Vegetation and checklist of Inaccessible Island , central South Atlantic Ocean , with notes on Nightingale Island

The physiography and climate of Inaccessible and Nightingale Islands are briefly discussed. The vegetation and the major plant associations are described. Notes are given on the ecology and distribution of each taxon. Taxa newly recorded for Inaccessible Island include Agrostis goughensis, A.holgateana, A. wacei, Calamagrostis deschampsiiformis, Carex thouarsii var. recurvata, Conyza albida, Elaphoglossum campylolepium and Uncinia meridensis. One species, C. albida, is alien to the Tristan group. Two native ferns Asplenium platybasis var. subnudum and Blechnum australe were found on Nightingale Island for the first time, and the presence of introduced Malus domestica orchards was recorded. Two unidentified taxa were found that may represent new species: Elaphoglossum sp. at Inaccessible Island and Apium sp. at both Inaccessible and Nightingale Islands. The total number of vascular plant species recorded at Inaccessible and Nightingale Islands now stands at 98 and 43, respectively, of which 26 (28%) and seven (16%) are introduced species. Only Airiplex plebeja and two species of Cotula occur at Nightingale Island but are absent from Inaccessible Island.

metric surveys of the coastal waters suggest that the islands are remnants of once much larger islands (Baker et al. 1964).Lavas from Inaccessible Island have been dated at approximately three million years old, whereas Nigh tingale Island originated approximately 18 million years ago (Gass 1967;McDougall & Oilier 1982).The geology of the islands has been described by Baker et al. (1964).Inaccessible Island consists of thin basaltic lava flows interbedded with ash and cinders, with intrusive trachyte dykes, plugs and domes.Nightingale Island, being older, is more extensively eroded, and consists almost entirely of trachytes.
Inaccessible Island has a planar area of approximately 12 km: (Preece et al. 1986. contra Siddall 1985).It is surrounded by sheer cliffs which are 500 m high in the west and 200 m in the east (Figure 1).The plateau is undulating, with three main drainage basins and a few small hills, the highest being Swale's Fell.511 m (Figure 2).Nightingale Island has a planar area of approximately 3 km2 and is lower-lying than Inaccessible Island, the highest peak being approximately 370 m (Wace & Hold gate 1976).There are no permanent streams on Nigh tingale.but there are three bogs (The Ponds) in the central part of the island (Figure 3).

MIDDLE ISLAND
POINT the climate near sea level is probably similar to that record ed at Tristan da Cunha, 40 km away (see Wace & Holdgate 1976).Mean daily minimum and maximum temperatures measured during October 1989 and December to March 1989-90 at Blenden Hall, ± 10 m above sea level at Inaccessible Island, were 14.0°C and 21.6°C (range 7.5-28°C).Temperatures on the plateau are consider ably cooler than those at the coast.Relative humidity at Blenden Hall varied between 52% and 100% (mean 82.5%).The prevailing winds are from the west, and there is often a marked altitudinal variation in wind strength; winds are stronger on the plateau than along the coast.
Rain is typically associated with the passage of frontal systems and occurs throughout the year, with a winter maximum (Wace & Holdgate 1976).The mean rainfall at Blenden Hall, Inaccessible Island was 151 mm per month during summer, uith at least some rain on 73% of days.Rainfall on the plateau was approximately one-third higher than that recorded near sea level, and precipitation on the plateau is higher still due to the frequent formation of orographic clouds (typically above 350m).Orographic cloud covered the top of Inaccessible Island on 50.4% of days during summer 1989-90.Nightingale Island.22 km distant from Inaccessible Island, presumably has a similar climate to that at Inaccessible.However, being a lower is land, Nightingale has less marked altitudinal variation in climate, and has orographic cloud cover less frequently than does Inaccessible Island.

VEGETATION
The origin of the floras of isolated, geologically young islands by means of long distance dispersal has been discussed extensively (e.g. Tryon 1966;Carlquist 1980: Huntley 1967;Wace 1960).The main dispersal vectors of propagules to the Tristan islands are transport by wind, birds and ocean currents (Wace & Dickson 1965).The origin of the Tristan flora is primarily South American or southern circumpolar (Wace & Dickson 1965;Tryon 1966).Preece et al. (1986) Dickson (1965).We recognize four physiognomically distinct types of vegetation or formations (Figures 4 & 5), which can be divided into several communities charac terised by different dominant species.The communities are used as a unit of description and can be grouped in their formations as follows: 1, tussock grassland: Spartina arundinacea tussock; Blechnum penna-marina heath.2, fern bush: Blechnum palmiforme heath; Phylica arborea bush.3, wet heath.4, bogs: Sphagnum bog; Scirpus sulcatus bog.

Spartina arundinacea tussock
On Inaccessible Island this community forms extensive stands on the small areas of flat ground at sea level and on all the steep sea-facing cliffs up to ± 500 m (Figure 6).It penetrates the plateau only in the low-lying river val leys above the Waterfall and Cave Rock.In areas of tall, dense growth, the closely spaced tussocks exclude all other vascular plants.
On drier, better drained ridges and in marshy areas the tussocks are more widely spaced, allowing multi-species communities to form.The species more commonly found on ridges and slopes include Blechnum australe, B. pennamarina, Elaphoglossum laurifolium, E. succisifolium, Rumohra adiantiformis, Empetrum rubrum and Nertera depressa.In marshy areas Amauropelta bergiana var.Small streams and seepages run down the steep slopes onto the boulder beaches with Azolla filiculoides, Plantago major and Rumex obtusifolius subsp.obtusifolius commonly occurring on the streambanks.Apium australe and Sonchus oleraceus are common on the eroded talus slopes above the beach between Dirleton Point and Warren's Cliff.Rockhopper penguins (Eudyptes chrysocome) erode paths in their colonies under the tussock, resulting in some tussocks standing on a root pillar up to 300 mm high.Phylica arborea scrub occurs on some slopes and ridges.These plants never flower and usually adopt the height of the surrounding vegetation as a result of the exposed, wind swept habitat.

Phylica arborea bush
This association is lately confined to the more sheltered eastern part of Inaccessible Island at elevations of ± 150-250 m.Moving from B. palmiforme heath, the initially procumbent Phylica arborea scrub becomes progressively taller, until it eventually forms a closed canopy up to 5 m high in well sheltered localities (Figure 8).P. arborea branches support dense growths of epiphytic lichens and some ferns such as Hymenophyllum aeruginosum.The undergrowth consists largely of dense stands of pteridophytes with Blechnum palmiforme, Ctenitis aquilina and Histiopteris incisa var.carmichaeliana the dominant species, although Elaphoglossum laurifolium and Asple nium obtusatum var.crassum form monospecific stands in places.In some areas with dense canopy cover, there is little understorey vegetation, and the ground is exten sively burrowed by breeding great shearwaters.
The Serengeti, a flat, relatively dry region in the centre of Inaccessible Island, consists of open P. arborea wood land.B. palmiforme, which attains a height of up to 2 m, forms a subcanopy between the trees.The ground storey is sparse, with Eriosorus cheilanthoides, Carex thouarsii var.thouarsii, Empetrum rubrum, Nertera depressa, Scirpus bicolor var.bicolor and various mosses the most abundant species.Several taxa are very scarce or absent in this area including all grasses, Acaena sarmentosa, Ctenitis aqui lina, Lagenophora nudicaulis and Gnaphalium thouarsii.
Phylica arborea trees also occur in tussock grassland on the coastal slopes of Inaccessible Island, and are absent only between Dirleton Point and South Hill.Trees occur singly, in small groups, and occasionally in larger groups with closed canopies (such as Wilkins' Copse, east of Skua Bog at the West Pbint of Inaccessible Island).These trees differ markedly from those on the island plateau.There are very few epiphytic lichens on the branches (presumably due to the infrequency of precipitation from mist and clouds at lower altitudes) and the understorey consists either mainly of Spartina arundinacea or has a composi tion similar to Blechnum penna-marina heath.
On Nightingale Island, closed-canopy Phylica arborea bush is confined to the vicinity of The Pbnds.In damp areas the undergrowth consists largely of Blechnum palmiforme and Scirpus bicolor var.bicolor, but the drier slopes support Ctenitis aquilina, Hypolepis rugosula var.villoso-viscida, Histiopteris incisa var.carmichaeliana, Carex thouarsii var.thouarsii and Acaena sarmentosa.Scattered P. arborea also occurs in tussock grassland, particularly along drainage lines on the eastern peak.In open areas around the Ponds, Scirpus bicolor var.bicolor forms dominant stands or hummocky meadows.Each tussock has a pachycaul habit.

Wet heath
Wet heath is restricted to the highest part of Inaccessible Island, in a narrow strip along the western edge of the plateau.It is absent from Nightingale Island.Occurring on the highest part of Inaccessible Island, it is exposed to very strong winds, and the vegetation is dense and lowgrowing (typically 200-300 mm).The formation is geographically limited, and could be considered to be a transitional form between tussock grassland and B. palmiforme heath.However, it has several characteristic species, and the large number of breeding birds concen trated in this vegetation type result in a very different proportional composition of the vegetation.

Bogs
We consider bogs as vegetated areas with impeded drainage.Two bogs with differing vegetation types are recognised.

Sphagnum bog
There are several relatively small bogs dominated by the moss Sphagnum sp. on the eastern part of the plateau on Inaccessible Island Most are located at the head of small streams.Dick's Bog in Ringeye Valley has been described in detail by Preece et al. (1986).Associated species are Histiopteris incisa var.carmichaeliana, Carex insularis, C. thouarsii, Scirpus sulcatus var.sulcatus and Spartina arundinacea.This type of bog is not found on Nightingale Island.

Scirpus sulcatus bog
Skua Bog, at West Point, Inaccessible Island, is an extensive marshy area at approximately sea level, domi nated by Scirpus sulcatus var.sulcatus with a small area of open water along the coastal edge (Preece et al. 1986) (Figure 9).Azolla filiculoides, Carex insularis, Holcus lanatus and Rumex frutescens are the only other species growing in the bog, which is surrounded by tussock grass land.A smaller patch of bog occurs behind the beach to the west of Blenden Hall, which is invaded by the alien species Mariscus congestus and Plantago major.
Small patches of Scirpus sulcatus bog are also found in watercourses on the plateau at Inaccessible Island (e.g.Molly Bog).These bogs are often invaded by Holcus lanatus, and may support some Carex insularis and C. thouarsii var.thouarsii.Many bogs on the plateau are associated with breeding white-chinned petrels (Procellaria aequinoctialis conspicillata).This species only breeds in wet areas on the plateau of Inaccessible Island, and their burrows are characterised by entrance moats.The mud and water around the burrow entrance support Hypolepis rugosula var.villoso-viscida, Callitriche christensenii and Scirpus bicolor var.bicolor.In some areas, large numbers of white-chinned petrels breed together at the upslope edge of a bog, and there is a specific pattern of bog colonization.Immediately in front of the nests is an area of open water and bare mud, and at some distance from the focus of bird disturbance this is colonized by

DISCUSSION AND CONCLUSIONS
Seven species and one variety were recorded new from Inaccessible Island, whereas two species were found to be new for Nightingale Island.These figures exclude two taxa that may prove to be new species (Apium sp. and Elaphoglossum sp.).Our observations bring the total The current survey increased the known species rich ness at the two islands by almost 10% (cf.Groves 1981).Only one new taxon was an introduced species (Conyza albida on Inaccessible Island), suggesting that the rate of transfer from the adjacent inhabited island of Tristan is relatively low.Tristan has more than 100 introduced species (Groves 1981).The low proportion of new introduced species also indicates that further collecting of the native flora is warranted, and that the number of vascular plants probably is larger than that reported here.Some taxa require systematic review, notably Nertera, Uncinia, some of the grasses (Agrostis, Calamagrostis and Deschampsia), and some of the ferns (Elaphoglossum and Asplenium).
The climate of Inaccessible and Nightingale Islands is cool temperate oceanic (Wace & Holdgate 1976).There are few meteorological observations from the islands, but

FIGURE 1 .
FIGURE 1. -A view of Inaccessible Island from the north.The island is characterised by its steep cliffs.

FIGURE
FIGURE 3 -Map of NightingaleIsland showing the major col lecting sites.(Adapted from Groves 1981).
discuss the Quaternary paleo botany of Inaccessible Island.The vegetation types of the various islands in the Tristan group are broadly similar, and we have adopted the terminology used by Wace & Holdgate (1958 most of Nightingale Island and occurs along the steep cliffs from sea level to ± 500 m on Inaccessible Island.The formation consists of large Spartina arundinacea tussocks which are up to 3.5 m tall.On drier, more exposed ridges 5. arundinacea tussock is replaced by Blechnum penna-marina heath on the west coast of Inaccessible Island.

FIGURE
FIGURE 10.-First Pond, Nightingale Island.Vegetation in this bog consists o f an outer zone domi nated by Scirpus sulcatus var.sulcatus followed by a zone of Blechnum palmiforme.The central part of the bog is domi nated by Phylica arborea.The nesting bird is a yellow-nosed albatross, Diomedea chlororhynchos.
briefly describe the status, distribution and ecology of the vascular plants recorded from Inaccessible and Nightingale Islands.All comments refer to Inaccessible Island, unless otherwise stated.Alien species are marked with asterisks, unrecorded, incorrect species/names with a dagger and the distribution within the Tristan/Gough Islands is denoted by the initial letters of island names (G = Gough, I = Inaccessible, N = Nightingale, and T = Tristan).Author abbreviations follow Stafleu & Cowan (1976-1988).The taxa are arranged alphabetical'y.the upper slopes and plateau, chiefly above 250 m.It occurs primarily in fairly sheltered microhabitats in fern bush and wet heath.It is particularly abundant between decumbent Blechnum palmiforme caudices and in moss beds among Phylica scrub.Distribution: G, I, T. Dean 832 (BOL); Roux 2122is widespread in wet heath and B. palmiforme heath, and is locally common in Phylica woodland, but is absent from the Serengeti.It also occurs in exposed conditions as a lithophyte on rock outcrops or low cliffs.In deeply shaded and sheltered conditions the fronds may be pendulous, whereas in exposed habitats they are erect.sparsely above 300 m on moist soil slopes shaded by dense stands of Ctenitis aquilina.Distribution: endemic, G, I, T. Roux 2157, 2163 (NBG).A. erectum Bory ex Willd.: 328 (1810).Fairly common at all altitudes, growing on shaded rocks or under other vegetation including Spartina tussock and fern communities, but is never dominant.Distribution: G, I, N, T. Dean 828 (BOL); Roux 2096, 2158, 2178, 2191, 2211 (NBG).A. obtusatum G. Forster var.crassum (Thouars) C. Chr.: 12 (1937).A. crassum Thouars: 33 (1808).Common at all altitudes, frequently growing on exposed cliffs.Also occurs on flat ground, in moist conditions among boulders near sea level, but is more widespread on the plateau.In Phylica woodland plants form clusters up to 1.2 m in diameter.It is apparently fairly resistant to trampling, occurring with Scirpus bicolor at albatross loafing sites. in wet heath, but also under Phylica woodland.It was found among Spartina tussocks on Nightingale Island for the first time.Distribution: endemic var.. I, N. Dean 831 (BOL); Roux 2108all altitudes, but at lower elevations it is largely restricted to watercourses and boulder fields at the base of cliffs.Abundant over much of the plateau, where plants are stunted in wet heath and Blechnum palmiforme heath compared to those at lower altitudes.It often forms extensive dominant stands under Phylica woodland, but is absent from the Serengeti.Distribution: endemic.G, I, N, T. Dean #/0(BOL); Roux 2092, 2147, 2193 (NBG).Elaphoglossoideae Elaphoglossum campvlolepium J P Roux: 234 (1991).The species is evidently restricted to higher elevations and on Inaccessible Island it is known from ± 450 m.It often grows in asso ciation with E. succisifolium in exposed or sheltered conditions.succisifolium, this species is common at all altitudes and is present in all vegetation types.It prefers more sheltered habitats than E. succisifolium.It often forms dense monospecific stands in Phylica woodland with fronds attaining a length of 400 mm.An apparently undescribed Elaphoglossum species occurs on Inacces sible Island.It is distinguished from E. laurifolium by its narrower, less robust fronds, the somewhat elevated midrib on the adaxial surface, and the stellate scales on the abaxial surface.It is patchily distributed on the plateau between 2 0 0 -4 0 0 m, where it forms large dominant stands on exposed ridges and streambanks.Few fertile fronds were found throughout the summer.Distribution: endemic, G, I, N, T. Dean 801, 875 (BOL); altitudes and present in all vegetation types.It occurs as a geophyte in deep moss in gullies, on exposed cliffs and rocks and as an epiphyte on caudices of Blechnum palmiforme.the coastal slopes, where it occurs sporadically up to 350 m, although mostly below 200 m.It is scarce in the valley above the Waterfall It is common in slightly shaded areas among Spartina tussocks and in association with Blechnum penna-marina It also grows in more exposed conditions in crevices among boulders, and occasionally on cliffs.B australe was collected for the first time at Nightingale Island.Distribution: G, I. N, T. Dean 798 (BOL); Roux 2059, 2185, 2190 (NBG).B. palmiforme (Thouars) C. Chr.: 10 (1940).Pteris palrruformis Thouars: 30 (1808).Occurs at all altitudes, and is the dominant plant on much of the plateau On the high western plateau the caudices are procumbent, forming a confused tangle (evocatively described by Carmichael 1818), whereas in Phylica woodland, where the plants are more protected, the caudices may reach a height of up to 2 m.The species is scarce on the coastal slopes, occurring in small numbers on ridges.altitudes, often forming extensive dominant stands on exposed ridges on the coastal slopes in the west.It is seldom dominant on the plateau, but is widespread, occurring at low densities in all vegetation types.Juvenile fronds are reddish, and fertile fronds are produced coastal slopes, mostly below 250 m, although a small population was found on the slump below the northwest-facing scarp at ± 400 m.It is common in tussock grassland, primarily in Blechnum penna-marina heath, often forming large stands on steep slopes and ridges.It is scarce on the northeast coast, only found at the huts near the altitudes in moist conditions.At low elevations it is restricted to deep shade among Spartina tussocks, whereas on the plateau it is more widespread.It is abundant in fern bush, forming dense monospecific stands in some areas (e.g.Harold's Plain), but is scarce in wet heath.The plants are deciduous.Distribution: endemic var., G, I, N, T. Dean 808 (BOL): the plateau and upper slopes of Inaccessible Island, but also down to sea level at Waterfall Beach.It generally grows in association with breeding birds, and is common in disturbed areas in wet heath.It is absent from the Serengeti where burrownesting birds are scarce.On the western scarp it occurs along .subsp.magellanica Fairly common on the plateau above 200 m, growing as an epiphyte on caudices of Blechnum palmiforme and.less frequently, on moist, shaded cliffs.All the Gmmmitis collections made during the expedition conform with the diagnostic features of G. magellanica var.magellanica provided by Pams (1981).It therefore appears as if G. poeppiguma (Pams 1981), which has previously been reported from Inaccessible, is incorrect.Distribution: G. I. N. T Dean SJ7(BOL); Roux 2126altitudes, in Blechnum penna-marina heath, fern bush and wet heath.Although more abundant on exposed ridges and slopes, it also occurs in partially shaded conditions under Phylica scrub.Rapidly colonizes slips on the plateau.Spores are released from midgrow behind the huts at Waterfall Beach (cf.Wace & Holdgate 1976), with no sign of seedlings despite producing cones with seeds.Distribution: I. Ryan 92 (BOL).situations than C. thouarsii at all altitudes.At sea level it is largely restricted to bogs such as Skua Bog, and on the plateau occurs along watercourses.It is, however, more widespread in wet heath.Distinguished from C. thouarsii by its triangular (cf.terete) habitats such as soil slips and around albatross nests.It is distinguished from C. thouarsii var.thouarsii by its smaller size, which may merely be a consequence of growing in drier habitats.Distribution: endemic, G, I, T. Dean 788 (BOL, NBG).var.thouarsii Widespread.Occurs in Phylica woodland at both Inaccessible and Nightingale, but is most abundant in wet heath on the plateau at Inac cessible.Many of the seed heads are completely denuded by endemic buntings.Distribution: endemic, G. I, N, T. Dean 787, 861 (BOL); Rou.x 2203 (NBG), Ryan 58 (BOL).* Mariscus congestus (Vahl) C.B. Clarke: 72 (1897).Cyperus congestus Vahl: 350 (1805).Dominant in marshy areas at Blenden Hall, although not yet found at Skua Bog.It has reached the bottom of the rope on West Road at ± 100 m .It also occurs on wet slips above the beach towards Warren's Cliff, at Salt Beach (one plant), and around the huts at Waterfall Beach.Flowers December-February.Seeds are eaten by the endemic buntings, and this may facilitate dispersal because seeds sometimes are found ad hering to feathers around the base of the bill.species, occurring throughout the islands.Two forms are found on the plateau; one tussock form with very fine leaves and small flower heads that is almost invariably associated with birddisturbed areas, and one that forms large trailing, tangled mats, charac terized by short, broad leaves and few, small-flowered heads.The latter type is particularly abundant in wet heath.At Nightingale a tussock form occurs in dominant stands, forming hummocked meadows.Distribution: endemic, G, I, N, T. Dean 795, 807, 820, 825, 859, 868, 871 (BOL); Roux 2064 (NBG); Ryan 66 (in rocky areas and soil slips in Spartina arundinacea tussock vegetation, and also forms fairly robust tussocks on the plateau.The former is common on bare ground above the beach, whereas the latter is widespread in undisturbed vegetation on the plateau.This variety has seeds twice the mass of those of var.bicolor.Scirpus moseleyanus Boeck.: 262 (1875).Distribution: endemic var., G, I, N, T. var.sulcatus Common at all elevations in open areas, along streams, and in bogs where it forms extensive monospecific stands.Seeds germinate while in the seed head.Flowers earlier at sea level; sprouting seeds were found from December at Skua Bog, but seeds only ripened on the plateau in February-March.in wet heath.Fruits are present throughout the summer.It is distinguished from the other Nertera species by its small (< 5 mm long), entire leaves.Nertera on Inaccessible, restricted to the plateau where it is patchily distributed in fem bush.Typically occurs in the shade under Blechnum palmiforme or Phylica arborea, but also occurs in the open on the flanks of Swale's Fell.Apparently fruits later than other Nertera species, with the first ripe fruits appearing in March.It is distinguished by its large (typically >10 mm long), entire, glossy dark green leaves.Groves (1981) from Inaccessible, but recorded by Wace & Dickson (1965) and Preece et al. (1986).It is common on exposed areas such as soil slips above Blenden Hall, especially the slips adjacent to the West Road and on the slump below the plateau edge north of the West Road.Isolated patches also occur at Boulder Hill and Swale'

-Map of Inaccessible Island showing the distribution of the major vegetation types. FIGURE 5.-Map of Nightingale Island showing the distribution of the major vegetation types.
N FIGURE 4. lanatus, Hydrocotyle capitata, Rumex frutescens and Scir pus sulcatus var.sulcatus are commonly found.Calystegia sepium subsp.americana and C. tuguriorum climb over Spartina tussock in some areas.

Typical Blechnum palmiforme heath is absent from Nightingale Island, although small stands of B. palmiforme occur at First and Second Ponds. FIGURE 1. -Fern bush: Blechnum palm iform e heath on the plateau. Inaccessible Island. B palmiforme and Phylica arbo- rea are dominant in this com munity. The stunted growth of the plants may be ascribed to the prevailing westerly wind. Bothalia 22,1 (1992) Blechnum palmiforme is
the dominant species and the procumbent caudices form a confused tangle with only the apical part turning upwards, bearing a crown of coriaceous fronds 200-400 mm above the ground.Several species of these ferns (e.g.
Ringeye Valley.This is a diverse community, and the following species are common: Amauropelta bergiana var.

sulcatus, Spartina arundinacea, Uncinia brevicaulis
and t/.meridensis.This is the only area where Glyceria insularis is found away from watercourses, and Cardamine glacialis, Deschampsia mejlandii and Ranunculus mauricatus occur nowhere else on Inaccessible Island.Disturbed areas in the immediate vicinity of albatross nests and petrel burrows are colonised by invasive species such as the introduced Cerastium

fontanum, Holcus lanatus, Poa annua and Rumex obtusifolius, as
well as native species such as Gnaphalium thouarsii.Southeast of Swale's Fell and in the northern part of Ringeye Valley, typical wet heath is absent, and tussock grassland merges almost directly into Blechnum palmiforme heath.However, there is a peculiar mixture of the two formations at Dune Hills, with sparse Spartina arundinacea growing in amongst B. palmiforme heath.Farther northwest, towards Molly Bog, S. arundinacea is replaced by abundant tussocks of Calamagrostis deschampsiiformis.

TABLE 1 .-Numbers of species of vascular plants on Inaccessible and Nightingale Islands. Endemic species are those entirely restricted to the Tristan-Gough group of islands, and does not include endemic varieties or subspecies Endemic Number of species
* includes two species which may be extinct (Raphanus sativus and Physalis peruviana), but excludes Centella asiatica, for which there is no collected material.number of species recorded from the islands to 98 and 43 for Inaccessible and Nightingale, respectively (Table1).Only three taxa are found on Nightingale that are absent from Inaccessible, the two species of Cotula (one endem ic and one introduced) and the endemic Atriplex plebeja.A total of 28 introduced vascular plants occur on the is lands, all spermatophytes.The proportion of alien plants is greater on Inaccessible Island (27.7%) than on Nightin gale Island (16.3%).