Lastly, there is Pittosporum obcordatum, the subject of the present memoir, which was discovered by Raoul at Akaroa about 1840, and which, after being lost sight of for more than sixty years, has been lately refound by Mr. R. H. Matthews at Kaitaia, a station six hundred miles to the north of the original locality.

Now, it is quite possible that careful investigation may prove that in some of the instances quoted above we are not dealing with a single species, but with two distinct though closely allied species having a different geographical range. In the case of Danthonia bromoides it seems very doubtful whether the Auckland Island plant is conspecific with the northern one. More probably we have here two species—one endemic in the Auckland Islands, the other, to which the name “bromoides” should be restricted, found only on the rocky coast-line of the North Island. Similarly it may be questioned if Bidwill's specimens of Urtica australis, said to have been collected near Wellington, are really identical with the typical form from the Auckland Islands They may be referable to another and much more common species, a supposition which would at once explain the fact that all recent attempts to find the true U. australis on the shores of Cook Strait have failed. As the existence of any species in widely separated localities is in itself a remarkable circumstance, it is not only natural, but highly desirable, that the evidence upon which such statements rest should be carefully examined and scrutinised from all points of view.

The recent discovery of Pittosporum obcordatum at Kaitaia has undoubtedly added another remarkable instance of discontinuous distribution to those already on record, and it is not at all surprising that attempts have been made to offer an explanation. As Raoul botanised at the Bay of Islands as well as at Akaroa, it has been suggested that his specimens may have been obtained in the first-mentioned locality, which is only fifty miles distant from Kaitaia. This view has been adopted in Laing and Blackwell's “Plants of New Zealand,” and in some newspaper writings of Dr. Cockayne. But it is by no means difficult to prove that the facts will not admit of this interpretation.

Pittosporum obcordatum was first described by Raoul in the “Annales des Sciences Naturelles” for 1844; but a fuller account, accompanied by a beautiful plate, was given in his “Choix de Plantes de la Nouvelle Zélande,” issued in 1846. In it Raoul gives the habitat as “Akaroa, in umbrosis humidisque nemoribus,” and he adds at the close of the description the remark (to which I invite special attention) “Florebat Decembre.” Since Raoul's time Akaroa has been repeatedly

visited by botanists or botanical collectors, such as Sir Julius Haast, Mr. Buchanan, Mr. T. Kirk, and many others. During these visits Pittosporum obcordatum was specially searched for, but always without success. Similarly, all attempts to find it in other localities in Canterbury or elsewhere in New Zealand met with uniform failure, until, in 1901, it was unexpectedly discovered at Kaitaia by Mr. R. H. Matthews. The assumption mentioned above that Raoul's specimens were probably gathered at the Bay of Islands and not at Akaroa no doubt explains a very puzzling case of discontinuous distribution, but the suggestion should scarcely have been made without some evidence in support of it. Raoul is well known to have been most accurate in any statements based upon his own personal observations. During the preparation of my “Flora of New Zealand” I have had occasion to check all the habitats assigned by him to New Zealand plants, and I cannot call to mind a single instance where he has given an erroneous locality or confused the habitats of any plant collected by himself. As a simple matter of justice to one of the pioneers in New Zealand botany, it appears desirable to examine all the known facts that bear upon the question.

Raoul arrived at the Bay of Islands on his first visit on the 11th July, 1840. He botanised at Kororareka (Russell), Paihia, and Waitangi, and left again on the 31st July, his stay being limited to twenty days. He observes that owing to the season of the year, and the abundant rains, he could only collect some well-known species. He arrived on a second visit on the 2nd December, 1841, remaining until the 13th of the same month, or eleven days. Lastly, in January, 1843, on his way back to Europe, he made a third call of a few days only. Altogether, he did not spend more than thirty-five or thirty-six days in the district. His visits to Akaroa were of much longer duration. On the first occasion he arrived on the 15th August, 1840, and remained until the 21st November, 1841, or over fifteen months, comprising, as he says, a complete series of the seasons. His second visit extended from the 26th January, 1842, until the 11th January, 1843, or very nearly twelve months. Altogether he resided for twenty-seven months at Akaroa. It is consequently not at all remarkable that the greater number of the plants mentioned in the “Choix” as being collected by himself have the habitat of Akaroa assigned to them.

The specimens figured by Raoul are in flower, and, as mentioned above, a note is appended to the description to the effect that the flowering month is December. If the specimens were collected at the Bay of Islands it must have been in December, 1841; if at Akaroa it may have been either December, 1840, or December, 1842. Now, it is well known that in the case of

species which range through the whole length of the colony there is a considerable difference between the times at which they flower in the North Island and South Island respectively, the same species blooming quite six weeks later in Canterbury than at the Bay of Islands. It appears to me that this difference in the flowering period supplies us with a simple means of deciding in which of the two localities Raoul's specimens were obtained. If they were gathered in December at the Bay of Islands, then the plant will also flower in that month at Kaitaia; if, on the other hand, we accept Raoul's statement that they were collected at Akaroa, it is obvious that the flowering season at Kaitaia will be about six weeks sooner, or about the end of October. I therefore applied to Mr. R. H. Matthews for information as to the time of flowering at Kaitaia. He has gone into the matter with considerable care, and informs me that the first fully expanded flowers were noticed on the 19th October. On the 27th October the plant was in full flower, continuing in that state through the early part of November, but entirely passing out of bloom before the end of the month. I think that it will be admitted that these observations of Mr. Matthews prove—(1) that Raoul could not have collected flowering specimens at the Bay of Islands, for the simple reason that the plant was not in flower at the time of his visits; and (2) that the flowering period at Akaroa would probably be in the month of December, thus harmonizing with Raoul's own statement. This evidence is, of course, of an indirect nature, but it appears to be quite sufficient to warrant us in accepting as correct Raoul's original habitat as published by him.

In the present state of our knowledge it is premature to speculate as to the reasons why Pittosporum obcordatum should apparently be confined to two localities so far apart as Kaitaia and Akaroa. The facts have yet to be collected which will explain such remarkable instances of discontinuous distribution. But it may be observed that systematic inquiry into the causes which have operated in such cases is of greater importance than would appear at first sight. If we could fully explain the discontinuous distribution of the plants mentioned at the beginning of this paper, we should know much of the past history of the flora and its gradual development, and we should be more fully acquainted with the vicissitudes of climate and the changes which have taken place in the physical conditions of the country.

One important consideration remains for discussion. Sir Joseph Hooker, in the “Flora NovÆ-ZealandiÆ” (vol. 1, p. 22), remarks with respect to Pittosporum obcordatum, “It presents some peculiarities of form and habit shared by several New Zealand plants of very different genera, which are not easily dis-