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Volume 28, 1895
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Art. XLIX.—On the Products of a Ballast-heap.

[Read before the Wellington Philosophical Society, 26th February, 1896.]

During the summer and autumn of 1892 and 1893 attention was drawn to the introduction of injurious weeds in earth-ballast, as exemplified by the introduction of the cockle-burr* (Xanthium strumarium, L.), in the ballast of the ship “Silver-stream” from Buenos Ayres, which had been temporarily deposited near the Bunny Street entrance to the railway goods-station, Wellington. As the total number of species exceeded one hundred, and 20 per cent. of them were new to the colony, it seems advisable to record this short chapter in the history of the introduction of exotic plants in New Zealand at some length, more especially as the great majority of the newcomers are of South American origin, and hitherto less than a dozen of our naturalised plants have come from, that part of the globe.

The ballast, of which some portion had been removed when I first saw it, originally covered an area of about 40ft. in breadth by 70ft. or 80ft. in length, with a general height of 3ft. or 4ft. It had been clothed with a dense weedy growth, which had been cut down by the railway authorities, who learned the possibility of some of the plants proving noxious from the newspapers of the day. The ballast itself consisted chiefly of soil from cultivated land sparingly mixed with fragments of brick-and other building rubbish. Portions of the earth were distributed some yards beyond the original area during its removal for the formation of a new platform at the passenger-station, so that certain of the plants were scattered for some distance along the line of removal. Although the soil was removed so closely that the old surface was laid bare in most places, numerous seed-containing par-ticles were left behind, when several plants which had not been previously observed made their appearance for the first time.

The total number of plants collected is 104, of which about seventy belong to the great army of combatant weeds which have now become distributed along the great lines of ocean-travel all round the earth, and for the most part appear to find little difficulty in establishing themselves and encroach-ing upon their indigenous congeners when once introduced:

[Footnote] * See Trans. N.Z. Inst., xxvi. (1893), 310.

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these do not enter into the scope of this paper to any material extent. Attention must be directed specially to the twenty species not hitherto observed in the colony, and to the few not previously known to occur in the Wellington Provincial District.

In-October, 1893, after the removal of the ballast, the newly-pared surface soon became clothed with a robust growth of the purslane, Portulaca oleracea, Chenopodium ambrosioides, Panicum crus-galli, and other plants not previously seen under spontaneous conditions in Wellington. From its bright-yellow flowers, which were produced in great abundance, the purslane was remarkably prominent; but, as its showy corollas invariably closed immediately after the hour of noon, the dull appearance of the area in the afternoon formed a remarkable contrast with its morning brightness. Amongst these plants were others of great rarity, although very inconspicuous: Petunia parviflora, Euphorbia ovalifolia, Roubieva multifida, Nicotiana acutiflora, Eragrostis minor, Acicarpha tribuloides, Setaria imberbis, nearly all of which are natives of South America. Scarcely any of these were to be seen before the ballast was removed. Amongst the plants of the first year were Cheno-podium ficifolium, Emex australis, Alternanthera sessilis, Galinsoga parviflora, Echium plantagineum, Cenia turbinata, Bowlesia tenera, Cichorium endivium, none of which made their appearance the second year except the Chenopodium, which occurred in some quantity, and was represented by a few straggling specimens last year, although not a scrap is to be seen at this date. In all probability the soil would still be productive if slightly broken up to the depth of a few inches.

Xanthium strumarium made its appearance the first year, numerous specimens were observed during the second year, and four or five were seen last year. When growing on the stiff clay it assumed a stout, robust appearance, differing widely from its usual appearance in Europe. None of the Wellington specimens exhibited the luxuriance shown by those of Australian growth, and, as it does not develope flowers and fruit until March and April, it is scarcely probable that it will become permanently established in this part of the colony. It would doubtless have a more favourable chance on the light soils of the Auckland Isthmus. Roubieva mullifida assumed a very robust growth, and there seemed some probability of its being able to maintain its existence, although it failed to ripen seeds, as several strong plants were growing at the commencement of March, but most of them disappeared during the winter months, probably from injuries caused by cattle quite as much as by the severe frost. As the area is now mostly covered with a thick growth of common weeds, intermixed with patches of cocksfoot, meadow-grass, and rye-grass, there is but little probability of the rarer species again making their

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appearance unless the surface should be disturbed. The species still to be found, although in small quantity only, are Erodium malacoides and Chenopodium ambrosioides, of each of which a few specimens are making a good fight against the coarser weeds; Petunia parviflora, now represented by three small plants only; and the plant here identified as Aster im-bricatus, which has increased to a small extent : it may be expected to become permanent, together with the Erodium, although the latter is too much at the mercy of accident.

Amongst the plants developed on the ballast are three in-digenous to New Zealand, although extending to other countries. Dichondra repens, Forst., made its appearance in small quantity during the first year, but plentifully the second year, and in small quantity last year; this year it is not in evidence. It has a wide distribution in temperate and extra-tropical countries in the Southern Hemisphere, so that its reintroduction from South America is not a matter for surprise. Another species, Cotula coronopifolia, is still more widely distributed, as it extends to Europe, and occurs in a naturalised condition in the British Islands: its range appears to be extending.

Cotula australis, Hook, f., has, however, a more limited distribution, being apparently confined to New Zealand, Australia, and Tristan d'Acunha. Unless, like its congener, C. coronopifolia, it is becoming naturalised in distant countries, the seeds must have been mixed with the ballast in Wellington, although this is somewhat improbable.

Emex australis did not appear after the first year. This South African plant requires a warmer climate than that of Wellington. In Queensland and other tropical countries it has become a great pest: on two occasions it made its appearance in the Auckland District, but did not prove permanent.

I append a list of the plants collected on the ballast and on the soil where it was deposited during the last three years :—

Note.—Species not previously observed in the colony are distinguished thus (*), and those not previously observed in the Wellington Provincial District thus (†).

Fumariaceæ.

  • Fumaria muralis, Sonder.

Cruciferæ.

  • Barbarea præcox, R. Br.

  • Sisymbrium officinale, L.

  • Brassica napus, L.

  • Capsella bursa-pastoris, DC.

  • Senebiera coronopus, Poiret.

  • " didyma, Pers.

  • Lepidium ruderale, L.

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Caryophyllaceæ.

  • Silene anglica, L., var. quinquevulnera.

  • Cerastium triviale, Link.

  • Stellaria media, L.

  • Spergula arvensis, L.

  • Spergularia rubra, St. Hilaire.

  • Polycarpon tetraphyllum, L.

Portulaceæ.

  • †Portulaca oleracea, L. Naturalised in Auckland.

Malvaceæ.

  • Malva parviflora, L.

  • Modiola multifida, Mænch.

Geraniaceæ.

  • †Erodium malacoides, Willd. Naturalised at the Bay of Islands, 1867, but not observed elsewhere.

Leguminosæ.

  • Ulex europæus, L. Only two plants observed.

  • Medicago sativa, L.

  • " lupulina, L.

  • " denticulata, Willd.

  • Melilotus arvensis, Wall.

  • Trifolium repens, L.

  • " minus, L.

  • " resupinatum, L.

Umbelliferæ.

  • *Bowlesia tenera, Spreng. Monte Video, Brazil, &c.

  • †Apium leptophyllum, F. Muell.

  • Fœniculum vulgare, Gært.

Rubiaceæ.

  • Sherardia arvensis, L.

Calycereæ.

  • *Acicarpha tribuloides, Juss. Buenos Ayres.

Compositæ.

  • *Aster imbricatus, Walp.

  • Erigeron canadensis, L.

  • †Erigeron linïfolius, Willd. Naturalsed in Auckland and Nelson.

  • *Gnaphalium purpureum, L. Florida, Carolina, &c.

  • " luteo-album, L.

  • *Xanthium strumarium, L. Naturalised in most warm countries; but, although numerous specimens made their appearance, very few seeds, if any, were perfected, and the plant has died out.

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  • Xanthium spinosum, L.

  • *Pascalia glauca, Ontega. In various parts of South America.

  • Only two specimens observed on the ballast.

  • *Galinsoga parviflora, Cav. Monte Video, Brazil, &c.

  • Anthemis cotula, L.

  • Chrysanthemum inodorum, L.

  • Cotula coronopifolia, L. Indigenous in New Zealand, also in South Africa, extra-tropical South America, and some parts of Europe.

  • Cotula australis, Hook. f. New Zealand, Australia, and Tristan d'Acunha; so that it must either be naturalised in Monte Video or seeds must have become mixed with the ballast in Wellington.

  • *Cenia turbinata, Pers. Cape of Good Hope. This also appears to have become established at Monte Video. Only a few specimens observed on the ballast.

  • Senecio vulgaris, L.

  • Cryptostemma calendulacea, R. Br.

  • Cnicus lanceolatus, L.

  • *Cichorium endivium, Willd. Originally from eastern and northern India, but now established in many warm countries. Only a few specimens noticed.

  • Lapsana communis, L.

  • Picris echioides, L.

  • Crepis virens, L.

  • Leontodon hispidus, L.

  • Hypochæris radicata, L

  • Sonchus asper, Hoffm.

Primulaceæ.

  • Anagallis arvensis, L.

  • " var. cærulea.

Boragineæ.

  • †Echium plantagineum, L. A few specimens were observed, but the showy flowers were so attractive that they were speedily plucked, and the plant died out. Naturalised in Auckland.

Convolvulaceæ.

  • Dichondra repens, Forster. Identified in the absence of flowers. A native of New Zealand, but found also in many parts of South America.

Solanceæ.

  • *Nicotiana acutiflora, St. Hil. Brazil. Only a few specimens seen.

  • *Petunia parviflora, Juss. South Brazil, Monte Video, &c.

    Only a few specimens seen.

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Scrophularineæ.

  • Verbascum blattaria, L.

  • Veronica arvensis, L.

Plantagineæ

  • Plantago major, L.

  • " lanceolata, L.

Amaranthaceæ.

  • *Amaranthus deflexus, L. Europe.

  • †Alternanthera sessilis, R. Br. Indigenous on the Auckland Peninsula. Found in many tropical and extra-tropical countries.

Chenopodiaceæ

  • Chenopodium album, L.

  • * " ficifolium, L. In great abundance (Europe).

  • " murale, L.

  • †Chenopodium ambrosioides, L. Possibly indigenous on the Auckland Peninsula and in Taranaki, but not previously observed in Wellington.

  • *Roubieva multifida, Moq. Buenos Ayres, Brazil, &c.

  • Atriplex deltoidea, Bab.

Polygonaceæ.

  • Polygonum convolvulus, L.

  • Rumex pulcher, L.

  • " obtusifolius.

  • " sanguineus, L., var. viridis.

  • " acetosella, L.

  • †Emex australis, Stein. South Africa. Naturalised in many warm countries. Has been collected in Auckland and Tauranga, but soon dies out.

Euphorbiaceæ.

  • Euphorbia peplus, L.

  • *" ovalifolia, Engl. Chili, Mendoza, Monte Video, &c.

Urticaceæ.

  • Urtica urens, L.

Cyperaceæ.

  • Cyperus vegetus, Willd.

Gramineæ.

  • *Paspalum dilatatum, Poir. Brazil, &c.

  • Panicum sanguinale, L.

  • †Panicum colonum, L. Naturalised in Auckland, but very rare at present.

  • †Panicum crus-galli, L. This was very plentiful, but has completely died out. It is naturalised in Auckland.

  • *Setaria imberbis, R. et S.

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  • Phalaris canariensis, L.

  • Avena sativa, L.

  • " strigosa, Schreb.

  • Cynodon dactylon, L.

  • *Eleusine coracana, Gært. Monte Video, Brazil, &c.

  • *Eragrostis minor, Host. Brazil, La Plata, &c.

  • Dactylis glomerata, L.

  • Briza minor, L.

  • Poa annua, L.

  • †Glyceria rigida, Sm. Hawke's Bay, Otago, &c.

  • Bromus unioloides, DC.

  • " sterilis, L.

  • * " vestitus, Thunb. South Africa.

  • Lolium perenne, L.

  • " italicum, A. Br.

  • " temulentum, L.

  • Lepturus incurvatus, L.

  • Hordeum murinum, L.

I am indebted to the Director of the Royal Gardens, Kew, for the authentication of most of the South American species.

Note.—As this paper was written in September, it may be advisable to state that the position of several of the surviving species has somewhat improved during the interval. Aster imbricatus has increased to a considerable extent, and Cheno-podium ambrosioides is more plentiful. Roubieva multifida must have produced perfect seeds, as it has increased considerably, although I failed to detect them; several plants of Petunia parviflora have made their appearance; and there are about a score specimens of Chenopodium ficifolium; while the old plants of Pascalia glauca have developed new stems, which seem likely to produce flowers in April.

It will be remembered that the ballast was used in the formation of a platform at the passenger station. The surface of the platform has been covered with asphalt; but beyond the asphalted portion I found three specimens of Pascalia, and in the immediate vicinity several plants of Roubieva and Chenopodium ficifolium. Should the platform be broken up during the twentieth century, most of the plants, enumerated in the list will doubtless make their appearance in profusion.

1st March, 1896.