travelling on the shores of Lake Taupo in 1839, "found a fine plant of wheat. The natives could not say how it got there, and Mr Chapman, the Missionary, was the only European who had ever been there, and that only three weeks before."

At the present time wheat only occurs wild as a very occasional escape from cultivation.

Triticum caninum, Huds.

Recorded by W. W. Smith in 1903 as occurring in Ashburton County; not found since.

Triticum junceum, Linn.

Recorded by W. W. Smith in 1903 from Ashburton County; not gathered since.

Elymus arenarius, Linn. Sea-lyme Grass

The Agricultural Department reports this as well distributed in New Zealand, but it is everywhere a planted species, which has been utilised in several parts for binding sand-dunes. It does not appear to have spread anywhere.

Hordeum vulgare, Linn. Barley

Probably included in the corn sown by Captain Cook in 1773 in the gardens in Queen Charlotte Sound. Only occurs as an escape from cultivation, and nowhere grows as a wild species.

Nicholas, who accompanied Marsden to New Zealand in 1814-15, speaks of a plantation of Siberian barley at the Bay of Islands in February of the latter year.

A correspondent of the Farmers' Union Advocate gives the following interesting extract from the diary of the late Rev. J. G. Butler:

On the morning of Wednesday, May 3, 1820, the agricultural plough was for the first time put into the land of New Zealand at Kiddikiddi (Kerikeri), and I felt much pleasure in holding it after a team of six bullocks, brought down by the "Dromedary." I trust that this auspicious day will be remembered with gratitude and its anniversary kept by ages yet unborn. Every heart seemed to rejoice on the occasion. I hope it will still continue to increase, and in a short time produce an abundant harvest.

The results of the ploughing were reaped from 12th December, 1820, to 8th January, 1821, regarding which Mr Butler wrote: "While I am writing down these lines, I have seven natives in sight reaping down a field of barley on land which 12 months ago was overrun with ferns." The Rev. Mr Butler left New Zealand in 1823 and returned about 1840, and settled at Petone, where he died.

Hordeum murinum, Linn. Barley Grass; Way-bent

First recorded from Auckland Province in 1869 by Kirk. It is a most abundant weed now (1917) in waste ground, especially near the sea. The seed gets into the wool of sheep, and frequently causes a certain amount of deterioration.

Hordeum maritimum, With. Squirrel-tail Grass

First recorded in 1871 from Canterbury by Armstrong. In the Manual (1906) it is reported from Akaroa, on the authority of Kirk1.

Order FILICES

Tribe POLYPODIEÆ

Pteris cretica, Linn.

This species was collected near Tapuacharuru, Taupo, and described by Colenso as P. lomarioides, Col., in 1880. A specimen was also found in Oxford Forest, Canterbury, by Mr Vincent Pyke in 1883, and sent down to the author for identification. This was gathered in the bush, away from the immediate vicinity of settlement, and Mr Pyke was certain that it was indigenous.

Pteris longifolia, Linn.

Stated by Buchanan (1882) to have been gathered at Tarawera, between Napier and Taupo, by Mr Lascelles of Napier. Buchanan says it was collected "under circumstances which preclude the possibility of its having been introduced." No one has yet recorded how far fern-spores have travelled on air-currents.

Tribe OSMUNDEÆ

Osmunda regalis, Linn. Fern-royal

This fern was found by Dr Curll at one spot in Rangitikei, from whence it disappeared, and was rediscovered at the same place by H. C. Field of Wanganui in 1885. It does not seem to have spread. The introduction of all three species of foreign ferns was probably quite accidental in each case.

Order LYCOPODIACEÆ

Selaginella denticulata, Link.

Cheeseman (1919) reports, on the authority of T. H. Trevor, that this species has been known for many years as a garden escape at Pakaraka, Bay of Islands, and has lately appeared in great abundance on the banks of several swampy creeks in the neighbourhood. B. C. Aston also reports it as not uncommon in several localities near Wellington.

1 In 1871 Armstrong recorded Hordeum distichum, from Canterbury. The species has not been observed since.

THE eno

Part IV

Chapter XIII

INTERACTION OF ENDEMIC AND

INTRODUCED FAUNAS

HE enormous impetus given to Natural History by the publication of Darwin's Origin of Species in 1859 led many of those who were interested in biological studies in New Zealand to give much consideration to the relation of his theoretical views to the problems which faced them here. I was among those who came early under the spell. I read with care and avidity every work of Darwin's which bore on the subject of evolution and natural selection, and followed this up by a careful study of contemporary writers, Hooker, Lyell, Huxley, Wallace, Asa Grey, Haeckel and numerous others. As a lad I had some slight knowledge of the British fauna, and had begun to collect the flora under my old teacher of botany, Professor John Hutton Balfour of Edinburgh. I made extensive botanical and zoological collections in many parts of New Zealand from the Bay of Islands to the south of Stewart Island between 1868 and 1892, collaborating first with that prince of field naturalists, Captain F. W. Hutton, and later with Mr D. Petrie and Professor C. Chilton. At the end of 1882, an injury which effectually lamed me, prevented the prosecution of further field work, but I continued to collect and work on the invertebrate fauna, especially the Crustacea.

The conviction early grew upon me that here in New Zealand was a field in which the accuracy of Darwin's views in certain directions could be put to the test. The way in which certain species of introduced animals and plants seemed to "run away," as it were, from their recognised specific characters, led to the expectation that new forms would spring up in this country under the altered conditions, and that we should here observe the "origin" of new species. I certainly was not alone in this half-expectation. It was somewhat generally, though vaguely, held. Examples were apparently numerous. Rabbits increased at an appalling rate, and appeared to be developing many coloured breeds; small birds-especially common sparrows, greenfinches, skylarks, etc.-multiplied prodigiously, and we were

on the lookout for all sorts of changes in colour, food, nesting habits, colours of eggs, and so on; trout grew so rapidly in the streams and lakes into which they were introduced as to belie all previously recorded experience. The same thing occurred among plants. Watercress-a plant of two to four feet in length in European waters-grew in some streams to a length of from twelve to fourteen feet, and with stems as thick as one's wrist; the common spear-thistle, which is from two to five feet high in Britain, formed in some districts vast impenetrable thickets six to seven feet in height; brambles, briars and other weeds took possession of whole districts, and threatened to choke out all other vegetation. It seemed indeed as if the laws of natural selection and the principle of the survival of the fittest had been temporarily suspended, and nature was running riot.

It is no wonder that all the younger naturalists in the country were almost inclined to think that perhaps we would here see the rise of new varieties, which would become "fixed," and would soon rank as "species," distinct from those from which they were descended. It may be that our ideas as to what constituted varietal and specific distinction were somewhat vague-in that respect we were not very different from the majority of those who used these terms in a somewhat loose manner-but there they were. Some such feeling was still in my mind as late as 1891, when I read a short paper before the Biological Section of the Australasian Association for the Advancement of Science at its Christchurch meeting, "On Some Aspects of Acclimatisation in New Zealand." The following sentences show the trend of my views at the time:

One of the most interesting points connected with the successful naturalisation of foreign species is the observation of the changes which they undergo in their altered conditions. Nearly all our introduced animals have been brought from lands where the struggle for existence is very keen, and where natural enemies abound. In their new home they have been set free from these old trammels, and the enemies have been left behind. Under such circumstances it is not surprising to find that sports in colour, which in Europe would be strictly eliminated as soon as they appeared, owing to their rendering their possessors too conspicuous to their enemies, are here preserved and tend to be reproduced.

I then went on to instance what occurs among hares, rabbits, sparrows and other birds, humble-bees, etc., both with regard to change of colour and of habits. My mind was evidently quite prepared to find such changes, though I had to admit that the evidence sought for was not forthcoming to any extent.

The subject continued to occupy my thoughts from time to time, but I was not able to devote much consecutive attention to it until 1915, when it seemed advisable to me to resume the thread of my