fruit remaining attached to the apex of the central column like the ribs of an umbrella.

Little is known of the seed of Medusagyne. When Hemsley (1905) de- scribed the fruits collected by Thomasset in 1903 he could only find a single seed. Fruits collected subsequently have also shed their seeds, except for Wise

RELATIONSHIPS. Opinions on the relationships of Medusagyne are diverse (see below) and reflect its striking isolation due to the absence of any close relatives in any part of the world.

Without expressing any doubt, Baker (1877) placed Medusagyne in Tern- stroemiaceae (now Theaceae) . Hemsley ( 1905) was unable to propose an alternative but mentioned a combination of characters shown by Medusagyne which is otherwise unknown in Theaceae. He also described differences between Medusagyne and Guttiferae (Theales) to which a relationship had also been suggested. Engler & Gilg (1924) gave Medusagyne the status of a family and in the following year Engler & Melchior, in the most detailed account of Medusagynaceae to be published so far, thought that its position lay between Ochnaceae (Theales), with which it shares cortical vascular bundles, and Eucryphiaceae (Rosales in Conquist’s system). They also referred to the different opinions of some other workers who had mentioned an affinity with Quiinaceae (Theales), Linaceae (Linales) and Cunoniaceae (Rosales). To Theaceae and Guttiferae, Airy Shaw (see Willis, 1966 & 1973) added Myrtaceae (Myrtales) as possible relatives and commented on an analogy shown by the gynoecium of Medusagyne and that of Eucryphiaceae and the endemic New Caledonian family Paracryphiaceae (Theales) . After considering possible connexions with Theales and Rosales, Cronquist (198 1) placed Medusagynaceae in the former between Paracryphiaceae and Guttiferae (Clusiaceae) . He did, however, emphasize its uncertain relationships. The isolated taxonomic position of Medusagyne received enhanced prominence from Takhtajan (1986), who gave it ordinal rank, though still placing it next to Theales.

Chong Seng 18 (SEM photo. in FHO).

Medusagynaceae Engler & Gilg, Syllabus Pflanzenfam. (ed. 9-10) 280 (1924) nom. conserv.; Engler & Melchior in Engler & Prantl, Nat. Pflanzenfarn. (ed. 2) 21: 50 (1925); Hutchinson, Fam. F1. P1. (ed. 2) 1: 280 (1959); Melchior (rev.), Engler’s Syllabus Pflanzenfam. (ed. 12) 2: 160 (1964); Takhtajan, Systema Phyl. Magnoliophytorum 187 (1966); Cron- quist, Integr. Syst. F1. PI. 336 (1981).

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Mednsagyne oppositifolia Baker, F1. Maurit. Seych. 17 ( 1877); Oliver in Hook. Ic. P1. ser. 3, pl. 1252 (1878); Hemsley in Hook. Ic. PI. ser. 4, pl. 2790 (1905) and in J. Bot. Lond. 54, Suppl. 2, 4 (1916); Summerhayes in Trans. Linn. SOC. Lond. 2nd Ser. Zool. 19: 270 (1931); Procter in Candollea 29: 350, fig. 2 (1974); Friedmann, Fleurs et arbres des Seychelles 71, 88-89 (1986); Robertson, F1. P1. Seychelles 13 (1989). Type: Seychelles, Maht, summit ofMt. Sebert, 550m, J . Horne s.n. (holotype K).

DISTRIBUTION. Seychelles, Maht.; altitude 250-300 m.

REFERENCES

Baker, J.G. (1877). Flora of Mauritius and the Seychelles. London. Cronquis t, A. ( 198 1 ) . An integrated syftem of classij'ication ofJlowering plants.

Columbia University Press. Engler, A. & Gilg, E. (1924). 5jllabus der Pjanzenfamilien (ed. 9-10) 280.

Berlin. & Melchior, H. (1925). Medusagynaceae. In A. Engler & K.

Prantl (eds.) Die Natiirlichen Pjanzenfamilien (ed. 2) 21: 50-52. Hemsley, W.B. (1905). Medusagyne oppositifolia J.G. Baker. Hook. Ic. PI.

ser. 4, pl. 2790. Procter, J. (1970). Conservation in the Seychelles. Report of the Conservation

Adviser 1970. Government Printer, Seychelles. (1974). The endemic flowering plants of the Seychelles: an

annotated list. Candollea 29: 345-387. (1984). Vegetation of the granitic islands of the Seychelles. In

D.R. Stoddart (ed.), Biogeography and ecologv ofthe Seychelles islands 193-220. Junk, The Hague (Monogr. biol. voI. 55).

Robertson, S.A. (1989). Flowering Plants of Seychelles. Royal Botanic Gardens, Kew.

Sauer, J.D. (1967). Plants and man on the Seychelles Coast. University of Wisconsin Press.

Summerhayes, V.S. (1931). An enumeration of the angiosperms of the Seychelles Archipelago. Trans. Linn. SOL. London 2nd. Ser. Zoology 19:

Synge, H. (1983). Medusagyne - a propagation success. Threatened Plants Newsletter 1 1 : 9. Conservation Monitoring Centre, Royal Botanic Gardens, Kew.

Takhtajan, A.L. (1986). List offamilies of living vascular plants. In Floristic regions of the world 305-356. University of California Press.

Vesey-FitzGerald, D.F. (1940). On the vegetation of Seychelles. J . EGO/. 28: 465-483.

White, F. (1983). The vegetation of Africa: a descriptive memoir to accompany the UnescolAETFAT/UNSO vegetation map of Africa. Unesco, Paris.

Willis, J.C. (I966 & 1973). Adictionary of thejoweringplants andferns (eds. 7 & 8 - revised by H.K. Airy Shaw). Cambridge University Press.

261-299.

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