Notes on the Phytogeography and Flora of the Mountain Summit Plateaux of Tasmania Author(S): L

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Notes on the Phytogeography and Flora of the Mountain Summit Plateaux of Tasmania Author(s): L. S. Gibbs Source: Journal of Ecology, Vol. 8, No. 1 (Mar., 1920), pp. 1-17 Published by: British Ecological Society Stable URL: http://www.jstor.org/stable/2255210 Accessed: 26-06-2016 20:21 UTC

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This content downloaded from 163.118.172.206 on Sun, 26 Jun 2016 20:21:33 UTC All use subject to http://about.jstor.org/terms VOLUME VIII MARCH, 1920 No. 1

NOTES ON THE PHYTOGEOGRAPHY AND FLORA OF THE MOUNTAIN SUMMIT PLATEAUX OF TASMANIA

By L. S. GIBBS.

CONTENTS. PAGE INTRODUCTION 1. Geological History ...... 1 2. Physiography ...... 2 3. Meteorology ...... 3 GENERAL PLANT FORMATIONS (i) Austral-montane flora of the Mountain Summit Plateaux 4 (ii) Mixed Forest of the West Coast . 5 (iii) Eucalyptus Formation of Australian Type A. Forest ...... 7 B. Open Forest ...... 8 C. Secondary Open Forest . . . .8 DESCRIPTION OF MO-UNTAINS . . .10 (To be continued.)

INTRODUCTION. Tasmania, a comparatively small island, about 27,000 square miles in area, lies on the S.E. of the Australian continent, where it is exposed on the west coast to the full sweep of the South Pacific gales, which, unintermittently blowing from west to east, know no break in land between Tasmania and Cape Horn. The northern coast is about 184 miles from that of Victoria' and an elevation of only 180 feet would suffice for broad bridges on which one could pass dryfoot from Tasmania to the Australian mainland2 . These shallow areas point to a former land connection, confirmed by geological evidence.

1. GEOLOGICAL HISTORY. The isolation is considered to have occurred in the later quaternary period during an era of subsidence accompanied by volcanic outbursts3. A glacial period subsequently intervened, during which "Tasmania must have formed an island of about three-quarters its present area, and there existed no land connection with Australia 4." "We can assume that during that time the climate was perhaps that of the Kerguelen Islands, with no vegetation to 1 F. Noetling. "The Antiquity of Man in Tasmania." Proc. R. Soc. Tas. 1910, p. 232. 2 F. Noetling. "Entwurf einer Gliederung der Jungterziiiren und diluvialen Schichten Tasmaniens." Zentralb. f. Min. Geol. und Pal. 1909, p. 10. 3 F. Noetling. "Ant. Man. in Tas." Loc. cit. p. 246, 4 F. Noetling. Loc. cit. p. 251. Journ. of Ecology VIII 1

This content downloaded from 163.118.172.206 on Sun, 26 Jun 2016 20:21:33 UTC All use subject to http://about.jstor.org/terms 2 Mountain Summit Plateaux of Tasmania speak of but moss and low shrubs'," then "Tasmania would have had an area of 18,000 square miles, one-third of which was under ice and snow2."

2. PHYSIOGRAPHY.

It must be obvious to the most casual observer familiar with the results of volcanic activity in other parts of the globe, that the country was formerly one huge plateau formed of horizontal lava flows. The present con- figuration has been determined by the subsequent erosion of these sheets of diabase; the graphic evidence is as conclusive for other parts of the country as Graham Officer3 has already described for the country round Lake St Clair. This plateau, as already shown, was glaciated, and huge glaciers stretched down into the valleys of the present time4. Progressive sub-aerial weathering and denudation accounts for the breaking down of the superimposed strata into tier upon tier of this greenstone country, and the now isolated groups of high tablelands. The diabase, or greenstone region, extends over the whole central portion of the island, from the West Coast mountains to Ben Lomond on the east, and Mts Field, Wellington and Hartz in the south; some of the so-called mountains being simply high tablelands of large extent with flat summit plateaux, while others are worn down to mere bilateral ridges and isolated peaks. In fact the whole sculpturing of this portion of the country is remin- iscent of Iceland, with its recent horizontal lava flows and the similar effects of glacial and sub-aerial denudation. In the present-day Tasmania is distinguished by three geological regions, viz. (1) The great Central Diabase or Greenstone Plateau, commonly called the Central Lake Plateau, about 2500-3300', from which the river systems of the island radiate, is more or less surrounded by the now isolated mountain summit plateaux, from 3500-5000', with which it was formerly connected. The rivers rise in the five large lakes, whence this high tableland derives its popular name, viz. Great Lake, 3300'; Lake Echo, 2500'; Lake St Clair, 2500'; and Lakes Sorell and Crescent, 2600'. (2) The West Coast. Composed of pre-cambrian schists, gneisses, granite and allied rock types5, in rugged mountain masses, whose summits do not exceed 4500'; these are simply high tablelands weathered in tiers, like the diabase mountain summit plateaux of the central and southern regions. The western region is characterised by an exceedingly heavy rainfall of over 150 inches.

I F. Noetling. Loc. cit. p. 249. 2 F. Noetling. Loc. cit. p. 251. 3 Graham Officer. "The Geology of the Lake St Clair District." Proc. R. Soc. Tas. 1893, p. 156. 4 F. Noetling. Loc. cit. Zentrbl. Min. Geol. Pal. 1909, p. 9. 5E. C. Andrews. "Notes on the structural relations of Australasia, N. Guinea and N. Zealand." Journ. Geol. CIhtcajo, 24, 1916, p. 753.

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(3) The Lowlands and Uplands of the N. and N.E. Coasts, chiefly diluvial, forming undulating sandstone plains.

3. METEOROLOGY.

The climate is temperate in character, judged by thermometric readings alone. Taking the following stations it will be seen that the variation in temperature is not great and compares favourably with places of equivalent position in the northern hemisphere1.

Mean Yearly Locality Latitude Temperature Winter Summer range 0 , ft 0 0 0 0 Hobart 42 53 32 S. 54*41 46 8 61F95 15410 Edinburgh 55 58 N. 47 15 38 4 57 17 18 72 London 51 30 N. 50 83 39 50 62 93 23 43 Paris 48 50 N. 51F31 37 85 64 50 26 73

The rainfall varies. It is-heaviest on the West Coast, where the records for the mountain stations are: Mt Read, 165*77; Mt Lyell, 131-47; Zeehan, 122-71; Queenstown, 112-71 inches for the year 19172. For the Central Plateau, Interlaken, Oatlands and Ross on the east show 40-48, 37*32 and 29*11 inches respectively. The precipitation on the western portion of the Plateau is nearly three times that of the eastern portion3. There are apparently no records for the mountain summit plateaux, but the stations on Mt Wellington (Gap) and at the "Springs" at 2500' record 98-51 and 96*29 in. respectively, while Hobart, which lies at the foot of the mountain, shows 41*69 in. Scamander and Swansea on the sheltered and dry east coast have a total rainfall of 26*18 and 33*31 in. respectively, the latter corresponding more or less with Launceston on the north coast. Schenck4 has already emphasised that the nature of the plant covering is determined by the barometric and not the thermometric readings, for all the scattered austral lands of the sub-antarctic. He quotes Ross as being the first to observe that the character of the seas and islands geographically belonging to the south temperate zone, lies in the low summer temperature and the constant severe storms, in contrast to those of the north temperate zone with their mild climate and rich organic life. On the high tablelands and West Coast of Tasmania, winter and summer, the wind is incessantly from the N.W. to S.W. 5, with constant cyclonic disturbances, irrespective of seasons. A heavy swell always prevails round the West Coast. The constant precipitation of the storm driven clouds causes such excessive rainfall that the

1 Walsh's Tasmanian Almanac, 1918, p. 13. 2 Tas. Alm. pp. 14-15. 3 R. M. Johnston. "The Glacial Epoch of Australia." Proc. R. Soc. Tas. 1893, p. 95. 4 H. Schenck. "Vergleichende Darstellung der Pflanzengeographie der subantarktischen Inseln." Wiss. Erg. Deutsch. Tiefsee-Exp. ii. i. Jena, 1905, p. 7. 5 W. V. Legge. " Contribution to the Physiography of Tasmania." Pine, Island, Great Lake. 1902, P. 759.

1-2

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foothills and upper slopes of the ranges are clothed in a dense miixed forest, only the extreme summits being exposed. The north and north-east portion of the island, though more or less protected from the prevailing west winds of the antarctic region by the West Coast mountains and the Central Plateau, resulting in a lesser rainfall, is however exposed during the summer to the hot north winds from Australia, and the vegetation consequently approximates to the Australian type.

GENERAL PLANT FORMATIONS.

All endemic species are marked by an asterisk. The plant covering of Tasmania is of a very uniform description and can in fact be easily divided into three principal formations, the basis of these formations depending primarily on the physiography, wind incidence, rainfall and edaphic factors, or on secondary conditions of ethnographic modifica- tion. It may be classified as follows: (i) Austral-montane' flora of the mountain summit plateaux. (ii) Mixed Forest of the West Coast. (iii) Eucalyptus formation of Australian type, including 4. Forest: rich humid valleys and lower mountain slopes of south central districts. B. Open forest, with dense shrubby undergrowtlh: south-east districts. C. Secondary open forest: Lowlands and Uplands of the N. and E. coasts and the Central Lake Plateau-" grazing country." Distinctive endemic elements are limited to (i) and (ii).

(i) AUSTRAL-MONTANE FLORA OF THE MOUNTAIN SUMMIT PLATEAUX. As the number of indigenous plants found in the island is limited, so also are the members of each formation, and given the same conditions, the same plants reappear. There are no dividing ranges to isolate different species, and no great variations of temperature, latitude, longitude and altitude, which are the determining factors in the greater development of the New Zealand mountain Flora sparsely represented here. The highest altitude in Tasmania is limited to 5000' restricted to a few masses of rock, vestiges of a former uniformly level area. There are no glaciers or permanent snow, therefore alpine conditions do not prevail. In the winter months, the mountains are often under snow, which at some levels and in depressions may lie till late in the summer. During summer there are spells of hurricanes and bad weather, when the plateaux may be again snow swept, then the heavy rain makes the streams impassable and the summits are often

I Oscar Drude. Handbuch der Pflanzengeographie, Stuttgart, 1890, p. 491.

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impracticable for three or four weeks at a time. After a blizzard, massed shrubs on the summit of Mt Wellington have been buried under frozen snow, the stems and branches cased in thick ice, the heat of the sun during the day melting the snow, which freezes again at night. To such fairly continuous climatic rigours, the plants have responded by dwarfed, stunted shrubby growth, small coriaceous leaves and modified branching, or a spreading creeping habit. It seems hardly accurate to describe these plateau plants of a main altitude of 3500-4500' as alpine, as following Hooker', has so far been the case. They are no doubt the vestiges of a former dominant alpine flora, which has gradually descended to lower levels, assimi- lating new elements as the climatic, edaphic and altitudinal conditions became modified. It is significant that the major and most interesting portion of the endemic flora is entirely limited to these summit plateaux, many of the plants belonging to monotypic or o]igotypic genera not known elsewhere; in fact, the indigenous conifers, including no less than three endemic genera, are, with the exception of three species, not only limited to the mountain plateaux summits and to the Central Plateau of Tasmania, but are so systematically isolated as to point to a separate focus of development on this island. In common with the whole of the sub-antarctic region, one of the peculiar features of this plateau flora is the almost complete absence of herbaceous plants, for which the discontinuity in temperature and the broken, barren nature of the surface must be taken into account. Economically both these factors preclude any grazing possibilities, and the sheep, which are exter- minating the New Zealand alpines, are absent; but casual fires and, on the West Coast, mining are quite as effective destructive agencies in Tasmania.

(ii) MIXED FOREST OF THE WEST COAST.

This formation clothes the foothills and mountain ranges. for the length of the West Coast, round to Recherche Bay on the S.W., and extending to the Central Plateau by Lake St Clair, and in the south central country to the head waters of the Huon, Gordon, Franklin and Russell rivers as far as t-he Hartz Mountains and Mt Field. A type of forest not very rich in species, it is characterised more by denseness of growth than by height. The endemic element is significant, and as most members of this formation are included in the dwarf and low forest associations of the mountain summit plateaux, it probably originated on the higher lands. Distinguished as the Fagus forest by the earliest collectors, from the real or fancied predominance of Fagus Cunninghamii, this term can hardly be considered locally correct, as along river banks Dacrydtum Franklinii is more pronounced, whereas Athrotaxis selaginoides may be distinct on the upper slopes of the mountains, as on the sub-summit zone of Mt Read, above

1 J. D. Hooker. Bot. Ant. Voy. III. Fl. Tas. 1, p. lvi.

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Williamsford1. Such a name also suggests comparison with the true Fagus forests of Tierra del Fuego and New Zealand, in each case represented by several species. Unlike these pure beech forests2 Fagus Cunninghamii does not approximate to the northern beeches in habit, as the colloquial name " myrtle "' aptlv suggests. The only approach to pure stands seen was at Lake St Clair in 1915, where some good trees were grouped in places at the edge of the lake, and on the west bank of the Cuvier River in mixed forest, since burnt out. They did not suggest typical beech woods, but agreed better with Legge's3 description of small "groves of beeches" for the country round Lake St Clair. F. Cunninghamii in Tasmania is infected by *Cyttaria Gunnii Berkeley as is F. fusca of New Zealand by C. Purdiei Buchan., and some of the S. American by C. Darwinii Berkeley. In each case the fungus has afforded valuable food for natives 4. Of the associated trees seen on the King River, *Dacrydium Franklinii (Huon Pine) in groups or singly, drooping in youth, more spreading when mature; *Phyllocladus aspleniifolius (White or Celery Top Pine) of neat habit with dense, dark top; with *Athrotaxis selaginoides (King William Pine), generally grouped, with symmetrical oblong top and straight brown bole, are the most valuable economically, therefore rapidly being cut out wherever accessible transport can be organised. The fragrant "Sassafras," Atherosperma moschatum, with smooth stem, whorled branches and shining leaves, the latter often infused in tea; *Eucryphia Billardieri (Leatherwood), *Anopterus glandulosus (native Laurel) with handsome white racemose blossom, were abundant as trees or under-shrubs, while the graceful palm-like *Richea pandanifolia reaches through the vegetation from any and every vantage ground. As sub-staging, *Anodopetalum biglandulosum, popularly called "horizontal wood," because its limp branches, falling on the ground, send up secondary shoots from every node, forming an impenetrable mass spread over wide areas. *Telopea truncata, Drimys aromatica, Pittosporulm bicolor, the fastigate *Cenarrhenes nitida, *Acradenia Franklinii, Styphelia acerosa, almost a small tree, *Archeria disticha and Pimelea procera were in flower. Undergrowth. This was formed of the trunks of dead trees stacked on each other, covered with a luxuriant moss-hepatic growth, or huge moss-stools where the rotting stems had remained erect, out of which rose the few wand- like branches of the slender *Aristotelia pedunculata; *Archeria eriocarpa, pink, the white-flowered *Trochocarpa disticha with the young red foliage, and *Prionotes cerinthoides in fruit, spread over the moss and up the tree

I R T. Baker. Pines of Australia, Sydney, p. 304. 2 L. S. Gibbs. "Deforestation in New Zealand." Gard. Chron. April, 1909, p. 225. 3 W. V. Legge. "Highlands of Lake St Clair." Proc. R. Soc. Tas. 1887, p. 116 (with maps). a H. Schenck. Loc. cit. p. 125.

This content downloaded from 163.118.172.206 on Sun, 26 Jun 2016 20:21:33 UTC All use subject to http://about.jstor.org/terms L. S. GIBBS 7 trunks, with Polystichum coriaceum, Hymenophyllumjavanicum and H. rarum, as the commonest ferns; young plants in abundance of all the species enumerated were general. The liverworts1 on the W. Coast were in full fruiting condition in October, or the Spring, as is also the case in the North Island of New Zealand and Fiji2. After lumbering has denuded this forest of the valuable timber, large areas are leased by the Agricultural Department at a nominal price to so-called run-holders, who run cattle through it,- first burning as much as the extreme rainfall will allow. The giant stools of moss seem to offer most resistance to the fire, but are finally replaced by huge clumps of Gahnia psittacorum (Cutting grass) apparently limited in Tasmania, the periphery of its distribution3, to damp places. The Municipality of Strahan have reserved as a park a portion of this beautiful forest, where alone one can realize the way it swept down to the very edge of Macquarie Harbour, but the area should have been of larger size. For tourist effect, the banks of the King River, where traversed by the railway to Queenstown, are supposed to be reserved by the Government. Actually, however, a screen of trees is left along the railroad, behind which the cutting out of the best trees was actively proceeding at the time of my visit. As the rainfall decreases towards the N.W. so this type of forest is gradually replaced by Eucalyptus; even between Strahan and Zeehan these trees, in proportion, markedly increased.

(iii) EUCALYPTUS FORMATION.

A. Forest.

Distinguished by its serried ranks of huge boles of uniform height, only branching at the crown, the different species to the uninitiated appearing absolutely identical, this fine forest was seen in the valleys of the Tasman Peninsula, on the southern slopes of Mt Wellington, in the Huon district, and on the lower slopes of the Hartz Mountains and Mt Field. Calling at Hobart in 1909 on my way to New Zealand and Fiji, this beautiful forest was still intact on the slopes of Mt Wellington. Magnificent "swamp gums" with towering straight white boles, E. regnans; "stringy- barks," E. obliqua; "gum-top stringy barks," E. haemastoma are the most conspicuous species, under which the smaller Fagus Cunninghamii, Athero- sperma moschatum, Acacia melanoxylon, again shade Olearia argophylla (Musk), Bedfordia salicina, *Styphelia glauca etc. The streams which drain the sides of the mountain are lined with Dicksonia antarctica, the trunks of these

1 The Hepatics collected are in the hands of Mr H. Wright for determination. 2 L. S. Gibbs. "The Hepatics of New Zealand." Journ. Bot. 49, 1911, p. 261-2. 3 L. S. Gibbs. A contribution to the Phytogeography and Flora of Dutch N. W. New Guinea. London, 1917, p. 91.

This content downloaded from 163.118.172.206 on Sun, 26 Jun 2016 20:21:33 UTC All use subject to http://about.jstor.org/terms 8 Jlountain Summit Plateaux of Tasmania tree-ferns swathed in hepatics and mosses, Trmesipteris tannensis, Trichomanes venosum anid Hymenophyllum spp., as are also the prostrate old rotting stools. In 1914, just before my second visit, the whole of the S.W. slopes of the mountain to 2500' and for about five miles from the " Springs " to the Welling- ton Falls had been swept by fire, and only the dead trees, wit,h the prostrate trunks of the fallen, remained. The heavy winter rains and violent summer storm-bursts had washed the slopes clear of the humus accumulations of centuries, precluding all chance of a renewal of former conditions. Although in type and species identical with the beautiful forest of the Otway and Gippsland ranges of Victoria, in Tasmania the component trees are not so remarkable for their size; in each case fringing groves of Dicksonia antarctica cling to the streams, as Hemitelia capensis is limited to the perpen- dicular kloofs of Table Mountain above Cape Town.

B. Open Forest.

This, the predominant form of poorer country, represents the major association of the Eucalyptus formation, but seems to be now restricted to the Tasman Peninsula and the D'Entrecastreaux Channel about Southport, where so far there had been little clearing and grazing. In this forest, fine trees, the ubiquitous "Blue-gum" E. globulus prepon- derating, just shade a dense and varied undergrowth of twiggy, often spinous shrubs, 1-2 m. height, chiefly Leguminosae, Olearias, some Myrtaceae and Proteaceae, with smaller Rutaceous, Tremandra, Styphelia, Epacris and Lormatia spp. and many ground orchids, Liliaceous and allied plants. Like the forest, this association is well represented on the southern foothills of the Otway ranges, where it is equally a fast disappearing type, yielding pride of place to the prevailing monotone of the open succession.

C. Secondary Open Forest.

Given the same conditions, the same results will be seen as ini Australia. A nmonotonous, arid-looking succession to the natural open forest now covers the greater part of the island, viz. the whole of the northern portion, north- eastern, and the Central Lake Plateau. Where clearing and sheep runs go hand in hand, combined with lighter rainfall, poor soil, excessive clearing and burning for grazing, conditions are gradually established which can only maintain an open savannah, called grazing country, as a succession to the open forest. The trees, barely adjacent, where they are of some size, shade a light sub-staging of taller shrubs like Bursarta spinosa, various Acacias etc., and wiry grasses, dotted in their season by orchids and other nonbulbous mono- cotyledons and herbaceous plants, chiefly composites, few or many of the small shrubs of the open forest remaining, according to the length of time the

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land has been under stock and the extent of burning; finally only those per- sist whose spinous leaves or aggressively woody habit, with no leaves to speak of, successfully resist stock. The Eucalyptus formation is purely Australian in type, and only dominant where conditions, natural or otherwise, approxinmate to those of that continent. As the post-glacial uplift, with subsequent denudation, increased the area of the more sheltered portion on the N. and N.E., a gradual invasion no doubt became possible, climatic and edaphic factors proving inimical to the much older austral-montane element of the highlands. In the case of Krakatau1, recent investigations have proved that first currents round coasts, then winds, are the agents in the colonisation of plants, and the former have no doubt played a considerable role, the coast plants being not only identical with the Australian, but some common to New Zea- land, South America or South Africa. Drift results over the warm waters of the dividing straits must be appreciable where so short a distance has to be taken into account, with possibilities in the transport of whole plants, as under primary conditions on the Otway ranges the forest plants in places dip into the sea without an intervening strand or beach flora. The prevalence of Australian plants of the Myrtaceae, Proteaceae etc., with persistent hard woody capsules, would also favour water transport, though the minute or winged seeds on dehiscence are equally adapted for wind dispersal. The hot summer north wind has been no doubt the most potent factor in this gradual invasion, as the numerous members of Orchidaceae and Com- positae show. Victoria, the nearest, also the coldest part of the Australian continent, has contributed most of the comparatively few genera and species (taking the Australian flora as a whole) common to Tasmania, of which these again must represent the hardiest members. Comparison of the first collections made by J. R. Forster and his son George, who accompanied Captain Cook in the "Adventure" when she visited Adventure Bay in February 17732, with the splendid results of the early British and French expeditions and the more intensive work of Hooker, Gunn, Milligan, Archer, etc., shows that from the beginning of the nineteenth century there has been no notable addition to the Australian element in Tasmania, as might have been expected from the advent of the white man and subsequent constant interchange of communications. Many boreal elements, however, have successfully established themselves3, in many cases displacing the Australian. The comparatively recent status of the Eucalyptus formation in Tasmania is proved by the fact that, in comparison with the mountain summit plateaux

1 H. Schenck. Loc. cit. p. 67. 2 J. D. Hooker. Botany of the Antarctic Voyage. III. Flora of Tamania, 1, p. cxiii. 3 Cf. L. Rodway. The Tasmanian Flora. Hobart, 1903.

This content downloaded from 163.118.172.206 on Sun, 26 Jun 2016 20:21:33 UTC All use subject to http://about.jstor.org/terms 10 Mountain Summit Plateaux of Tasmania and the West Coast floras, it does not include a single endemic genus in its area, and even the few plants found on the mainland show no great specific differentiation. Taking the genera best represented, the numerous members of the Orchid- aceae show only four indigenous species, all of close affinity to their Australian congeners; in Leguminosae, of the many widely-spread Papilionatae listed by Rodwayl only two species, i.e. Pultenaea diffusa and P. selaginoides, and of the many Acacias only A. Richeana are indigenous. In Eucalyptus five species are cited as Tasmanian and of these the two which show distinct habit, E. coccifera and E. vernicosa, are found on summit plateaux, hence their specific differentiation may be attributed to successful resistance to adverse climatic conditions, so much so that the former, where the original plant covering is destroyed by burning, seems to form the succession association. The exotic nature of this formation may be further judged by the fact that standing forests have often been killed by severe frost, of which I saw an example at Tyenna at 500', while Officer2 described "the Nive Plains covered with dead and fallen trees, the result of a severe frost 50 or 60 years ago," and Legge3 also speaks of the "gaunt sentinels, frost killed gums, which so often mar the beauty of the country," both examples occurring on the Central Plateau at about 2500'.

DESCRIPTION OF MOUNTAINS.

The greenstone mountains flank the Central Lake Plateau of which in post-tertiary times they formed one whole. Now remaining, as isolated tablelands of no great elevation, their most striking features are the uniform height, basaltic structure and great extent of their flat summit plateaux, where the many streams which radiate from the surface have their sources in various mountain lakes and tarns. The highest points are cones of broken stones or longer ridges, formed by the unequal weathering of the greenstone columns. These remains of the latest lava flow, in their highest points do not exceed 5000', and no doubt mark the original altitude of the former general plateau. To the north-east lies Ben Lomond, 5000', succeeded by the Western Mountains-4500', Ironstone-4700', and Cradle Mountains-5000', the latter of unusually rugged outline. On the mountains of the West Coast, the main masses of conglomerates and schists have weathered on the same lines of flat summit plateaux of large extent, the highest about 4500'. On the south-west by Lake St Clair lie the Eldon-4800', and Ducane ranges, Mount Olympus-4700', King William's Mts-4400'. The fine mass of Mt Field East-4200', and West with Mt Humboldt-4700', about 30 miles in extent, dominates in the south central region. Mt Wellington, the

Cf. L. Rodway. Loc. cit. pp. 30-38. 2 Graham Officer. Loc. cit. p. 155. 3 W. V. Legge. "Lake St Clair." Loc. cit. p. 114.

This content downloaded from 163.118.172.206 on Sun, 26 Jun 2016 20:21:33 UTC All use subject to http://about.jstor.org/terms L. S. GIBBS 11 best known of all, as it is the most accessible, 4200' in height and approxi- mating in extent, is situated in the south-east. South of the Huon River lie the Hartz Mts, the general level of 4100' rising to 4300' in the case of one or two peaks, which connect with the, from a distance, apparently isolated cones of La Perouse-3800' and Adamson's Peak-4000', on the south and east respectively. No surveys have so far been made of these high tablelands, so that it is not possible to give their actual extent, or to refer in any but general terms to the smaller cones, minor ridges or numerous lakes which dot their surface, many of which are still unnamed. The altitudes also are only approximate, as the official heights of the mountains are from sea-level to the highest point, and the summit plateaux, having, no economic value, are not taken into account, no matter how considerable in area. As these tablelands, from both a botanical and scenic point of view; are the most interesting part of the country and unique in the various points of interest they offer, an attempt has been made to describe those visited in some detail.

MARIA ISLAND.

Situated parallel to the east coast, this interesting island has weathered down to a more or less bilateral ridge, Mount Maria, the highest point, towards the centre of the summit plateau, being 2300', while huge diabase columns, known as the Bishop and Clerk, stand up on the north-eastern point, where the plateau weathers sheer into the sea. At the base on the coast to the N.E. is a well-known exposure of permo- carboniferous mudstonel, on which the basalt lies. Casts of shells, sponges, etc. of remote eras can be knocked off the rock as it dips into the sea where now Rhagodia Billardieri, Tetragonta implexicoma and Mesembryanthemum australe grow over and between the boulders. Above the rocks, dotted on the open coast side, small trees of Casuarina stricta and the bushy Myoporum insulare merge on the western slopes, which have weathered into a gradual incline, into open Eucalyptus succession, the trees increasing in size towards the summit. Scattered under the Eucalyptus; Styphelia humifusa, in grazed-cushions, the spreading S. strigosa, the erect, about 1 m. high *Pimelea nivea, Olearia ramulosa, Cassinil'a aculeata with Cymbonotus Lawsonianus, a tufted perennial, were in flower in September. The Eucalyptus trees ran out on to an open subsummit zone of broken, barren greenstone, succeeded by the narrow summit plateau, covered with a dense growth of Atheroperma, Drimys, Pittosporum bicolor, *Styphelia glauca, the candelabra branched *Richea dracophylla, smaller but very like the handsome Dracophyllum Traversii of New Zealand highlands, Notelaea 1 R. M. Johnston. "Further notes on the 'Permo-carboniferous fossil cliffs' at Darlington, Maria Island." Proc. R. Soc. Tas. 1900-1901, pp. 11-20.

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bqustrina, *Olearia obcordata, Bedfordia salicina, interspersed with the smaller shrubs Correa speciosa, Pomaderris apetala, *Pimelea nivea and Coprosma nitida with Phymatodes Billardieri and Lycopodium varium between stones. On the eastern or sea face of the summit plateau, the titanic columns are wedged apart, so much so that it is often necessary to jump from one to the other; their smooth faces, magnificent and sheer, drop to the sea 2000' below, fringed by a green line of vegetation, continued vertically by the -starlike heads of massed tree ferns lining the interstitial joints of the diabase columns for some distance upwards. Only complete protection from the drying summer north wind, combined with the constant moisture draining through the joints of the diabase, could account for the unexpected presence of these plants, most unusual in such immediate proximity to the sea.

MOUNT WELLINGTON.

Mt Wellington is not only the most easterly of the large summit plateaux but is also the most weathered, some low rock masses alone remaining of the former elevation. The present plateau is breaking away in places, notably at the "Organ Pipes," on the southern face, where at 2500' the exposed diabase wall results in a sub-summit zone with *Telopea truncata, *Richea dracophyllum, *Styphelia glauca, etc. luxuriating under open Eucalyptus, plateau plants like *Pimelea sericea and the pretty mauve Veronica nivea, etc. being carried down with the disintegrating greenstone. As this part of the mountain belongs to the Municipality of Hobart, which keeps up a mountain hostelry at the "Springs," 2500', natural conditions, although every effort is made to respect them, have been considerably modified, the result of fires and provision of ready access to the summit plateau. The "Springs " zone round the mountain limits the interesting small tree, *Senecio Centropappus, only known from Mt Wellington and the Dromedary, whose peculiar fastigiate form and delicate green foliage, splashed with yellow when in flower, make it so conspicuous a-mongst the sage green of the prevailing Eucalyptus. Well-developed mountain shrubberies cover the summit plateau rocks if there is shelter. Otherwise barren and bare, rocky flats and marshy areas alternate on the endless level surface, whence Mr Rodway informed me, more delicate plants like Podocarpu,s alpinus and *Microcachrys tetragona, formerly abundant, have disappeared.

THE DROMEDARY.

This long, isolated hill, over 3200', forms a conspicuous landmark from Hobart as it skirts the Defwent near New Norfolk, worn to a narrow bilateral

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ridge which still shows the greenstone crest. The slopes to the summit are all secondary open Eucalyptus under which Caladenia carnea, C. latifolia, Ranun- culus lappaceus var. scapigeru,s, R. rivularis, Cardamine hirsuta, Stellar'ia flaccida, Sagina procumbens, Linum marginale, Myosotis australis, Brachycome decipiens, Helichrysum scorpioides, Senecio australis were collected on the way up. On the greenstone summit a small vestigial shrubbery showed *Telopea truncata in fruit, *Spyridiumtn ulicinum, Coprosma hirtella, *Helichrysum antennarium in bud, and the handsome * Veroni,caformosa in flower in Decem- ber. A few hundred feet below *Senecio Centropappus grew in a small marsh under Eucalyptus, where a new Morchella *M. tasmanica was also found, with the grass Hierochloe redolens.

MOUNT FIELD (East and West).

Mount Field, East and West, is more or less quadrilateral in shape, cut out by the plains of the Derwent and the Dee on the north, the Russell Valley on the east and the Florentine Valley to the south-west. The summit slopes from west to east, the highest parts, Mt Field West with Mt Humboldt, being on the western side. From its south central position the flora of Mt Field is interesting, as it is the eastern limit of many west and south-west types, such as *Pherosphaera Hookeriana, *Athrotaxis selaginoides and *A. cupressoides, *Fagus Gunnii, *Richea pandanifolia, etc. Mount Field West. The western portion of the mountain plateau is much more broken in outline and of greater altitude, therefore more varied in its plant associations and more beautiful in scenery than the eastern part. The highest portion remaining, an irregular arete like a broken comb, forms the summit ridge running from north to souith-4700', poised on piles of shattered diabase in indescribable confusion, which weathers down the western slopes. From this ridge to the S.W. the long eminence of Mt Humboldt divaricates at an oblique angle from the parent mass, terminating in a magnificent bluff, rising sheer from the Florentine Valley. The summit plateau is gently rounded in outline, a few tors showing on its even surface of plant mosaics; but the eastern slopes, simply stonefields, face the similar western slopes of Mt Field West. The highest points of the summit arete alternate with small saddles, where some humus can accumulate, marked by the reddish foliage and pink flowers of Epilobium confertifolium, the bright orange yellow with reddish peduncles of Senecio pectinatus and *Raoulia Planchoni which, with its spreading rosettes of white woolly leaves, replaces the Edelweiss for the Tasmanian mountains as Helichrysum grandiceps for the New Zealand Alps. Fine examples of mountain shrubberies also spread over these saddles or breaks in the summit arete, the collecting areas of streams which, on the eastern side, drain through the stones encumbering the face of the ridge to the summit

This content downloaded from 163.118.172.206 on Sun, 26 Jun 2016 20:21:33 UTC All use subject to http://about.jstor.org/terms 14 lountain Summit Plateaux of Tasmttania plateau spreading at 3500' below. As the streams materialise, fanshaped areas or sheltered angles are covered with thickets of the dwarf conifer, *Diselma Archer', about 150 m. high, to be succeeded at somewhat lower levels by the denser, much branched, almost impenetrable growth of *Fagus Gunnii, about 2 m. high. The infant Broad River, however, breaks from the arete on its downward course in several tiers of small hanging lakelets connected by waterfalls, then spreads over the charmingly wooded summit plateau, all open park-like dwarf forest, through a boulder strewn series of shallow lakes. Increasing in volume the torrent cuts through the slopes of the plateau as they dip down to Lake Webster, whence it emerges at 3000', to spread over marshy ground down the valley which, bisecting the plateau, divides Mt Field East and West. The western slopes of this valley are clothed in the low mountain forest, enfolding several lovely lakes. The dry eastern slopes only bear small Euca- lyptus scrub, through which, over a lower parallel ridge, that part of the summit plateau called Mt Field East, approximately 3500', is reached. The highest point is a more or less double cone of broken greenstone, rising to 400' on the north-east. Several minor cones and parallel small ridges of broken greenstone, covered with mixed shrubberies or small Eucalyptus scrub, occur. The largest lake, Lake Fenton, is a beautiful sheet of water, lying approximately east to west, some three miles long, surrounded by a most interesting mixed shrubbery association. Large boggy areas mnark peat deposits, where streams and pools fringed with the dwarf conifer *Pherosphaera Hookeriana and other plants peculiar to this association stretch across the plateau. The northern slopes of Mt Field East are so well wooded that there is actually no sub-summit zone, the forest merging imnperceptibly with the mountain shrubbery of the summit plateau on the crest. Below Lake Fenton, on the east, the summit flora insensibly thins out on to the usual barren sub-summit stonefield, extending for a couple of hundred feet or more, where loose stones constantly shifting are as constantly renewed from above. On the lower side of the stonefield the rich mixed forest of the upper slopes of the mountain again insensibly begins. This most beautiful forest growth, *Phyllocladus, F. Cunninghamii, Atherosperma, Drimys, lower down associated with giant Swamp Gums, shades *Anopterus, *Anodopetalum, Olearia argophylla, etc., aind masses of tree ferns, here not limited to the streams, Tmesi- pterts tannensis, filmy ferns, mosses and liverworts draping their stems, which, rising from moss-draped and rotting prostrate trunks, form part of this veritable primary forest. Just before I left Tasmania in 1914, the eastern portion of this area, the most interesting of all the Tasmanian mountain tablelands, from its varied

This content downloaded from 163.118.172.206 on Sun, 26 Jun 2016 20:21:33 UTC All use subject to http://about.jstor.org/terms L. S. GIBBS 15 physiography and the blending of western and eastern types of vegetation, was reserved as a national park, comprising about 27,000 acres.

MOUNT OLYMPUS.

The flat summit and buttressed face of this mountain is a very conspicuous feature from the head of Lake St Clair. More or less bilateral in form, owing to the excessive weathering of the diabase summit plateau, the northern- slopes rise gradually from the very -edge of the lake, clothed to the summit crest in mixed forest. On the southern face, the eastern end may be described as a fall of titanic columns, still intact on the summit, poised one on the other, but smashed beyond recognition at the base, where a small saddle connects with a now detached peak, on which just a few upstanding columns remain. The summit plateau is described by Legge' as measuring three-quarters of a mile by one-third. Along the south side, the columnar wall of diabase is exposed to about 500' in depth, and weathering back so rapidly that buttresses of broken columns stand out against the main face forming little gullies or couloirs, on whose steep, sheltered floors, cool and humid from the constant drip through the rock fissures, small colonies of little herbaceous plants enjoy ideal shelter under the only approach to boreal montane conditions seen on these barren summit plateaux, but which, I have been told, are also to be found on Cradle Mountain. Below these gullies spread stonefields for another 500', resulting in a sub-summit zone of mountain shrubberies which clothe the extensive slopes of detritus, extend across the saddle, connecting the small peak with the main mass where Podocarpus alpinus, *Diselma, *Fagus Gunni, *Bellendena montana, *Cyathodes straminea var. macrantha with creamy flowers and red berries, *Olearia persoonioides var. alpina and *0. pinifolia were general. These shrubberies are succeeded by the even line marking the carboniferous sandstone on which the diabase rests2 of secondary open Eucalyptus, which clothes the southern slopes to the "button-grass" plains of the Cuvier River below at 2900'. Dotted under these open trees Libertia pulchella, Veronica calycina and Senecio pectinatus var. pleiocephalus with *Tetracarpaea, *Olearia persoonioides and 0. glandulosa were noted.

MOUNT READ.

Situated on the West Coast this mountain forms a huge plateau of irregular outline, on which rise the highest points, Mt Dundas, 3900', on the east, a wooded cone, the upper half alone above tree level; Moore's Pimple, of which just the rounded crest is exposed, carrying a greyish looking rosette plant mosaic, on which the white flowers of Erigeron pappochromus at ? 3 cm., and 1 W. V. Legge. "Lake St Clair." Proc. R. Soc. Tas. 1886, p. 125. 2 Graham Officer. Loc. cit p. 152.

This content downloaded from 163.118.172.206 on Sun, 26 Jun 2016 20:21:33 UTC All use subject to http://about.jstor.org/terms 16 Mountain Summit Plateaux of Tasmania the pink ones of *Helichrysum pumilum at 6 cm., formed alternating colour levels. Mt Read proper is a long rising buttress, the plane surface all level plant mosaics, crowned at the western extremity by a couple of tors of exposed rock, 3900', whence the broad view is bounded on the immediate north by Mt Murchison and the narrow dividing valley; on the east by the white barren Queenstown ranges, of which the vegetation has succumbed to the sulphur fumes from the Mt Lyell mines, while on the west parallel ranges of wooded foothills roll to the ocean. The rest of the plateau is forest clad, chiefly low mountain forest, a pleasing change to the endless toilsome stonefields of the greenstone country. Growing on peat, the trees *Athrotaxis selagivoides and *A. cupressoides dominant, with Atherosperma, *Telopea, *Richea pandanifolia, etc., attain a height of 3 to 4 m. but are too close together for much undergrowth. Several lakes lie embedded, at different levels, in the prevailing greenery. The largest, Lake Johnson, 3500', is surrounded by the forest to the water's edge, where a group of *Richea pandanifolia about 3 m. high, suggests huge altar candelabra, from the stiff and peculiar branching in one plane. On the Williamsford side, to the very crest of the plateau, the mines had destroyed all this forest, leaving gnarled and bleached trunks, embedded in bleached peat, where Bauera rubioides spread widely. Further to the east, on hard clay, an interesting impenetrable dwarf forest, composed of intermixed trees and shrubs, all the same level, ? 2 m. high, densely clothed the crest, but the greater part had been burnt off. It was only on the summit and flanks of the mountain as they sloped towards Dundas, far beyond the radius of the mines, that the rich West Coast mixed forest was seen in its pristine state.

HARTZ MOUNTAINS.

The Hartz "Massiv" forms a rough parallelogram, of huge area, of which the northern slopes are bounded by the Huon River, while the eastern extend down the D'Entrecastreaux Channel to Adamson's Peak on the south, with La Perouse and the Pilton River to the west. Eucalyptus forest clothes the lower northern and eastern slopes, several lumber companies being at work on the Huon side. Above their operations the smaller trees of the mixed forest gradually predominate with *Eucryphia Billardieri especially abundant, which in February was a snowy mass of blossom. Above the Majendie Plains, 2000', where the *Eucryphia, in shrub form, was again conspicuous with tangled masses of the ubiquitous Bauera, the beautiful *Prionotes cerinthiodes was in profusion of flower, numberless branches spreading through the moss-swathed trunks of the trees up to 10 in., all tipped with the lovely pendant red-pink bells, a very screen of colour. *Trochocarpa Gunnii, about 3 in., with small white flowers and mauve frait,

This content downloaded from 163.118.172.206 on Sun, 26 Jun 2016 20:21:33 UTC All use subject to http://about.jstor.org/terms L. S. GIBBS 17 with *Anodopetalum and Gaultheria hispida were also abundant as under shrubs, from 2-3000'. On the crest of the plateau everything had been burnt out, including the Government hut, the tents which replaced it being pitched on burnt wood and ashes. Some distance away a couple of lakelets set in open dwarf forest, which had escaped the flames, duplicated the charm of the summit plateau of Mt Field West. The charred forms of *Athrotaxis selaginoides and *Richea pandanifolia showed that open dwarf forest had also generally prevailed over the plateau, which with several minor rock masses had been swept clear. The highest points, the Hartz Peak with the fine Lake Hartz at its base and the Pinnacle, are both pyramidal masses of broken rock, about 500' high; the Great Lake, bedded in cliffs and what remained of the forest, lies at the foot of the latter and is quite the most beautiful of the many lakes which form such a striking feature of the Hartz summit plateau. During the short time spent on this mountain, the atmosphere was so thick with smoke from the many forest fires raging throughout the surrounding country, that it was not only impossible to get any view, but it was difficult to see for any distance on the summit plateau itself.

(To be continued.)

journal of Ecology VIII 2

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