Art. XXV.—Plants naturalised in the County of Ashburton.

Transactions and Proceedings of the Royal Society of New Zealand, Volume 36, 1903, Page 203

Art. XXV.—Plants naturalised in the County of Ashburton. By W. W. Smith. [Read before the Philosophical Institute of Canterbury, 4th November, 1903.] It is now over thirty-one years since the late Mr. J. F. Armstrong, Curator of the Botanical Gardens, Christchurch, contributed the first paper to this Institute* Trans. N.Z. Inst., vol. v., 284. on the naturalised plants of the then Province of Canterbury. The list attached to his paper enumerated 171 species of naturalised plants observed by Mr. Armstrong in the neighbourhood of Christchurch. “This,” he-wrote, “is certainly very remarkable when we consider that twenty years ago few or none of these plants were known in the province.” In deploring the rapid extinction of many species of native plants, he also remarked that “the indigenous flora seems to have arrived at a period of its existence when it has no longer strength to maintain its own against the invading races.” During the intervening thirty-one years since Mr. Armstrong's paper was published the number of species of naturalised plants has vastly increased, while their phenomenally rapid dispersion, and, in many cases, aggressiveness, has proved a serious menace to practical and profitable farming in Canterbury and in many other extensive farming-areas in New Zealand. The settlement of the County of Ashburton began in 1851, when a number of sheep stations or runs were let by the Canterbury Provincial Council to gentlemen some of whom are now honoured names in the history of the province. The Ashburton County extends from the Rakaia to the Rangitata River, and from the sea-shore on the east coast westward to the dividing-range which is also the eastward boundary of the County of Westland. The flora of the whole county was then in all its native beauty and splendour. Extensive areas of magnificent primeval bush existed at Alford Forest and Springburn, and at Peel Forest, on the south bank of the Rangitata River. After twenty-five years of great activity in the sawmilling industry these richly timbered forests are now

almost “cut out.” Their sites, which will remain for a few years more or lees strewn with decaying stumps and trunks, form valuable pagtoral lands, on which all introduced fodder and other plants generally grow luxuriantly. The broad Canterbury Plains were “billowy bays of grass,” clothed with dense tussocks comprising several species of Poa (chiefly Poa australis), with extensive groups of the palm-lily (Cordyline australis) and Discaria toumatou, extending from the seashore to the slopes of the fore ranges. When the fierce north-wester blew across the plains the successive gusts produced the wave-like motions of the dense and close-growing tussocks, akin to those observed by “Australian Felix” on the grassy plains of Victoria. In the hot sunshine the tussocks absorbed and retained a great amount of heat, which, when the north-wester leached through them, produced, especially during the night, the hotter wind experienced by the early settlers domiciled on the lower half of the Canterbury Plains. Amongst the tussocks flourished many species of interesting native plants, most of which have now almost vanished from the plains. On the swampy land extensive areas of Phormium tenax, with numerous species of aquatic and sub-aquatic plants, grew luxuriantly. The draining of the extensive swamps—a work of great colonial enterprise—and the subsequent depasturing of farm stock thereon, has almost completed the annihilation of this class of native plants on the plains. The phenomenally rapid dispersion and naturalisation of numerous species of exotic plants in New Zealand, and the equally rapid disappearance of many species of native plants from their habitats, during the half-century of British colonisation will ever remain a subject of great interest to botanists. Mr. Armstrong's remarks in re the “indigenous flora having arrived at a period of its existence when it had no longer strength to maintain its own against the invading races “are very suggestive. Although we know that the native flora possess equally perfect methods of fertilisation in most species to those invading plants that have supplanted it in many large areas, its disappearance must be due to other causes at present imperfectly known. In almost every district, especially on the poorer lands, that remained for many years un-ploughed and almost untouched by stock, the displacement of the native plants by more hardy alien species proceeded apace. The conquest of the New Zealand flora by the northern invaders is due in some measure to their greater development “in the most extensive land-area of the globe, where competition has long been most severe and long continued,”** “Island Life,” p. 511. which

has fitted them to supplant the less vigorous antipodean, plants in a soil and climate perfectly adapted to their habits. With few exceptions the indigenous plants of New Zealand never attained the development necessary to fit them in the struggle with the strongly developed European plants. On the deeper and richer land of the plains, where the close-growing tussocks (Poa australis) grew high and vigorous, they more than any other class of plants prevented the dispersal and growth of introduced species. The annual practice of burning the extensive sheep-runs to promote fresh growth of the tussocks, and the subsequent Bowing of the burned areas by scattering weed-infested seed broadcast over them, will explain the occurrence of many species of exotic plants naturalised on the upland country in the early years of settlement. With so much weed-infested seed sown on the virgin soil, and considering the lack of proper tillage the land received; we should not be surprised at the presence in the colony of so many species of exotic plants and plant-parasites, interesting, though they are to the botanist and zoologist. We also know that much valuable land was purchased and farmed in the early days of Canterbury by many quite inexperienced men, whose lack of knowledge of plants and indifferent style of farming were the chief causes of the rapid spread of exotic plants now naturalised in the county and elsewhere. Many species flourish in imperfectly tilled land where many valuable economic plants and cereal crops could make little growth. Unlike the river-beds of Britain, the broad, warm, sandy, and silty flats of the glacier and other rivers crossing the Canterbury Plains provide more congenial conditions and sites for the growth of many representatives of the Scandinavian flora, where they frequently attain abnormal dimensions. A European botanist would be charmed to view the luxuriance and beauty of many species of British plants naturalised in New Zealand. When I visited the lower gorge of the Rakaia River in February, 1901, the more swampy parts were ablaze with the flowers of large masses of Erytkrœa centaurium, Prunella vulgaris, Mimulus moschœtus, Vicia tetrasperma, ænothera biennis, Geranium. molle, Galium aparine, Bellis perennis, Crepis virens, Bartsia viscosa, Plantago lanceolata, Trifolium pratense, and T. repens. I had not previously observed these plants display such great vigour nor attain such perfection of growth. The drier flats were also ablaze as far as the eye could see with the orange-coloured flowers of Hypochaeris radicata. On the small shingle-fans at the months of the numerous gullies opening into the Rakaia Valley Carduus lanceolatus grew in extensive masses, so high and strong as to be quite impassable in some places on horse-

back. This thistle is not now so aggressive on newly broken-up land in the county as formerly.** “Plant Acclimatisation” (G. M. Thomson), Trans. N.Z. Inst, vol. xxx., p. 313. Every year, daring our frequent botanical and entomological excursions, we discover alien species of plants occurring or observed for the first time in the country. It is noteworthy how isolated and strictly local some species are, and remain almost stationary, while others multiply and disperse over large areas within a few years. Some recent introductions or new arrivals in this district have increased and spread at a remarkably rapid ratio compared to many other species which were earlier comers. On the 10th January, 1899, we discovered the first specimens of Polygonum lapathifolium met with in the county. Since that date it has spread up the river, and is now annually plentiful, especially on the more silty flats. Seeing that this species spread up along the river, its fine seeds were probably carried in the plumage and adhering to the feet of the numerous sea-birds nesting on the river-flats during the summer and autumn months. On the 20fch April, 1900, my late son, Walter Valentine, discovered a few flowering plants of Stachys annua. This species is mentioned by Bentham as having been only once found in a field in Kent, England, which had been sown with seed obtained from abroad. I submitted fresh specimens of-the plant to Mr. G. M. Thomson, Mr. T. F. Cheeseman, and Mr. J. B. Armstrong, and these botanists referred to its naturalisation on the Canterbury Plains of New Zealand as an interesting fact in the artificial distribution of plants. The species is very rare, and occurs in one locality only, where I found five plants in bloom in April last. For many years it has been the custom of a number of residents of Ashburton to cart garden - rubbish, including offcast plants and dried seed-bearing stems of plants, and deposit them on the open river-bed. From this source arose several species of plants now abundantly naturalised on the river-flats. I have also observed new-comers appear on the sites where straw and hay had been deposited that had been imported in packing-cases. These were plants that generally compose some of the undergrowth of English cornfields and the chief vegetation of English meadows. They comprised Carduus lanceolatus, Capsella bursa-pastoris, Papaver rhœas, Lepidium ruderale, Silene inflata, Senecio vulgaris, Chrysanthemum segetum, Scnchus arvensis, Polygonum, aviculare, Lolium perenne, Bromus mollis, Cynosurus cristatus, Holcus mollis, and Avena fatua. The latter plant has proved a great nuisance in fields of oats for many years past.

From numerous inquiries instituted among the early settlers I have ascertained that every crop they sowed, be it cereal or fodder, new plants appeared on their farms. Some species would grow vigorously for a few years, and in a few more years they would decrease and disappear. It is generally difficult or Impossible, from the vague descriptions the old settlers give of these plants, to identify them accurately. But probably they remained so long as the rich .virgin soil retained certain plant-food necessary to sustain them, and when the land became impoverished by repeated and unscrupulous cropping without restoring the exhausted elements of the soil they were replaced by more vigorous species better adapted to the changed conditions. Nine years ago Scandix pecten-veneris was very abundant and intrusive, and covered acres of good land in some localities; but it is now comparatively rare. Many other species of exotic plants have also become less numerous within the same period. Warm seasons or continuous periods of dry, warm weather are more favourable to the development of some introduced plants than to others. During the drought and hot weather experienced on the Canterbury Plains in the years 1895–97 Solanum nigrum, Datura stramonium, and Atropa belladonna became very abundant and aggressive on rich swampy lands and along the banks of water-races in several districts in the county. These dry years were succeeded by a wet and chilly period lasting to the present time, and these plants have consequently become rare. It would have been regrettable if these heat-loving but dangerous plants had become numerous in this extensive farming district. My observations on many species of naturalised plants during the last fifteen years has convinced me that their comparative habits in all seasons is a safe guide in tracing the source of their original home. It may be of interest to botanists of the future to give brief notes on the condition of the naturalised flora of the county at the beginning of the twentieth century. Of the 368 species included in the following list—specimens of all having been collected in the county—95 per cent, belong to the Scandinavian flora; Australia is represented by 3 species, North Africa 1, South Africa 1, Asia 3, South America 3, and North America by 10 species. The three Australian species are well dispersed over the hilly region of the county. Vittadinia australis and Acœna ovina are abundant on the hills and in the warmer inland valleys. The latter grows vigorously, and is becoming a great nuisance to sheep-owners by its burrs or seed-pods entangling in the wool. Cotula australis inhabits the warm valleys of the Gawler Downs, on the upper Hinds River. The North African Cytisus albidus constituted for a de-

cade the chief undergrowth of the belt of trees extending along the railway-line for a considerable distance between Ashburton and Chertsey. Small areas of the white broom exist at present on the banks of the Ashburbon River seawards of the town. The South African Hibiscus trionum I have thrice found in different localities, but it is nowhere numerous. The Asiatic representatives include Bidens pilosa, Nicandra physaloides, and Triticum sativum. The two former were first discovered by Mr. Herring on the Alford Estate. The latter occurs in several localities. The South American natives, Oxalis rosea, Sisyrinchium, striatum, and Solanum tuberosum, occur on the river-bed as garden escapes. The North American species, Barbarea prœcox, Limnanthus douglasii, Lupinus arboreus, Callomia coccinea, Mimulus luteus, M. moschœtus, ænothera stricta, æ. biennis, Ribes sanguinea, and Pinus insignis, are widely distributed over the county. Mimulus luteus grows luxuriantly in many creeks and swamps, while M. moschœtus, the favourite musk, flourishes in large masses on the moist sandy and swampy flats. The two species of ænothera are abundant on the Rakaia River flats, and annually produce a great display of their lemon-coloured flowers, which may be seen in passing over the river in the railway-train during the summer months. The seeds falling from the ripe cones of Pinus insignis grow freely, and they have grown into dense masses in some of the older plantations. The seed of Ribes sanguinea is carried by birds, and germinates from their excreta under trees where the birds roost. With the exception of Pinus insignis, the other species in this list are probably descendants from garden escapes many years ago. The list of British and European species naturalised in the county include all the more valuable pasture-plants, comprising many grasses and clovers now forming the chief pastoral vegetation of the plains and up to several thousand feet on the subalpine ranges. In addition to many objectionable and injurious plants, they grow freely among the tussocks and snow-grasses (Danthonia) on the upland country. This class of mixed vegetation has added greatly to the value of pastoral runs during the last fifteen years, by enabling the owners to depasture larger flocks on them. Twenty years ago the common spear thistle (Carduus lanceolatus) invaded the hilly region of the county and caused great annoyance and loss to flock-owners, but it gradually decreased and became much leas aggressive. Unquestionably many species of naturalised plants occurring plentifully all over the county were early introductions.

Hypochœris radicata spread with great rapidity, and hore-hound (Marrubium vulgare) became established in large masses on every hill, knoll, and sunny slope where the flocks of sheep camped for the night, and around sheep farms and sheds where the flocks are shorn annually. Its prickly capsules are adapted for clinging to the wool of sheep and the fur of hares and rabbits—all having thus assisted to distribute them over the county. The great impetus given to sheep-farming by the frozenmeat industry and the high prices ruling for cereals, together with the use of improved farming-implements and vastly improved methods of tillage, by utilising every available space of land, has greatly reduced the vast numbers of the. less useful and injurious species of naturalised plants formerly abundant on many large areas of the plains. On the swampy parts and on the margins of the numerous water - races traversing the plains Ranunculus sceleratus grows luxuriantly in great profusion. In old pastures R. repens became very plentiful, especially on moist rich land; but it is now much reduced by frequent cultivation of the land for cropping. Papaver rkœas is less plentiful in cornfields than formerly, and P. argemone has made no progress during the last, ten years. The latter only occurs in four districts in the county, and is a very objectionable plant in any pastoral country. Many crucifers were early arrivals with the foul seed imported in the early days, and many species have spread and become naturalised throughout the county. Brassica campestris and B. sinapistrum have long been great scourges, and have in certain years taken almost complete possession of large cultivated areas. As already noted by Mr. Thomson,* Trans. N.Z. Inst., vol. xxx., p. 313. the water-cress (Nasturtium officinale) grows in all the slow-flowing creeks and springs on the river-bed, and attains to proportions never previously observed in Europe. The Caryophylleœ are largely represented. Silene inflata, S. anglica, S. quinquevulnera, Lychnis vespertina, Spergula arvensis, and Arenaria serpyllifolia flourish in conspicuous masses on both cultivated and uncultivated land. The fleshy rooted deep-rooting S. inflata and L. vespertina, when well established, cause hard work to plough-horses and expense to farmers in cropping their lands. S. quinquevulnera, grows abundantly, and frequently produces large spikes of finely developed flowers with varying shades of colour. The naturalised leguminous plants include some of the most aggressive. The gorse (Ulex europœus) and broom (Cytisus scoparius) occupy many thousand acres of the

river-beds and by-roads of the plains, where their growth attains to great dimensions. In some districts they form extensive and impenetrable masses, and have proved good rabbit-warrens. The seed is carried by every water-race and every freshet and flood in the rivers and distributed over the country, and generally grows freely wherever it is deposited. When buried in the silt-beds deposited by the water-races the seed retains its vitality for an indefinite period. Medicago denticudata, the medick-burr, is lees aggressive than formerly, though still unpleasantly plentiful. Trifolium arvense holds almost complete possession of dry, Bandy, and stony situations, and covers many hundreds of acres of such areas in many parts of the county. It forms the chief vegetation growing on the stony slopes and terraces along the sea-coast during summer and autumn. An extensive area of poor land occupied with T. arvense in full bloom exhibits or assumes a marked feature of a desert vegetation. Lotus corniculatus flourishes in neat masses generally on poor land, but it is not plentiful, and disperses slowly. The Rosaceœ comprise ten or more species. Rubus fruticosus, Rosa rubiginosa, R. canina, Fragaria vesca, and Cratœgus oxyacantha have long been naturalised and widely dispersed by the agency of birds. The wild strawberry (F. vesca) is confined to the neighbourhood of the bush and moist warm valleys of the fore hills, and grows in extensive masses. Prunus avium(?) is also dispersing freely in old bush districts, and is doubtless the true species mentioned by De Candolle,* “Origin of Cultivated Plants.” which does not produce suckers. The stonecrop (Sedum acre) is the only representative of its order occurring in the county. It occurs in large patches on farms, and the means whereby it is distributed are not easily elucidated. I believe it to have been sown among unclean seed many years ago, and to have escaped notice until it grew into conspicuous masses during recent years. The gooseberry (Ribes grossularia) has been distributed extensively by birds. The plants form miniature jungles in many old plantations where the introduced birds roost during the night. In the Umbellifereœ the fennel (Fœniculum vulgare), the hemlock (Conium maculatum), and the wild carrot (Daucus carota) are the most regrettable introductions. The two former exist only in a few districts, while the latter covers many acres, and grows dense and strong, especially on neglected old roads and old pastures, and spreads rapidly. Composites are largely represented, and comprise several almost valueless aud some destructive species. From the year

1880 to 1895, when the ruling prices for cereals and sheep were low, farmers remained somewhat inert, permitting their farms to be overrun with objectionable plants. During these years I observed the ox-eye daisy (C. leucanthemum), C. segetum, Anthemis arvensis, Achillea millifolium, Convolvulus arvensis, Carduus arvensis, Onopordium acanthium, Crepis virens, Rumex acetosella, and Taraxacum dens-leonis taking absolute possession of large and valuable paddocks that had been only once or twice ploughed. Needless to say, the cost of clearing the paddocks of these exotic plants within recent years has been prodigious. In wet seasons the daisy (Bellis perennis) blooms freely on the moist river-flats, but it fails to disperse and grow on drier land. Senecio Jacobœa, which has taken possession of many square miles in Southland, occurs in isolated small patches near the hills, but it is rare on the open plains. The introduced species of Convolvulus and the other allied plants listed are widely dispersed, and have proved destructive to cereal and clover crops. In 1893–94 the clover dodder (Cuscuta europœa) destroyed great quantities of red-clover (Trifolium pratense), but is has not been so destructive since those years. The great bind-weed (Calystegia sepium) has proved a great nuisance in some districts on good land, where it roots deeply and is difficult to eradicate. The common Convolvulus arvensis is the most widely dispersed species, and grows freely on almost any soil. In the Boragineœ, Echium vulgare and Lithospermum arvense are the more widely distributed. The former, though producing tall well - developed Bpikes of ultramarine-blue flowers, is an objectionable plant to agriculturists. Nevertheless, a large group of these plants in full bloom is attractive and beautiful. The small-flowered Myosotis arvensis is abundant in many parts of the county, and grows freely in waste places, but more so on the moist margins of water-races or near swampy ground, where it produces neat spikes of its familiar flowers. M. sylvatica occurs in shady parts of the half-cleared bush at Mount Somers, but it is not yet abundant. The Scrophulariaceœ comprise some old garden favourites which were early coiners. Their occurrence on the ranges and in the inland valleys in the early years of settlement prove conclusively that they were not garden escapes. The hoary mullein (Verbascum thapsus) ascends to 5,000 ft. on the lower alps, and grows vigorously in large masses on the shingle slopes and sides of the valleys, producing a striking-contrast to the stunted shrubby subalpine plants. The seed has undoubtedly been carried up the ranges in the wool of merino sheep. These animals, feeding among the plants in the autumn, when the seed is ripe, would shake it from the tall

seed-stems into their wool, and thus freely distribute it. When crossing the Ashburton moraine en route to the upper Rangitata in February last I observed V. blattaria and V. phœniceum growing among the tussocks and snow-grass. The foxglove (Digitalis purpurea) grows abundantly in some of the valleys, where its seed is probably distributed like that of Verbascum. Veronica agrestis, serpyllifolia, arvensis, buxbaumii are plentiful on waste places. The two additional species in the list are not anywhere numerous, and occur, when met with, in old pastures. Bartsia viscosa is one of the commonest of plants on the vast river-beds, where it frequently attains to 2 ft. in height, and produces large and well-developed spikes of its handsome yellow flowers. The labiates include some rare and interesting and alsosome very aggressive plants. The spearmint (Mentha viridis) occurs in large masses on the sandy river-flats, and frequently overgrows damp ditches and water-races crossing the plains. M. pulegium is common on the margins of slow-flowing streams and stagnant lakes, and, like the spearmint, attains to height and vigour unknown in English gardens. Prunella vulgaris, Melissa officinalis, Teucrium scorodonis, Stachys arvensis, S. germanica, and Lamium album occur commonly in old pastures and among the general vegetation of the great river-flats. The plantains are everywhere abundant. Plantago major displays greater vigour when growing on the cool shady side of plantations and on the margins of slow-flowing creeks. The other species occur largely in pastures and by damp hedgerows. P. media is seen at its best on slightly swampy but good land, where it grows in dense masses. The species and varieties of Chenopodium are among the most worthless of naturalised plants. C. album and urbicum have, for thirty years, proved an unmitigated nuisance and expense to farmers in the county. They were the first English weeds to overrun the newly ploughed fields, where they grew and dispersed with great rapidity. Before the introduction of the modern seed-cleaning machinery it was almost impossible to keep the sacks of grain free from the-weeds infesting the fields, and the two plants under notice were the worst of all. Like these plants, other tall-growing weeds were cut and bound up in the sheaves, and their seeds were thus freely distributed over farms. Sheep also greatly assisted by carrying the seed over the country in their wool. From numerous inquiries among the very old colonists resident in the county I have ascertained that docks (Rumex crispus, R. obtusifolius) grew in masses in moist depressions, in the Wakanui district before a plough had turned over a foot of the rich virgin land. Forty-four years ago there were

few or no fences on the plains, and merino sheep roamed free over the great expanse of tussocks. Every freshet in the natural water-channels where they grew would also rapidly distribute the seeds of these and other aggressive plants. Mr. John Cochrane informs me that he observed docks attain a height of 7 ft. in these channels in 1860; and the year following he observed the first thistles (Carduus lanceolatus) in Wakanui, and two years later they were plentiful on good land on the tussock plains. At that time they grew annually 3 or 4 acres of tobacco, which they cut three times, in a season for sheep-dipping purposes. After the tussocks were burned they also sowed seed on the burned areas, which generally produced “more bad plants than good ones.” The second year after-ploughing the land sorrel (Rumex acetosella) spread over it, and soon took possession if not rigorously checked. Since tilling operations commenced about forty years ago sorrel has been a very aggressive and destructive pest. Polygonum aviculare, the so-called wire-weed, and the var. Driandri, are abundant everywhere. P. minus, persicaria, convolvulus, and lapathifolium attain to great perfection on the moist silty river-flats, and display a wealth of flowers during the autumn months. When Mr. Cochrane arrived at the Wakanui sheep-station in 1860 nettles (Urtica dioica, U. urens) were growing about the sheep-yards erected a few years previously. They exist at present in a few hedgerows, but are not troublesome. In wet seasons the seeds of Betula alba, Populus alba, Salix fragilis, S. caprea, and Quercus robur v. pedunculata produce seedlings in masses under old trees. The acorns of the oak have been carried by water-races and other streams crossing the plains and deposited in the silt, on which they grow into good-sized trees in a few years. In the Coniferœ, Pinus insignis, P. pinaster, and Cupressus macrocarpa cast fertile seed and became naturalised fifteen years ago. There are other interesting aspects of the naturalisation of conifers that may be noted. Plants raised from seed of C. macrocarpa grown in the county lack the vigour and grow weaker, more narrow, and more upright than do those grown from imported seed. Notwithstanding that several species of Abies, Picea, and other conifers produce fertile cones and cast seed, I have not up to the present time observed any of them to grow and naturalise under the parent tree. The banks of the north and south branches of the Ashburton River for many miles are overgrown with the weeping willow (Salix babylonica). The Wakanui Creek, from its intake to the sea, a distance of eleven miles, is also shaded by magnificent willows, all self-planted. During gales of

winds small twigs and limbs are broken from the older trees and float to and lodge on the banks, where they readily root and grow into large trees in a few years. When travelling through Wakanui across the open plain the irregular pale green line of high beautiful willows produces an admirable contrast to the small plantations of sombre evergreen pines around the settlers' homes. Prom its artificial mode of dispersal and propagation I have not included this willow in my list of naturalised plants. The basket-willow (S. rubra) and the golden willow (S. vitellina) propagate likewise, but they are not so numerous as is the weeping willow. As previously stated, several species of naturalised plants displayed great vigour and spread rapidly for a few years after their introduction, when their vigour declined and their numbers diminished and became rare or disappeared from large areas where formerly they were abundant. The disappearance of a large number of species is due to severe climatic conditions occurring at intervals of several years on the Canterbury Plains. The protracted drought between 1895 and 1898 very materially checked the progress and reduced the numbers of many species of naturalised plants in the county. Previous to those years large masses of buckwheat (Fagopyrum, esculentum, Mœnch.) grew annually along the railway banks and sides, but I have not observed a single plant since the close of the drought. Several other species that were killed off certain areas by the drought have not up to the present time been able to re-establish themselves in the same numbers as formerly. During the last five years of more or less cool wet weather at all seasons Centaurea nigra and Onopordon acanthium have dispersed rapidly. In the autumn, when the seed is ripe, the plants are visited by large flocks of goldfinches, who attack the flower-heads and scatter the seed in all directions. Echium vulgare, which is fertilised by humble-bees, is also increasing rapidly. Diplotaxis muralis and a tall-growing handsome-flowered Nasturtium which I have been unable to identify were first collected four years ago, but they now occur in several districts. Two plants of the teasel thistle (Dipsacus sylvestris) were sent to me last year from Waterton, but I have not collected it nor heard of its occurrence elsewhere in the county. The present great demand for all classes of arable land, and the extensive ploughing by improved methods proceeding annually, together with the use of strong artificial manures and vastly increasing flocks, will rapidly check and diminish the numbers of both native and naturalised plants excepting on waste places. A sketch of their introduction and progress in a given area during the last half-century will enable botanists of the future to note and

compare their numbers and development, which should be of great interest half a century hence. When the first, colonists arrived the seasons continued for thirty years much more equable and genial than they have been during the remaining, period. The land was rich and fresh, which enabled the newly introduced plants to attain to vigour and development probably never attained by previous generations of the species. During the last ten years many species have not displayed such vigour as formerly, such being probably due to the partial exhaustion of the soil, the modification of the climate under the changed vegetation, and the irruption of other species. In recording these notes it is incumbent upon me to state that I have been for years greatly indebted to Mr. G. M. Thomson, F.L.S., for valued assistance in identifying many of the species for me. The late Professor T. Kirk, F.L.S., also very generously assisted in the identification of many species of grasses in the list. The late Mr. J. F. Armstrong and his son, Mr. J. B. Armstrong, likewise, assisted in identifying and naming species submitted to them at different times after I began to study the naturalised plants some years ago. Mr. G. W. Leadley and Mr. C. Reid, former presidents of the Ashburton Agricultural and Pastoral Association, when in office did valuable service by urging the farmers of the county to collect exotic plants occurring on their farms and bring them to the rooms of the association. By this means I procured several interesting species which I had not previously collected. Of the deceased botanists I cherish thoughts of their kindness, while to those gentlemen who have assisted as stated I would here express sincere thanks. Following is the list of plants collected:— Ranunculaceæ. Ranunculus acris, L., Britain. " sceleratus, L., Britain. " repens, L., Britain. " bulbosus, L., Britain. " arvensis, L., Britain. " parviflorus, L., Britain. Aconitum napellus, L., Britain. Aquilegia vulgaris, L., Britain. Delphinium ajacis, Reichenbach, Europe. Papaveraceæ. Papaver rhœas, L., Britain. " hybridum, L., Britain. " argemone. Glaucium luteum, L., Britain. Chilidonium majns, L., Britain.

Cruciferæ. Cheiranthus cheiri, L., Britain. Nasturtium palustre, D.C., Britain. " officinale, L., Britain. " sp. Diplotaxis muralis. Sisymbrium officinale, L., Britain. Barbarea præecox, Br., North America. " vulgaris, Br., Britain. Brassica oleracea, L., Britain. " napus, L., Britain. " alba, Boiss., Britain. "rapa, L., Britain. " sinapistrum, Boiss., Britain. " campestris, L., Britain. Sinapis nigra, L., Britain. " arvensis, L., Britain. Alyssum maritinum, L., Europe. " orientale, Ard., Europe. " calycinum, L., Europe. Arabis hirsuta, Br., Britain. Cardamine hirsuta, L., Britain. Draba verna, L., Britain. Cochlearia armoracea, L., Britain. Raphanus sativus, L., Britain. Capsella bursa-pastoris, L., Britain. Senebiera coronopus, Poiret, Britain. " didyma, Persoon, Britain. Lepidium ruderale, L., Britain. " campestre, Br., Britain. Iberis amara, L., Britain. Fumariaceæ Fumaria offcinalis, L., Britain. Corydalis lutea, D.C., Britain. Resedaceæ Reseda alba, L., Britain. Violaceæ. Viola tricolor, L., Britain. " odorata, L., Britain. Caryophylleæ. Dianthus barbatus, L., Europe. "armeria, L., Britain. " prolifer, L., Britain. Saponaria officinalis, L., Britain. Silene inflata, Smith, Britain.

Silece nutans, L., Britain. " anglica, L., Britain. " quinquevulnera, L., Britain. " noctiflora, L., Britain. Lychnis diurna, Sibthorpe, Britain. " vespertina, Sibthorpe, Britain. " githago, Lamarck, Britain. " flos-cuculi, L., Britain. Sagina procumbens, L., Britain. Gypsopnylla tuberosa, Boisier, Britain. Stellaria media, Witherington, Britain. " holostea, L., Britain. " graminea, L., Britain. Cerastium vulgatum, L., Britain. " arvense, L., Britain. " triviale, Link, Britain. Polycarpon tetraphyllum, L., Britain. Spergula arvensis, L., Britain. Arenaria serpyllifolia, L., Britain. Spergularia rubra, Persoon, Britain. Hypericineæ Hypericum androsæmum, L., Britain. " perforatum, L. " calycinum, L., Britain. "montanum, L., Britain. Lineæ Linum usitatissimum, L., Britain. " catharticum, L., Britain. Malvaceæ. Hibiscus trionum, L., South Africa. Lavatera arborea, L., Britain. Malva moschæta, L., Britain. " rotnndifolia, L. Britain. " sylvestris, L., Britain. " verticillata, Britain. Althea officinalis, L., Britain. Geraniaceæ Geranium dissectum, L., Britain. " robertianum, L., Britain. " lucidum, L., Britain. " molle, L., Britain. Erodium cicutarium, L. Heritier, Britain. " moschatum, L. Heritier, Britain. Oxalis corniculata, L., Britain. " rosea, Jacquin, South America. Limnanthus donglasii, North America.

Leguminosæ Cytisus scoparius, L., Britain. " albidus, L., North Africa. Ules europæus, L., Britain. Medicago sativa, L., Britain. " lupulina, L., Britain. " denticulata, Wildenow, Britain. Melilotus alba, Lamarck, Britain. " officinalis, L., Britain. Trifolium incarnatum, L., Britain. " medium, L., Britain. " arvense, L., Britain. " hybridum, L., Britain. " ochroleucum, L., Britain. " pratense, L., Britain. " glomeratum, L., Britain. " repens, L., Britain. " procumbens, L., Britain. " minus, Sm., Britain. Lathyrus nissolia, L., Britain. " pratensis, L., Britain. Lotus corniculatus, L., Britain. Onobrychus sativa, Lamarck, Britain. Vicia hirsuta, Koch, Britain. " tetrasperma, Mœnch., Britain. " lutea, L., Britain. " sativa, L., Britain. Lupinus arboreus, Sims, North America. " luteus, L., Europe. Viburnum vulgaris, L., Europe. Rosaceæ Agrimonia eupatoria, L., Britain. Potentilla anserina, L., Britain. Rubus fruticosus, L., Britain. " idaeus, L., Britain. Rosa canina, L., Britain. " rubiginosa, L., Britain. Prunus avium(?), L., Britain. Fragaria vesca, L., Britain. Cratægas oxyacantha, L., Britain. Acæna ovina, Cunn., Australia. Onograreæ ænothera biennis, North America. " stricta, North America. Lythraceæ Lythrum hyssopifolium, L., Britain.

Pobtulaceæ. Portulaca oleracea, L., Europe. Crassulaceæ. Sedum acre, L., Britain. Ribesiaceæ. Ribes grossularia, L., Britain. " sanguinea, Purch, North America. Umbelliferæ. Hydrocotyle vulgaris, L., Britain. Apium graveolens, L., Britain. Petroselinum sativum, Hoffnau, Britain. Fœniculum vulgaris, Gœrtner, Britain. Pastinacea sativa, L., Britain. Scandix pectin-veneris, L., Britain. Daucus carota, L., Britain. Clonium maculatum, L., Britain. Caprifoliaceæ. Sambucus nigra, L., Britain. Rubiaceæ. Gallium aparine, L., Britain. " palustre, L., Britain. Sherardia arvensis, L., Britain. Valerianeæ Centranthus ruber, D.C., Europe. Compositæ. Conyza ambigua, D.C., Europe. Petasites vulgaris, Europe. Erigeron canadensis, L., Britain. Vittadinia australis, A. Rich., Australia. Bellis perennis, L., Britain. Chrysanthemum segetum, L., Britain. " lencanthemum, L., Britain. " parthenium, Persoon, Britain. Matricaria chamomilla, L., Britain. Anthemis arvensis, L., Britain. Calendula officinalis, L., Europe. Achillea millefolium, L., Britain. Tanacetum vulgare, L., Britain. Artemisia absinthium, L., Britain. Gnaphalium luteo-album, L., Britain. " germanicum, Wildenow, Britain Sencoio vulgaris, L., Britain.

Senecio sylvaticus, L., Britain. " Jacobæa, L., Britain. Bidens pilosa, L., Western Asia. Arctium lappa, L., Europe. Cotula australia, Hooker, Australia. Carduus marianus, L., Britain. " lanceolata, L., Britain. " arvensis, Curtis, Britain. " pycnocephalus, Jacquin, Britain. Onopordium acanthium, L., Britain. Centaurea nigra, L., Britain. " cyanus, L., Britain. " calcitrapa, L., Britain. " solstitialis, L., Britain. Tragopogon pratense, L., Britain. Picris hieracioides, L., Britain. Leontodon hirtus, L., Britain. " autumnalis, L., Britain. Hypochœris glabra, L., Britain. " radicata, L., Britain. Sonchus arvensis, L., Britain. " oleraceus, L., Britain. " asper, Hoffman, Britain. Taraxacum dens-leoms, Desfontaine, Britain. Crepis virens, L., Britain. Cichorium intybus, L., Britain. Lapsana communis, L., Britain. Campanulaceæ. Campanula hybrida, L., Britain. Primulaceæ. Primula vulgaris, L., Britain. " polyanthus, L., Britain. Auagallis arvensis, L., Britain. " cerulea, L., Britain. Jasmineæ. Fraxmus excelsior, L., Britain. Apocynaceæ. Vinea major, L., Britain. " minor, L., Britain. Gentianeæ Erythræa centaurium, Persoon, Britain.

Polymoniaæ. Gilia cerulea. Collomia coceinea, Lehman, North America. Convolvulaceæ. Convolvulus arvensis, L., Britain. " sepium, R. Br., Britain. " v. sylvatica, Europe. Cuscuta trifolii, Babington, Britain. " europæa, L., Britain. Boragineæ Echium vulgare, L., Britain. " violaceum, L., Britain. Lithospermum arvense, L., Britain. Anchusa officinalis, L., Britain. Myosotis palustris, Witherington, Britain. " sylvatica, Hoffman, Britain. " arvensis, Roth, Britain. Lycopsis arvensis, L., Britain. Borago offcinalis, L., Britain. Cynoglossum furcatum, Wall, Europe. Solanaceæ. Solanum nigrum, L., Britain. " tuberosum, L., South America. Nicandra physaloides, Gœrtner, Western Asia. Datura stramonium, L., Britain. Atropa belladoona, L., Britain. Lycium barbatum, L., Britain. Scrophulariaceæ. Verbascum thapsus, L., Europe. " blattaria, L., Europe. " phœniceum, L., Europe. Linaria vulgaris, Mœnchner, Europe. " elatine, Desfontaine, Europe. " purpurea, Miller, Europe. " cymbalaria, Miller, Britain. Scrophularia aquatica, L., Britain. Mimulus luteus, Wildenow, North America. " moschatus, Douglas, North America. Digitalis purpurea, L., Britain. Veronica agrestis, L., Britain. " serpyllifolia, L., Britain. " buxbaumii, Tenure, Britain. " arvensis, L., Britain. " officinalis, L., Britain. Bartsia viscosa, L., Britain.

Labiatæ. Mentha viridis, L., Britain. " pulegium, L., Britain. Prunella vulgaris, L., Britain. Mellisa officinalis, L., Britain. Marrubiumv ulgare, L., Britain. Stachys arvensis, L., Britain. " germanica, L., Britain. " annua. Lamium purpureum, L., Britain. " album, L., Britain. Teucrium scorodonis, L., Britain. Verbenaceæ. Verbena officinalis, L., Britain. Plantagineæ. Plantago major, L., Britain. " media, L, Britain. " lanceolata, L., Britain. " coronopus, L., Britain. Chenopodiaceæ. Chenopodium album, L., Britain. " v. glabrum, Britain. " v. viride, Britain. " rabrum, L., Britain. " urbicum, L., Britain. Atriplex patula, L., Britain. " varieties. Polygoneæ. Rumex crispus, L., Britain. " obtusifolius, L., Britain. " pulcher, L., Britain. " acetosa, L., Britain. " acetosella, L., Britain. Polygonum aviculare, L., Britain. " v. dryandri, Britain. " minus, Hudson, Britain. " persicaria, L., Britain. " convolvulus, L., Britain. " lapathifolium, L., Britain. Euphorbiaceæ. Euphorbia peplus, L., Britain. " lathyris, L., Britain. " helioscopia, L., Britain. Mercurialis annua, L., Britain.

Urticeæ. Urtica urens, L., Britain. " dioica, L., Britain. Aceraceæ. Acer campestre. Amentaceæ. Salix fragilis, L., Britain. Betula alba, L., Britain. Populus alba, L., Britain. Quercus robur, L., Britain. " v. pedunculate, L., Britain. Coniferæ. Pinus insignis. " pinaster, Europe. Typhaceæ. Sparganium simplex, Hudson, Britain. Irideæ. Sisyrinchium striatum, Cavanilles, South America. Liliaceæ. Asparagus offcinalis, L., Europe. Juncaceæ. Juncus bufonius, Britain. Gramineæ. Millium effusum, L., Britain. Digitaria sanguinale, Scopoli, Britain. Sclavia verticillata, Palisot, Britain. " glauca, Palisot, Britain. Anthoxanthum odoratum, L., Britain. Phalaris canariensis, L., Britain. Phleum pratense, L., Britain. " arenarium, L., Britain. Alopecurus agrestis, L., Britain. " pratensis, L., Britain. " geniculatus, L., Britain. Lagurus ovatus, L., Britain. Polypogon monspelieneis, Desf., Britain. " littoralis, Sm., Britain. Agrostis alba, L., Britain. " stolonifera, Britain. " v. vulgaris, Britain.

Agrostis canina, L., Britain. Psamma arenaria, Palisot, Europe. Ara caryophyllea, L., Britain. " flexuosa, L., Britain. Avena pubescens, L., Britain. " elatior, L., Britain. " fatua, L., Britain. Trisetum flavescens, Palisot, Europe. Archenatherum avenaceum, Palisot, Britain. " v. bulbosum, Britain. Holcus mollis, L., Britain. " lanatus, L., Britain. Cynodon dactylon, Persoon, Britain. Nardus stricta, L., Britain. Elymus arenarius, L., Britain. Hordeum murinum, L., Britain. " sativum, Hudson, Britain. Triticum repens, L., Britain. " sativum, L., Asia. " caninum, Hudson, Britain. " junceum(?), L., Britain. Lolium perenne, L., Britain. " temulentum, L., Britain. Brachypodium sylvaticum, Palisot, Britain. Bromus sterilis, L., Britain. " mollis, L., Britain. " racemosus, L., Britain. " arvensis, L., Britain. " matritensis, L., Britain. " erectus, Hudson, Britain. " secalinus(?) Hudson, Britain. Festuca ovina, L., Britain. " v. rubra, Britain " v. duriuscula, Britain. " elatior, Britain. " v. pratensis, Britain. " v. loliacea, Britain. Dactylis glomerata, L., Britain. Melica nutans. L., Britain. Cynosurus cristatus, L., Britain. Briza media, L., Britain. " minor, L., Britain. " maxima, L., Europe. Poa procumbens, Curtis, Britain. " annua, L., Britain. " rigida, L., Britain. " pratensis, L., Britain. " neinoralis, L., Britain.

Poa trivialis, L., Britain. Glyceria aquatica, Sm., Britain. " fluitans, R. Br., Britain. " maritima, Sm., Britain. Since the foregoing was written I have collected the under-noted species, some of which have been identified by Professor Cheeseman, F.L.S., and Mr. G. M. Thomson, F.L.S. Pyrus aucuparia was inadvertently omitted from the above list. Salsola kali. Silene armeria. Dipsacus sylvestris. Lepidium draba. Cynara carduneulus. Hieraoium subaudum. Crepis taraxifolia.