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Volume 86, 1959
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Contributions to a Knowledge of the Adventive Flora of
New Zealand, No. 7

[Read before Christchurch Branch, July 3, 1957.]


The adventive species present in this remnant of indigenous lowland swamp forest are listed, and number 143, compared with an indigenous flora of 96 species. Daphne laureola L., Poa infirma H. B. K., Taxus baccata L., and Euonymus phellomana Loes, are recorded as new for the adventive flora of New Zealand, the last named species being abundant in the shrub layer.

The Adventive Flora of “Riccarton Bush” (or Deans Bush)—a Remnant of Modified Indigenous Swamp Forest in Lowland Canterbury

Perhaps the most studied and the most written of botanical site in lowland Canterbury, this small but very well-known forest remnant is the last remnant of indigenous lowland forest on the Canterbury Plains in the vicinity of Christchurch.

This forest remnant is situated on the south bank of the Avon River at Riccarton, being about three miles from the centre of the city of Christchurch. The site (altitude ca. 50ft) was very swampy in its original state, but as a consequence of drainage associated with settlement about the remnant the habitat has become progressively more modified, and the ground surface level has sunk a foot or more.

Originally (ca. 1843) about 55 acres in extent, half of the forest was given in 1850 to the Canterbury settlers for firewood and building purposes, while the balance was retained by the Deans family as a reserve, a belt of English trees being planted round it to protect the forest from the heavy winds. The present day area of actual forest is 15 acres, with an adjacent four acres partly planted to indigenous trees and shrubs.

Riccarton Bush was constituted a permanent reserve by the Riccarton Bush Act, 1914, and is administered by a Board of Trustees representative of the Deans family, the Christchurch City Council, Riccarton Borough Council, Waimairi County Council, Paparua County Council, Heathcote County Council, and the Royal Society of New Zealand.

The land itself was a gift of the Deans family. The finance for administration and maintenance depends on annual allocations from the local bodies mentioned.

This forest remnant has been studied from about 1870 onwards, and a number of botanists—Armstrong (1870), Cockayne (1906, 1914), Bird (1916), Wall (1922, 1923, 1953), Murray (1924, 1950)—have described the vegetation, and a number have listed the indigenous species present. The last enumeration of species by Murray (1950: 31—34) lists 96 indigenous species.

A small number of species, possibly in part indigenous, in part adventive—e.g., Gnaphalium luteo-album L. have been included in the several lists of indigenous species, but to date the adventive species have never been enumerated, nor has their progressive significance in the vegetation been mentioned other than incidentally.

Cockayne (1914: 21) implies the presence of adventive species when he states that, “In order to restore the bush to its primitive condition all foreign species should

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be gradually removed ….” Wall (1922: 20, 1953: 40) is much more definite on the status of the adventive species when he writes: “Ferns and other plants of the forest-floor are still fairly abundant, but this part of the reserve is not at all in a satisfactory state. Far too great a number of aliens have got a footing, and the very existence of the native ground-flora is threatened by them.”

The first mention of the actual species occurring is by Deans (1924: 10) when he states: “When the bush was taken over by the Trustees, it was found that parts of it were overrun with elderberry [Sambucus], and that wild cherries [prunes] and certain exotic trees had invaded other parts.…”

As it stands at present, this forest reserve is in effect a collection of micro-habitats—(a) forest, (b) forest margins, (c) forest clearings, (d) bare tramways, (e) grassed tramways, (f) grassy waste land and (g) cultivated land.

It is apparent that over the years a number of introduced woody and herbaceous species have been deliberately planted, some having reproduced and spread subsequently; other species have come in as garden escapes and garden outcasts from adjacent residential sections, while the remaining species have come in incidentally and accidentally by animal, wind or other agency.

The present vegetation of this remnant is not that which existed when the first observations were made; it is a new vegetation, a blend of indigenous and adventive elements with the adventive element now very significant in the shrub and herb layers.

It is unfortunate that over the years that the remnant has been studied there has been no enumeration of the adventive species, no account of their introduction and of their increasingly significant role in the vegetation, but, be that as it may, it is considered that even a preliminary listing of the adventive species at this time is desirable.

The list of species which follows results from personal observation and recordings over a period of eighteen months, and while it is not presented as complete, it will serve as a checklist of species known to occur at the present time, and will serve as a basis for comparison in the future.

The assemblage of adventive species must, I suggest, be regarded as unusual, perhaps not duplicated elsewhere in the world, considering the limited area involved, and the geographic regions represented in the adventive flora.

The species are listed alphabetically with comment restricted to those significant in the vegetation, or noteworthy for some other special reason.

List of Species

  • Acre pseudoplanatus L. (Acreage)

  • Agropyron repents (L.) Beau. (Grannie)

  • Agnostics stolonifera L. p.p. (Grannie)

  • A tennis Sight.(Grannie)

  • Alopecias gesticulates L. (Grannie)

  • A pretenses L. (Grannie)

  • *Amelanchier sandiness (L.) Med (Rosaceae) Two small trees on margin.

  • Aphanites microcopy (Boiss. et Reut.) Rothm. (Rosaceae)

  • Arrhenatherum elatius (L.) J. et C. Presl (Gramineae)

  • Arum italicum Mill. (Araceae)

  • Asparagus officinalis L. (Liliaceae)

  • *Azara microphylla Hk. f. (Flacourtiaceae). A single small tree in forest.

  • Bellis perennis L. (Compositae)

  • Berberis darwinii Hk. (Berberidaceae). Occasional shrub and seedlings.

  • B. vulgaris L. (Berberidaceae). Seedlings only noted.

[Footnote] * Throughout this paper

[Footnote] * denotes species which should not be added to the list of adventive species for New Zealand.

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Brassica campestris L. (Cruciferae).

Bromus sp. (Gramineae). A member of the subgenus Ceratochloa (Beauv.)

Griseb., this plant differs from the related and common B. catharticus Vahl in the stiffly erect panicles and longer, hairy, distinctly awned spikelets. The plant is not uncommon about Christchurch and down the cast coast of the South Island as far south as Oamaru, and is conspicuous by its production of panicles during autumn and winter.

B. carinatus Hk. et Arn. (Gramineae). According to V. D. Zotov, Botany Division, D.S.I.R., there is some doubt as to whether this plant is in fact true B. carinatus, but the name is here used in the sense of Allan (1940: 232).

B. catharticus Vahl (Gramineae).

B. gussonii Parl. (Gramineae).

B. mollis L. (Gramineae).

Calystegia sylvatica (Willd.) Rocm. et Sch. (Convolvulaceae). Spreading into reserve from hedgerows of adjoining sections.

Campanula rapunculoides L. (Campanulaceae)

Capsella bursa-pastoris (L.) Med. (Cruciferae)

Cardamine hirsuta L. (Cruciferae).

Cerastium glomeratum Thuill. (Caryophyllaceae).

C. vulgatum L. (Caryophyllaceae).

Chenopodium album L. (Chenopodiaceae)

C. murale L. (Chenopodiaceae)

Cirsium arvense (L.) Scop. (Compositae)

C. vulgare (Savi) Ten. (Compositae)

Clematis vitalba L. (Ranunculaceae). Occasional plants scrambling over shrubs.

Conium maculatum L. (Umbelliferae)

Cotoneaster francheti Boiss. (Rosaceae). Seedlings and young plants noted.

C. simonsii Baker (Rosaceae). Seedlings and occasional shrubs present. Cotula australis (Sieb.) Hk. f. (Compositae).

Crataegus monogyna Jacq. (Rosaceae). Seedlings and young plants occasional.

Crepis capillaris (L.) Wallr. (Compositae)

C. taraxacifolia Thuill. (Compositae).

Dactylis glomerata L. (Gramineae).

Dapline laureola L. (Thymeleaceae). Reproducing and establishing freely in forest. In view of the recreational use of this reserve, attention is drawn to the poisonous nature of the species; Forsyth (1954: 70) states, “The spurge laurel (D. laureola), like its cousin the mezereon, is extremely poisonous in all its parts, especially the bark and berries. Children are attracted by the berries and death may result from eating them.” (BD. 83273.)

Digitalis purpurea L. (Scrophulariaceae)

Dryopteris filix-mas (L.) Schott (Polypodiaccae)

Duchesnea indica (Andrew) Focke (Rosaceae). Abundant in clearings, about forest margins, and on forest floor, in parts forming distinct communities with Lamium album and Viola odorata.

Epilobium sp.

Erodium cicutarium (L.) L'Herit. (Geraniaceae)

E. moschatum (L.) L'Herit (Geraniaceae)

Euonymus europaeus L. (Celastraceae). Occasional seedlings and shrubs.

E. phellomana Loes. (Celastraceae). Abundant in all stages marginally and through the forest, and now a prominent member of the shrub layer. The seedlings are a distinct feature on the floor (BD. 68063.)

*E. radicans Sieb. (Celastraceae). A single immature plant in a clearing appears to be a variegated form of this species.

[Footnote] † Throughout this paper † denotes species recorded for the first time for New Zealand.

[Footnote] ‡ The identity of this plant will be discussed in a subsequent paper.

[Footnote] † Throughout this paper † denotes species recorded for the first time for New Zealand.

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Euphorbia peplus L. (Euphorbiaceae)

Fragaria vesca L. (Rosaceae). Less common than Duchesnea indica, and much less significant in the herb layer.

Fraxinus excelsioi L. (Oleaceae). Seedlings not uncommon on floor; cut stumps showing regrowth.

Galium aparine L. (Rubiaceae)

Glyceria fluitans (L.) R. Br. (Gramincae). Occasional plants in swampy clearings.

Hedera helix L. (Araliaceac). Forming mats or colonies on floor and on trunks of several tree species—Coprosma robusta Raoul. Cordyline australis (Forst. f.) Hook. f., Elaeocarpus hookerianus Raoul, Pittosporum eugenioides A. Cunn., P. tenuifolium Banks ct Sol. ex Gaertn., Podocarpus dacrydioides A. Rich., P. totaia D. Don, and Quercus robur L.

Heracleum sphondylium L. (Umbelhferae). Occasional in grass in clearings in damp aspects.

Holcus lanatus L. (Gramineae)

Hordeum murinum L. (Gramineae).

Hypericum androsaemum L. (Hypericaceac). Host to the rust Melampsora hypericorum (DC) Winter.

Hypochaeris radicata L. (Compositae)

Ilex aquifolium L. (Aquifoliaceae). Occasional seedlings and small shrubs.

Iris foetidissima L. (Iridaceae). Extensive colonies on floor and in clearings. occasional in grass. Blue and yellow-flowered forms occur, the latter the more abundant.

Lamium album L. (Labiatae). Colonies in grassy places and occasional in clearings.

L. amplexicaule L. (Labiatae)

L. purpureum L. (Labiatae)

Lapsana communis L. (Compositae)

Lavatera cretica L. (Malvaceae)

Leontodon leysseri (Wallr.) Beck. (Compositae)

Leucojum aestivum L. (Amaryllidaceae)

Ligustrum vulgare L. (Oleaceae). Occasional seedlings and older plants, and one colony of mature shrubs on margin.

Lolium multiflorum Lam. (Gramineae)

L. perenne L. (Gramineae)

Lonicera japonica Thunb. (Caprifoliaceae). Scattered vines through forest, with several extensive clearings completely obliterated by the species, which appears to be competing successfully with Muehlenbeckia australis (A. Cunn.) Meissn., Parsonsia sp., and Tetrapathaea tetrandra (Banks et Sol. ex DC) Checscm. Occasional shoots show leaves in whorls of threes.

Lunaria sp. (Cruciferae)

Malva sp. (Malvaceae)

Medicago lupulina L. (Papilionaceae)

Myosotis sylvatica Ehrh. (Boraginaceae). Colonies in grass about margins, along tracks, on floor and in clearings, associated with Duchesnea indica and Lamium album.

Narcissus x biflorus Curt. (Amaryllidaceae)

N. incomparabilis Mill. (Amaryllidaceae)

N. poeticus agg. (Amaryllidaceae)

N. pseudo-narcissus L. (Amaryllidaceae)

Oxalis corniculata L. (Oxalidaceae). Not recorded in earlier lists of indigenous species, this species, which is almost certainly in part indigenous, in part adventive, is perhaps best regarded as adventive in this occurrence.

O. latifolia H. B. K. (Oxalidaceae)

Pastinaca satwa L. (Umbelliferae).

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Phleum pratense L. (Gramineae)

Pctasites sp. (Compositae)

Poa annua L. (Gramineae)

P. infirma H. B. K. (Gramineae)

P. pratensis L. (Gramineae)

P. trivialis L. (Gramineae)

Polygonum aviculare L. (Polygonaceae)

Prunella vulgaris L. (Labiatae)

Prunus avium L. (Rosaceae). Occasional trees, and with some dense thickets of regeneration growth from old cut stumps.

P. cerasifera Ehrh. (Rosaceae). Scattered shrubs in clearings and marginal.

P. lauro-cerasus L. (Rosaceae). Seedlings scattered through forest.

Ranunculus ficaria L. (Ranunculaceae)

R. repens L. (Ranunculaceae)

Quercus robur L. (Fagaceae). Seedlings scattered through forest, more common near margin planted to this species.

Ribes glutinosum Benth. (Grossulariaceac). Occasional: one small plant noted as epiphytic in crotch of twisted trunk of Podocarpus dacrydioides.

R. uva-crispa L. (Grossulariaceae). Seedlings and immature shrubs noted.

Rosa rubiginosa L. (Rosaceae). Occasional seedlings.

Rubus fruticosus agg. (Rosaceae). Colonies established in clearings.

R. idaeus L. (Rosaceae)

R. laciniatus Willd. (Rosaceae). Growing with other entities of the Rubus complex.

R. phoenicolasius Maxim. (Rosaceae). Occasional seedlings and older plants present.

Rumex conglomeratus Murr. (Polygonaceae)

R. crispus L. (Polygonaceae)

R. obtusifolius L. (Polygonaceae)

Sagina apetala L. (Caryophyllaceae)

S. procumbens L. (Caryophyllaceae)

Salix cinerea L. (Salicaceae). Several shrubs in damp situations.

Sambucus nigra L. (Caprifoliaceae). Occasional. A small plant noted as epiphytic in crutch of tree of Podocarpus dacrydioides.

Sarothamnus scoparius (L.) Wimmer (Papilionaceae). Seedlings only noted.

Scilla non-scripta (L.) Hoffmg. et Link (Liliaceae)

Senecio vulgaris L. (Compositae).

Silene gallica L. (Caryophyllaceae)

Sisymbrium officinale (L.) Scop. (Cruciferae)

S. orientale L. (Cruciferae)

Solanum dulcamara L. (Solanaceae). Abundantly established in grassy places and about forest margins, scrambling over shrubs. The dead stems are a prominent winter feature, and the bright red berries pendant from the scandent stems are abundant and noteworthy in autumn. The normal purple and whitish-flowered forms occur.

In view of the frequent use of Riccarton Bush as a recreation area by children, the poisonous nature of this plant must be stressed—all parts of the plant are poisonous, and Forsyth (1954—56) notes: “Children may be attracted to the berries, and cases of poisoning by them are known.”

S. nigrum L. (Solanaceae). Recorded in earlier lists of indigenous species, but included here as perhaps in part adventive.

S. tuberosum L. (Solanaceae)

[Footnote] ‡ The record of this species by Healy (1944: 227) was stated to be the first for New Zealand. this has been found to be incorrect, the earliest being that by Muriay (1924: 30) relative to Riccarton Bush, wherein she states: “ and a climbing Solanum, an introduced species, whose scarlet berries make a bright patch of colour in March and April.”

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Sonchus arvensis L. (Compositae)

S. asper (L.) Hill (Compositae)

S. oleraceus L. (Compositae)

Sorbus aucuparia L. (Rosaceae). Seedlings and young plants abundant marginally about planted oaks; occasional elsewhere.

Stellaria graminea L. (Caryophyllaceae)

S. media L. (Caryophyllaceae)

Taraxacum officinale Weber (Compositae)

*Taxus baccata L. (Taxaceae). Scattered seedlings and older plants marginally and through forest—derived from a planted tree. There appears to be no previous record of this species occurring spontaneously in New Zealand.

Trifolium dubium Sibth. (Papilionaceae)

T. pratense L. (Papilionaceae)

T. repens L. (Papilionoceae)

Tropaeolum speciosum Poepp. ct Endl. (Tropaeolaceae)

Urtica urens L. (Urticaceae)

Veronica arvensis L. (Scrophulariaceae)

V. persica Poir. (Scrophulariaceae)

Viburnum tinus L. (Caprifoliaceae). Occasional shrubs and seedlings.

Vicia angustifolia (L.) Reich. (Papilionaceae)

V. hirsuta L. (Papilionaceae)

V. sativa L. (Papilionaceae)

Vinca major L. (Apocynaceae)

Viola odorata L. (Violaceae). Whitish-flowered forms in colonies on forest floor.

The above enumeration shows an adventive flora of 143 species, made up of 35 woody and shrubby species, 7 climbing or twining species, and 101 herbaceous species (including 1 fern). Of the shrubby element, 28 species have succulent fruits and are almost certainly dispersed by bird agency, while 3 species have wind-dispersed fruits; of the climbing or twining element, 4 species are almost certainly dispersed by bird agency, and 1 species by wind: in the herbaceous element, 6 species have succulent fruits, 13 species have wind-dispersed fruits or seeds, and 22 species have fruits with hooks or hairs which would aid dispersal by animals.

Literature Cited

Allan, H. H., 1940. A Handbook of the Naturalized Flora of New Zealand. N. Z. Dept. S. and I. R., Bull. No. 83.

Armstrong, J. F., 1870. On the Vegetation of the Neighbourhood of Christchurch. including Riccarton, Dry Bush, etc. Trans. N. Z. Inst., vol. 2, pp. 118—128.

Bird, J. W., 1915. Observations on the Lianes of the Ancient Forest of the Canterbury Plains of New Zealand. Trans. N. Z. Inst., vol. 48, pp. 315—51.

Cockayne, L/, 1906. Riccarton Bush. List of the Flowering Plants and Ferns, with introductory note, etc. Christchurch: Lyttelton Times Co.

—— 1914. Riccarton Bush (The Ancient Forest of the Canterbury Plains). The Journal of the Canterbury Agricultural and Pastoral Association, Vol. 2 (3rd Series), pp. 20—1.

Deans, J., 1924. How the Bush was Preserved. In “Riccarton Bush,” edited by C. Chilton. Christchurch: Canterbury Publishing Co., Ltd.

Forsyth, A. A., 1954. British Poisonous Plants. Ministry of Agriculture and Fisheries,, Bull. No. 161.

Healy, A. J., 1944. Some Additions to the Naturalised Flora of New Zealand. Trans. Roy. Soc. N. Z., vol. 74, p. 227.

Murray, F. B., 1924. Botany of Riccarton Bush. In “Riccarton Bush,” edited by C. Chilton. Christchurch: Canterbury Publishing Co., Ltd.

—— 1950. Botany of Riccarton Bush. In “Riccarton Bush Reserve.” Christchurch: H. W. Bullivant & Co. Ltd.

Wall, A., 1922. The Botany of Christchurch. Christchurch. Lyttelton Times Co. Ltd.

—— 1923. The Riccarton Bush. Christchurch: The Lyttelton Times Co., Ltd.

—— 1953. The Botany of Christchurch. Edition 2. Wellington: A. H. & A. W. Reed.