IAWA Journal, Vol. 19 (4), 1998: 393-413

WOOD ANATOMY OF TWELVE WITH POTENTIAL FOR REINTRODUCTION ON ROUND ISLAND, by

Peter Gasson1, Philip Jarvis1 & Wayne Page2

SUMMARY

Round Island is a nature reserve of great biological importance which once supported a dry evergreen hardwood forest and palm community. Following eradication of goats in 1979 and rabbits in 1986, restoration of the flora and fauna of the island is underway. Since the past compo­ sition of the hardwood community is unknown, wood sampies from dead trees on the island have been examined and identified. This paper describes eleven dicotyledons and one from Mauritius known or suspected to have occurred naturally on Round Island, and demonstrates the practical application of wood anatomy in the conser­ vation of an endangered flora. Key words: Diospyros egrettarum, Diospyros revaughanii, Dracaena concinna, Elaeodendron orientale, Eugenia lucida, Eugenia tinifolia, buxifolia, Gagnebina pterocarpa, Gastonia mauritiana, verticillata, Ochna mauritiana, Pemphis acidula, Mauritius, Round Is­ land, conservation, reintroduction, woody .

INTRODUCTION

Round Island is a nature reserve 22.5 km NE of Cap Malheureux, Mauritius, covering 151 hectares and rising to 280 m above sea level. It is of great biological importance, being the only relatively large Mascarene Island currently free of introduced mam­ mals, including rodents, and major woody weeds, whilst supporting a flora and fauna containing several species endangered or unknown elsewhere. These assets have not always been protected and much of the habitat originally found on Round Island has been destroyed. Prior to the 1800s Round Island supported both a dry evergreen hard­ wood forest and a unique palm community, the latter composed of Latania loddigesii, Hyophorbe lagenicaulis and Dictyosperma album var. conjugatum. During the 1800s, introduced rabbits and goats and subsequent damage caused by cyclones destroyed the hardwoods, seriously depleting the palm community (Merton et al. 1989). Eradi­ cation of the goats in 1979 and rabbits in 1986 (Merton 1987) now offers the possibil­ ity of restoring the flora and fauna of the island. In 1989 a management plan for the restoration of Round Island stated that a realistic goal was to restore the island's palm savannah and hardwood forest, thereby seeuring the future for the island's endan-

1) Jodrell Laboratory, Royal Botanic Gardens, Kew, Richmond, Surrey, TW9 3DS, United Kingdom. 2) Conservation Project, Mauritian Wildlife Fund, Wing B, 6th Floor, Ken Lee Build­ ing, Edith Cavell Street, Port Louis, Mauritius.

Downloaded from Brill.com10/08/2021 03:43:55PM via free access 394 IAWA Journal, Vol. 19 (4),1998 gered plants and animals, and becoming arefuge for a limited number of endangered Mauritian plants and animals. To achieve this goal nine specific objectives were pro­ posed for completion before 1999, one of which is to re-establish hardwood species formerly present on the Island (Merton et al. 1989). Latania, the dominant palm, is regenerating weIl (7-8,000 mature plants with many seedlings andjuveniles), whereas Hyophorbe is not doing so weIl (7 adults and 100 juveniles surviving). of Hyo­ phorbe have been distributed in this, the only locality for the species. Dictyosperma is surviving less weIl, with only one adult present and 25 juveniles having been intro­ duced on Ile aux Aigrettes, but not yet to Round Island. The past composition of the hardwood community on Round Island is unknown since specimens and records from the period prior to 1800 are poor. In order to estab­ lish this, it is necessary to examine and identify the wood of dead trees on the island. This paper provides a preliminary account of the wood anatomy of some taxa from Mauritius which could be suitable for colonisation of Round Island, inc1uding one monocotyledon (Dracaena concinna) and eleven dicotyledons, most of wh ich are known or suspected to have occurred naturallyon Round Island. These woods were used as reference material for the identification of six wood samples taken from dead trees on Round Island. Amongst previous wood anatomical descriptions of Mascarene taxa, Detienne &Jacquet (1993) described 70 species from Reunion, inc1uding two in this paper (Elaeodendron orientale and Nuxia verticillata) but only illustrated trans­ verse sections. Strahm (1989) provided a list of the woody plants of the dry low land zone of Mauritius that could be suitable for establishment on Round Island. The list consists of 103 species from 80 genera in 40 families. A complete account of the wood anatomy of aIl these species is beyond the scope of the current paper, particularly since we do not have wood sampies of many of them at Kew. Two of the woods remain unidentified. Two hardwood tree species remain on the island. Gagnebina pterocarpa survives as a few dying individuals found wild on the flanks of Corpe de Garde Mountain (5-600 m) and on the lIe aux Aigrettes, a corallitic island of 12 m. Their has not been observed to germinate. F ernelia buxifolia was c1early the last species forming the bulk of the hardwood forest, since the island is littered with entire dead skeletons of trees (2-2.5 m tall) in gullies and on open rock slabs. Only one 0.5 m tree growing out of a boulder survives.

MATERIALS AND METHODS

Wood samples were collected by one of us (Wayne Page) in Mauritius, along with sampies from dead trees on Round Island for identification. Permanent microscope slides were prepared from the Mauritian sampies, and vouchers were deposited at MSIRI (Mauritius Sugar Research Institute). Temporary slides were made of the Round Island sarnples for identification. One sampie was examined from each species (two in the case of ), and details of collecting locality, status and reintro­ duction potential are given with each ac count. The prefix 'MWF' refers to the Mauri­ tius Wildlife Fund, and 'Kw' to the Kew wood collection (see Stern 1988 for further details of the latter). The maximum diameter of each stern, with and without bark, is given where known.

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WOOD DESCRIPTIONS

Diospyros egrettarum LB.K. Riehardson (Ebenaeeae) - Fig. 1-5 MWF 4, Ile aux Aigrettes, 18.3.94. Stern diameter 61 mm with bark, 60 mm with­ out. For introduetion onee pioneers of other speeies have been established. Mauritian endemie. No published wood anatomical deseriptions found. Growth rings not seen, wood diffuse-porous. Vessels frequently in radial multiples up to 6, and oeeasionally in clusters, 41 % solitary. 19-31 (mean 26) per mm2, 17-56 (mean 40) J.Ull in diameter. Vessel element length 60-300 J.Ull (mean 200 J.Ull). Interves­ seI pitting fine (1.9-3.7 J.Ull), alternate, and polygonal. Vessel-ray pitting similar to in­ tervessel pitting, but less frequently polygonal. Perforation plates simple. Fibres thiek­ walled and septate. Fibre pits minute, slit-like, and present in both radial and tangential walls. Axial parenehyma very abundant in uniseriate tangential bands, and diffuse-in­ aggregates, approaehing retieulate in appearanee. Axial parenehyma strands 4 to 10 eells long. Rays 1-3 eells wide, up to 35 eells high, 14-22 (17) per mm, heteroeellu­ lar, eonsisting of proeumbent, upright, and square eells. Prismatie erystals present in ehambered axial parenehyma eells, and oeeasionally in proeumbent ray eells.

Diospyros revaughanii I.B.K. Riehardson (Ebenaeeae) - Fig. 6-11 MWF 14, Mare Longue Plateau (580 m), 24.8.95. Stern diameter 31 mm with bark, 29 mm without. A Mauritian endemie upland speeies, unlikely ever to have oeeurred on Round Island, but included here to improve eoverage of Diospyros speeies wood anatomy. Not one of the six speeies listed by Strahm (1989). No published wood anatomical deseriptions found. Growth rings not seen. Wood diffuse-porous. Vessels eommonly in clusters and ra­ dial multiples up to 4, some solitary (26%). Gum and resins found in many heartwood vessels. 23-25 (mean 24) per mm2, 21-49 (mean 33) J.Ull in diameter. Vessel element length 70-475 J.Ull (mean 300 J.Ull). Intervessel pitting fine (3.1-4.4 J.Ull), polygonal, alternate and in plaees opposite. Vessel-ray pitting alternate, oeeasionally polygonal, some vessel ray pits unilaterally eompound and eoarse. Perforation plates simple. Fibres thick-walled. Septate and non-septate fibres present. Fibre pits unbordered, present in tangential walls and to a lesser degree in radial walls. Axial parenehyma very abundant in tangential uniseriate bands, and diffuse-in-aggregates, approaehing retieulate. Axial parenehyma strands 4 to 5 eells long. Rays uni- or biseriate, the uni­ seriate and biseriate portions being the same width, rays 11-17 (14) per mm. Rays up to 30 eells high, heteroeellular, eonsisting of proeumbent eells with 10+ rows of marginal upright and square eells. Prismatie erystals present in ehambered and non­ ehambered axial parenehyma and in proeumbent ray eells.

Elaeodendron orientale Jaeq. (Celastraeeae) - Fig. 12-16 MWF 1, Brise Fer (540 m), 25.2.94. Stern diameter 176 mm with bark, 165 mm without. For introduetion onee pioneers established. Deseribed in Detienne & Jaequet (1993) as Cassine orientalis (Jaeq. f.) Kuntze. Some data in Areher & Van Wyk (1993).

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Growth rings indistinet at low magnifieation, not diseernible at higher magnifieation. Wood diffuse-porous. Vessels exclusively solitary and sometimes with an angular outline, 65-100 (80) per mm2, 17-70 (46) /llil in diameter. Vessel element length 555-1180/llil (mean 800 /llil). Intervessel pitting fine (2.5-4.4 !lIll), alternate, and widely spaeed. Vessel-ray pitting similar to intervessel pitting. Perforation plates sealariform with fewer than 10 bars. Fibres thick-/very thiek-walled. Fibres non-sep­ tate, with eonspicuous bordered pits present in both radial and tangential walls. Axial parenehyma in eontinuous tangential bands from 3 to 10 eells wide. Axial paren­ ehyma strands 4-10 eells long. Rays 1 to 8 eells wide, 16-20 (18) per mm, multiseriate rays frequently with long uniseriate tails. Uniseriate rays eonsisting of upright eells only. Multiseriate rays up to 45 eells high, heteroeellular, eonsisting of proeumbent eells with up to 20 rows of marginal square and upright eells. Prismatie erystals present in normal and enlarged ray eells.

Eugenia lucida Lam. (Myrtaeeae) - Fig. 17-21 MWF 3, lIe aux Aigrettes, 2.6.95. Stern diameter 35 mm with bark, 34 mm with­ out. A Mauritian endemie, for introduetion onee pioneers established. See note under Eugenia tinifolia. No published wood deseriptions found. Growth rings indistinet. Wood diffuse-porous. Vessels exclusively solitary, and often filled with gums and resins, 40-125 (100) per mm2, 7-33 (18)!lIll in diameter. Vessel element length 125-465 !lIll (mean 282 !lIll). Intervessel pitting fine (1.8-3.7 /llil) and alternate. Vessel-ray pitting similar to intervessel pitting. Perforation plates simple. Fibres thiek-walled. Septate and non-septate fibres present. Fibres with small but eonspicuously bordered pits, eommon in both radial and tangential walls. Axial parenehyma very abundant in tangential uniseriate bands, and diffuse-in-aggregates. Axial parenehyma strands up to 8 eells long. Rays uni- or biseriate with biseriate as wide as uniseriate portions, the eells in the biseriate portion being very small in eom­ parison to those in the uniseriate portion. Rays 19-25 (23) per mm. Rays up to 20 eells high, heteroeellular, eonsisting of proeumbent eells with up to 10 rows of mar­ ginal upright and square eells. Prismatie erystals present in ehambered axial paren­ ehyma eells.

Eugenia tinifolia Lam. (= E. mespiloides Lam., Myrtaeeae) - Fig. 22-25 MWF 13, Tourelle du Tamarin (300 m), 13.5.95. Stern diameter 32 mm with bark, 29 mm without. From Mauritius. Not mentioned as a possible introduetion in Merton et al. (1989), but Strahm (1989) stated that Eugenia requires further study before deeiding whieh speeies are most suitable for Round Island. No published wood deseription found. Growth rings present. Wood diffuse-porous. Vessels mostly solitary, oeeasionally in pairs, sometimes appearing to form tangential bands, 40-186 (121) per mm2, 7-43 (18) !lIll in diameter. Vessel element length 100-440!llll (mean 261 /llil). Intervessel pitting alternate, minute (1.8-3.8 !lIll), and oeeasionally widely spaeed. Vessel-ray pitting similar to intervessel pitting. Perforation plates simple. Fibres thick-waIled,

Downloaded from Brill.com10/08/2021 03:43:55PM via free access Gasson, Jarvis & Page - Woods from Mauritius 397 non-septate, and with tiny bordered pits common in both radial and tangential walls. Axial parenchyma diffuse-in-aggregates, and in uniseriate tangential bands, also in tangential bands up to 25 cells wide, probably of traumatic origin. Axial parenchyma strands up to 8 cells long. Rays uni- or biseriate, up to 20 cells high, 20-25 (22) per mm, heterocellular, consisting of procumbent cells with up to 8 marginal rows of square, and upright cells. Some ray cells with disjunctive end walls. Prismatic crys­ tals abundant in chambered and non-chambered axial parenchyma and fibres.

Fernelia buxifolia Lam. () - Fig. 26-30 Two samples: MWF 16, Tourelle du Tamarin (300 m), 13.5.95. Stem diameter 41 mm with bark, 40 mm without; K w 11111, Mauritius 170A-1886, Colonial & Indian Exhibition 1886. Only one tree remains on Round Island. No published wood anatomical descrip­ tions found. Growth rings very indistinct, only visible at low magnifications. Wood diffuse­ porous. A few vessels containing gums and resins. 83% of vessels solitary, the re­ mainder in pairs, 48-143 (76) per mm2, 12-46 (30)!Jffi in diameter. Vessel element length 70-631 !Jffi (mean 402 !Jffi). Intervessel pitting fine (1.8-5.6 !Jffi), alternate, and widely spaced. Vessel-ray pitting similar to intervessel pitting. Perforation plates simple. Fibres very thick-walled, non-septate, with minute slit like pits in both radial and tangential walls. Axial parenchyma diffuse-in-aggregates, and in discontinuous, uniseriate, tangential bands. Axial parenchyma strands varying in length from 2-10 or more cells long. Rays 1-3 cells wide, 1-40 cells high, 25-32 (28) per mm, hetero­ cellular, consisting of procumbent cells with up to 20 rows of marginal square and upright cells. Biseriate portions of the rays the same width or only slightly wider than the uniseriate portions. Some ray cells with disjunctive end walls. Crystals not present.

Gagnebina pterocarpa Baill. (= G. tamariscina De., Leguminosae-Mimosoideae) - Fig.3l-34. MWF 5, Ile Ronde (i.e. Round Island), 12.7.95. Stem diameter 41 mm without bark. Still exists on Round Island as a few dying individuals. No published wood ana­ tomical descriptions found. Growth rings distinct. Wood diffuse-porous. Vessels solitary (58%), in pairs, small clusters, and radial groups, some containing gums and resins. 0-39 (15) vessels per mm2, 34-109 (61)!Jffi in diameter. Vessel element length 45-360!Jffi (mean 132 !Jffi). Intervessel pitting vestured, mainly alternate, some opposite, and transitional (3.7- 8.4 !Jffi). Vessel-ray pitting similar to intervessel pitting. Perforation plates simple. Fibres thin- to thick-walled, many gelatinous, almost all non-septate, a very few having septa, all with simple minute pits in the radial walls. Fibres sometimes very thin-walled resembling axial parenchyma. Axial parenchyma vasicentric sometimes confluent. Axial parenchyma strands 1- or 2-celled. Rays 1-3 cells wide, 3-35 cells high, 4-10 (8) per mm, homocellular, consisting of procumbent cells only. Prismatic crystals present in chambered axial parenchyma cells and fibres.

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Gastonia mauritiana W. Marais (Araliaceae) - Fig. 35-39 MWF 6, Ile aux Aigrettes, 18.3.94. Stern diameter 40 mm with bark, 30 mm with­ out bark, of which 11 mm was pith. A Mauritian endemic and pioneer species for introduction. No published wood anatomical descriptions found. Growth rings distinct. Wood diffuse-porous. Vessel clusters common and some solitary vessels angular in outline, 22% solitary, 11-29 (21) per mm2, 17-72 (45) J.III1 in diameter. Some vessels the same diameter or narrower than ray cells. Tyloses present in a few vessels. Vessel element length 168-575 J.III1 (mean 350 J.III1). Intervessel pit­ ting alternate, transitional and scalariform (6.8-16.1 J.III1), the alternate pits being polygonal. Intervessel pits occasionally vestured. Vessel-ray pitting horizontally elon­ gated with reduced borders. Perforation p1ates simple. Fibres thin- to thick-walled, and non-septate, with simple, slit-like pits more common in radial walls. Axial paren­ chyma rare and scanty paratracheal, strands up to 8 cells long. Rays forming a sig­ nificant proportion of xylem, 1-5 cells wide and up to 30 cells high, 3-8 (6) per mm, heterocellular, consisting of procumbent, square and upright cells. Crystals not found.

Nuxia verticillata Lam. (/) - Fig. 40-44 MWF 2, Brise Fer (540 m), 12.5.94. Stern diameter 108 mm with bark, 105 mm without. An upland species, unlikely ever to have occurred on Round Island. Wood anatomy described by Mennega (1980), Detienne & Jacquet (1993) and Carlquist (1997). Growth rings very indistinct, visible only at low magnification. Wood diffuse-po­ rous. Vessels containing tyloses, gums, and resins. 68% of vessels solitary, 40-80 (62) per mm2, 17-48 (30) J.III1 in diameter. Vessel element length 56-160 J.III1 (mean 108 J.III1). Intervessel pitting fine (1.8-4.4 J.III1), alternate, sometimes widely spaced. Vessel-ray pitting similar to intervessel pitting. Perforation plates simple. Fibres very thick-walled and non-septate, with small bordered pits in both radial and tangential walls. Axial parenchyma diffuse and in discontinuous, uniseriate, tangential bands. Axial parenchyma strands up to 8 cells long. Rays 1-4 cells wide, up to 45 cells high, 20-24 (22) per mm, heterocellular, consisting of procumbent cells with up to 20 rows of marginal square and upright cells. Some ray cells with disjunctive end walls. Crys­ tals not present.

Ochna mauritiana Lam. (Ochnaceae) - Fig. 45-49 MWF 10, Tourelle du Tamarin (300 m), 13.5.95. Stern diameter 40 mm with bark, 38 mm without. For introduction once pioneers established. No published wood anatomical infor­ mation found. Growth rings indistinct. Wood diffuse-porous. Vessels mostly solitary, sometimes in pairs, and sometimes filled with resins and gums, 73-120 (91) per mm2, 12-56 (31) J.III1 in diameter. Vessel element length 70-390 J.III1 (mean 235 J.III1). Intervessel pitting alternate and minute (1.8-3.6 J.III1), sometimes with coalescent pit apertures. Vessel-ray pitting similar to intervessel pitting. Perforation plates simple. Fibres thick­ walled, non-septate, with slightly bordered slit-like pits very common in both radial

Downloaded from Brill.com10/08/2021 03:43:55PM via free access Gasson, Jarvis & Page - Woods from Mauritius 399 and tangential walls. Axial parenchyma in uniseriate tangential bands and diffuse-in­ aggregates, some scanty paratracheal, strands up to 8 cells long. Rays of two distinct sizes, 10-20 (14) per mm. Smaller rays mostly uniseriate and less than 20 cells high. Larger rays up to 8 cells wide and 80 cells high, often forming very large aggregate rays. All rays heterocellular consisting of procumbent, square, and upright cells, the larger rays usually having a layer of sheath cells. Prismatic crystals present in ray cells and non-chambered axial parenchyma cells. Crystals present in enlarged cells, occasionally more than one crystal per cello Styloid crystals also present in ray cells.

Pemphis acidula lR. & G. Forst. (Lythraceae) - Fig. 50-54 Kw 10475, Mauritius, no detailed location. A pioneer species for reintroduction. Grows especially on eroded beaches (Mab­ berley 1997). Wood anatomy described by Baas & Zweypfenning (1979). Growth rings present. Wood diffuse-porous to semi-ring-porous. Vessels solitary, in pairs, radial multiples of 3, and small clusters of 4. 50-96 (mean 74) % solitary, 14-30 (23) per mm2, 38-11 1 (65) j..U11 in diameter. Vessel element length 156-286 (210) j..U11. Intervessel pitting fine (1.8-6.8 j..U11), alternate. Vessel-ray pitting similar, some pits elongated and with coalescent apertures. Very fine, closely packed striations present on walls of some vessels. Perforation plates simple. Fibres thick-walled and non-septate, with inconspicuous pits in radial walls, many gelatinous. Axial paren­ chyma paratracheal, sometimes scanty, sometimes more abundant and confluent. Axial parenchyma strands 2-4-celled. Rays 1 or 2, occasionally 3 cells wide, often very short and 1-13 cells high, heterocellular, consisting mainly of square and upright and relatively few procumbent cells. Rays 5 -1 0 per mm. Ray cell walls strongly nodular, sometimes disjunctive. Crystals not seen.

Dracaena concinna Kunth (Dracaenaceae) - Fig. 55-59 MWF 7, Ile aux Aigrettes, 18.3.94. Stern diameter 90 mm. A pioneer species for reintroduction, introduced some years ago by Wendy Strahm and doing weIl. Small populations occur on the mainland, and the best viable regen­ erating population is on Ile aux Aigrettes. No published anatomical descriptions were found of this species, but Zimmermann & Tomlinson (1969, 1970) describe the pri­ mary and secondary vascular systems of D. jragrans. 'Wood' typically monocotyledonous (RudallI991, 1995), with scattered vascular bundles in parenchymatous ground tissue. Vascular bundles of inner stern randomly arranged, circular to oval in outline, with an incomplete fibre sheath on outer side of each bundle protecting the phloem. Ground tissue cells rounded in TS, often elon­ gated in LS, walls the same thickness as those of xylem elements. Xylem in an arc, sometimes separated into two regions, comprising 8-12 tracheary elements, with sca­ lariform pitting. Outer part of stern (within cortex) formed by secondary thickening meristem (STM), ground tissue consisting of radial files of squarish parenchyma cells. Vascular bundles radially elongated, without fibre bundle sheath, and 1-3 groups of phloem, sometimes surrounded by xylem. Xylem tracheary elements with circular pits with opposed apertures. Some ground tissue cells in all parts of stern contain raphide bundles.

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Fig. 1-5. Diospyros egrettarum (Ebenaceae). - 1 & 2: TS. - 3: TLS. - 4 & 5: RLS. - Scale line is 200 J.lIll for Fig. 1 & 4, 100 J.lIll for Fig. 2 & 3, 50 J.lIll for Fig. 5.

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Fig. 6-11. Diospyros revaughanii (Ebenacaeae). - 6: TS. -7: TLS. - 8: TLS, prismatic crys­ tals in axial parenchyma. - 9: RLS. - 10: TLS, intervessel pitting. - 11: RLS, vessel-ray pitting. - Scale line is 200 ).lII1 for Fig. 6, 7 & 9, 50 ).lII1 for Fig. 8 & 11, and 20 ).lII1 für Fig. 10.

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Fig. 12-16. Elaeodendron orientale (Celastraceae). - 12: TS. - 13 & 14: TLS. - 15: RLS.- 16: RLS, scalariform perforation plate. - Scale line is 200)lIll for Fig. 12, 13 & 15, 100)lIll for Fig. 14, and 50 )lIll for Fig. 16.

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Fig. l7-21. Eugenia lucida (Myrtaceae). - 17 & 18: TS. - 19: TLS. - 20: RLS. - 21: RLS, vessel-ray pitting. - Scale line is 200 !1Il1 for Fig. 17 & 20, 100 !1Il1 for Fig. 19, and 50 !1Il1 for Fig.18 & 21.

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Fig. 22-25. Eugenia tinifolia (Myrtaceae). - 22 & 23: TS. Note the wide band of probably traumatic parenchyma at top of Fig. 22. - 24: TLS. - 25: RLS. - Scale line is 200 ).lID for Fig. 22, 100).lID for Fig. 23-25.

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Fig. 26-30. Fernelia buxifolia (Rubiaceae). - 26 & 27: TS. - 28: TLS. - 29 & 30: RLS, some disjunctive ray cell walls in Fig. 30. - Scale line is 200 /JIIl für Fig. 26 & 29, 100 /JIIl for Fig. 27 & 28, and 50 /JIIl for Fig. 30.

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Fig. 31-34. Gagnebina pterocarpa (Leguminüsae-Mimüsüideae). - 31: TS. - 32: TLS. - 33 & 34: RLS. - Scale line is 200 ~ für Fig. 31, 100 ~ für Fig. 32 & 33, and 50 J..Ull für Fig. 34.

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Fig. 35-39. Gastonia mauritiana (Araliaceae). - 35: TS. - 36: TLS. - 37: RLS. - 38: RLS, vessel ray pitting. - 39: TLS, intervessel pitting. - Scale line is 200!lill for Fig. 35-37, and 50!lill for Fig. 38 & 39.

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Fig.40-44. Nuxia verticillata (Loganiaceae). - 40: TS. - 41 & 42: TLS. - 43 & 44: RLS. - Scale line is 200 fJIl1 for Fig. 40, 41 & 43, and 100 fJIl1 for Fig. 42 & 44.

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Fig. 45-49. Ochna mauritiana (Ochnaceae). - 45 & 46: TS. - 47 & 48: TLS. - 49: RLS. - Scale line is 200 f.lII1 for Fig. 45, 47 & 49, and 100 f.lII1 for Fig. 46 & 48.

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Fig. 50-54. Pemphis acidula (Lythraceae). - 50: TS. - 51 & 52: TLS. - 53 & 54: RLS. - Scale line is 200 llIl1 for Fig. 50, 51 & 53, and 100 llIl1 for Fig. 52 & 54.

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Fig. 55-59. Dracaena concinna (Dracaenaceae). - 55: TS, prirnary vascular bundles in inner stern. - 56: TS, secondary vascular bundles in outer part of stern. - 57: LS, ground tissue. - 58: LS, scalariforrn pitting. - 59: LS, raphide crystals in idioblast. - Scale line is 200 ~ for Fig. 55-57, and 20 f.UTI for Fig. 58 & 59.

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WOOD IDENTIFICATIONS

Examination of the material for this paper enabled us to identify four out of six wood sampies from dead trees on Round Island. These match our reference material and descriptions of Fernelia buxifolia (two sampies), Gagnebina pterocarpa and Pemphis acidula.

DISCUSSION

This paper demonstrates how wood anatomy can have practical applications in the conservation of an endangered flora. Our identifications confirm the past presence of three taxa on Round Island and provide support for their reintroduction. A knowledge of the woody species that grew on Round Island provides a basis to begin restoring the island's habitats, but problems remain. There is a lack of shade outside the palm community, and no free standing fresh water on the island, so pioneer plants will be necessary to initiate soil stability and provide organic debris before full reintroduc­ tion takes place. Some introductions have already taken place with varying success. Transplants of Dracaena concinna are recolonising well, and the most successful seedling transplants have been of Gastonia mauritiana. Seed trials of Pemphis acidula and Scaevola taccada in the last ten years have met with poor results, although one shrub and several seedlings of the latter are doing quite weIl. Seed and seedling trials of Diospyros egrettarum are less encouraging, except for the establishment of one tree, and small transplants of Eugenia lucida have failed. Ehretia petiolaris andArgusia argentea have not yet been tried, nor have several of the species described in this paper, inc1uding Fernelia buxifolia, Gagnebina pterocarpa, Ochna mauritiana, and Elaeodendron orientale. In the future, more wood sampies from Round Island will be examined to help c1arify what on ce grew there and increase the number of species for possible reintro­ duction.

ACKNOWLEDGEMENTS

We would like to thank Mary Gregory, Paula Rudall and Tim Lawrence, who advised on past litera­ ture and suggested many improvements to the manuscript. Permission to collect material was kindly given by Yousoof Mungroo, the Director of National Parks and Conservation Service, Government of Mauritius.

REFERENCES

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