TflE GAWTflKON • INSTITUTE

OF

SCIENTIFIC RESEARCH.

CAWTHRON LECTURES

VOL. I.

1916-1919.

NELSON, NEW ZEALAND.

R. W. STILES AND CO., PRINTERS, ETC., \VAIMEA STREET.

1922.

EXCHANGE

OF

SCIENTIFIC RESEARCH.

CAWTHRON LECTURES

VOL. I.

1916-1919,

NELSON, NEW ZEALAND.

R. W, STILES AND CO,, PRINTERS, ETC., WAIMKA STREET.

1920,

a i

I H T //

mini

THOMAS CAWTHRON

Born at Camberwell, May 26, 1833
Died at Nelson, N.Z., Oct. 8, 1915

TRUSTEES:

Chairman: THE EIGHT REV. WILLIAM CHARLES SADLIER, M.A., D.D.
(Bishop of Nelson 1915.)

HENRY RICHARD DUNCAN. (Chairman of the Nelson Harbour Board
1915.)

HORATIO EVERETT. (Chairman of the Waimea County Council 1915.)
THOMAS ANDREW HEMMING FIELD. (M.P. for Nelson 1915.)
CHARLES JOHN HARLEY. (Mayor of Nelson 1915.)
WILLIAM ROUT. (1915.)

SECRETARY:

W. ROUT AND SONS, LTD., Nelson.

CAWTHRON COMMISSIONERS, 1916.

WILLIAM BLAXLAND BENHAM, M.A., D.Sc., F.R.S. (Professor of
Biology in the University of Otago.

LEONARD COCKAYNE, Ph.D., F.R.S. (engaged in 'Scientific Investiga-
tions for the Government of New Zealand).

THOMAS HILL EASTERFIELD, M.A., Ph.D., F.I.C. (Professor of
Chemistry in Victoria University College, Wellington).

PATRICK MARSHALL, D.Sc., F.G.S. (Professor of Geology in the
University of Otago.)

SIR JAMES GLENNY WILSON, K.B. President of the Board of Agri-
culture) .

FREDERICK PALLISER WORLEY, M.A., D.Sc., D.I.C. (Professor of
Chemistry in Auckland University College).

The Commissioners have continued in office as an Advisory Board.

STAFF, 1920:

Director: THOMAS H. EASTERFIELD, M.A., Ph.D., F.I.C. , Presi-
dent of the New Zealand Institute, Emeritus-Professor, Vic-
toria University College.

Agricultural Chemist: THEODORE RIGG, B.A., M.Sc.
Assistant Chemists: E. J. CHAMPTALOUP, MAXWELL YOUNG, F.C.S.
Chief Biologist and Entomologist: ROBIN J. TILLYARD, M.A., Sc.D.,
sometime Linnean McCleay Fellow in the University of Sydney.
Assistant Entomologist: ALFRED PHILPOTT.
Mycologist: KATHLEEN M. CURTIS, M.A., D.I.C., D.Sc.
Curator: WILLIAM C. DAVIES.
Assistant: H. HARRISON.

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CONTENTS.

PREFACE : The Cawthron Lecture.

LECTURE I. : "The Aims and Ideals of the Cawthron Institute," by
Professor T. H. Easterfield.

LECTURE II. : "Biology in Relation to Agriculture," by Professor
W.B. Benham.

LECTURE III. : "The Distribution of the Vegetation and Flora of
New Zealand," by Dr. L. Cockayne.

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PREFACE.
THE CAWTHRON LECTURE.

The Trustees resolved on May 4th, 1917, that there should be
an annual 'Scientific Lecture of a popular character in memory ot
Thomas Cawthron, the Founder of the Institute.

The first public announcement by the Trustees was made at
the inaugural lecture delivered by Professor Easterfield on July
10th, 1917, in the School of Music, Nelson. The Bishop of Nelson,
Chairman of the Trustees, presided over a large and representative
gathering. In addition to the Trustees, there were on the platform
the Mayor of Nelson (Mr W. Wallace Snodgrass), the Hon. A. T.
Mao-innity, M.L.C., the Principal of Nelson College (Mr H. L.
Fowler), the Principal of the Girls' College (Miss Lorimer) and the
Editor of the "Colonist" (Mr Hastings Braddell).

In his introductory remarks, the Chairman said he trusted that
the lecture of that evening would be the first of many scientific gath-
erings. He would not then say anything as to the generosity of Mr
Cuwthron in providing means for scientific research. The words of the
will were simple. The Trustees had very wide powers, so wide indeed
that they had induced many suggestions, some not at all wise, and
some useful. It wa's, however, a case of what they were able to
do, not what they would like to do. As to several of Mr. Caw-
thron's proposed benefactions, which had he lived he would un-
doubtedly have carried out, the Trustees had had to take the opinion
of the Court, and very much against their personal wishes some had
io be dropped. The speaker then detailed the setting up of a
Commission of scientific men, who met in Nelson, and whose
deliberations led to the evolution of the scheme which the Trustees
had now in hand. The central idea was to do one thing well and
not spread effort over too large a field and thereby lose effectiveness.
The one thing they had adhered to strictly was the in-
vestigation of biological and chemical problems bearing
on the agricultural industries of New Zealand. It was
not intended to enter upon all of these subjects at once, nor to
go in for any great building : they were looking for brains rather
than for bricks. One thing at a time and that done well waft
+heir aim, and the expressed wishes of the Founder of the Institute
would ever be kept in view. There were two dangers which the
Trustees were specially anxious to avoid in order that the spirit of
those wishes should be given effect to, and those dangers were com-
mercialism and officialdom, Every care would be taken to avoid

8
red tape and to see that the work of the Institute was not

ed by eocimercialisni in spirit. He then introduced Professor
Easterfield as first lecturer on behalf of the Institute.

At the conclusion of the lecture, the Mayor (Mr W. Wallace
Snodgrase) moved that a vote of thanks be accorded to the
lecturer, and said the address had been all too short, and that he
was sure all those present would have been glad if, the
Professor had continued longer. He expressed the opinion
that the Professor had given a very true estimate of the feelings
which had actuated Mr. Cawthron in making the grand bequest he
had to Nelson. He (the Mayor) had been an intimate friend of
the late Mr. Cawthron, and knew that he had a great heart, which
was specially tender towards the people of his own town. The
Mayor complimented the Trustees upon selecting Professor Easter-
field to give the inaugural' address.

The Hon. A. T. Maginnity, who seconded the motion, said
that a kindly thought must be in every mind for the gentleman who
had conferred so great a benefit upon the community in which he
had spent the greater part of his life, and this benefit would descend
to their children's children.

The motion was carried by acclamation, and after Professor
Easterfield had briefly replied, the meeting closed with the
National Anthem.

LECTURE I.
THE AIMS AND IDEALS OF THE CAWTHRON INSTITUTE.

By THOMAS.HILL EASTERFIELD, M.A., PH.D., F.I.C., F.C.S.,
Professor of Chemistry, Victoria' College, Wellington.

Let me express to you my deep appreciation of the honour which
has been conferred upon me by the Cawthron Trustees in inviting me
to make the first public statement as to the manner in which it is
proposed 10 carry out the wishes of the late Thomas Cawthron, in
whose memory this lectureship is founded.

For years I have held the view that in New Zealand there is great
need of an institution the special object of which shall be the carrying
out of scientific investigations, but I scarcely expected to live to see
the fulfilment of this ideal. I therefore rejoice to announce that by
the munificent bequest of a great benefactor such an institution will
be erected in your city. It is to be called the Cawthron Institute of
Scientific Research. All truly great men are lovers of the country
of their birth, but it is peculiarly characteristic of the British to
develop an equal love for the countries which they colonise. Thomas
Cawthron was an outstanding example of such great men. Coming
to New Zealand as a weakly boy, he eventually became
a strong man and developed an equally strong character.
Frugal in his habits and shrewd in business, he was very
liberal in regard to all matters which make for the
public welfare. This city is rich in evidence of the catholicity
of his civic ideals. The Cawthron Park, with seven thousand acres of
mountain and forest, the Nelson Institute and Library Building, the
School of Music, the imposing flight of Cathedral Steps, need only
be mentioned as objects of his generous care during his lifetime. By
his will an estate of the value of £240,000 has been left for the
material and intellectual advancement of the city and district which
lie so dearly loved.

In this time of stress our natural desire is "to honour those who are
risking their all in fighting on behalf of the ideals for which the
British Empire stands ; but let us not forget that patriotism may be
of many kinds, and that to live for one's own country may be a still
harder task than to die for it. To every patriot a meed of praise is
due. The work of the Cawthron Institute will, we trust, be a per-
petual memorial of the patriotism of its founder. I have already
stated that the Trustees have decided that the Institute shall be
primarily an Institution for Scientific Research. They recognise that
the value of research work has been too little appreciated throughout
our Empire, and that this defect has greatly retarded national
efficiency. It is indeed surprising how little the general public is
aware of the debt which it owes to the scientific workers of the past,
and how little it appreciates the extent to which the future of our
Empire may depend upon the organisation of. our resources and the
submitting of them to systematic scientific investigation.

10

Objection may be raised that in concentrating- on scientific research
a tribute is being paid to. the success of German methods, for it is
doubtful if any country has benefited so much and in so many direc-
tions from the application of research methods as modern Germany
has done. Let me remind you of that old Latin proverb which
teaches us the wisdom of learning from the enemy. True wisdom
and foresight demand that not only shall we learn from our enemies,
but that by proper attention to organisation and detail we shall
surpass our opponents in the realisation of the national value of
science. In speaking of scientific research to an audience consisting
largely of laymen, I know that many among you will scarcely
understand what is meant by this expression ; let me therefore draw
your attention to a few concrete cases so that you may clearly
appreciate the utility and value of scientific research.

And here I pray you not to confound utility with money-making
or money-producing. By utility I understand anything which makes
for good — which makes life sweeter — which develops an appreciation
of art, music, or literature, or which tends towards the raising of
public ideals. The value of all education must eventually be judged
ia terms of utility. Nearly all of you are interested in agriculture.
1 therefore mention first of all the work of Liebig, who devoted his
great chemical knowledge to researches on the ashes of plants and to
the chemistry of animal and plant nutrition, and thus laid the very
foundation of modern agricultural chemistry. It is true that many
of his conclusions were wrong, but he demonstrated beyond doubt the
value of potash and phosphoric acid as fertilisers ; and the continua-
tion of his work has undoubtedly revolutionised agriculture and been
of the greatest value in increasing the world's supply of foodstuffs.
Following closely on Liebig we have the epoch-making work of
Gilbert and Lawes, whose lives were practically devoted to the study
of the scientific aspects of wheat- growing. By their bequest the
estate at Rothamsted, on which for so many years the experiments
were carried out, is secured for the British people as an agricultural
experimental station.

Let us turn to the oft-told tale of the coal tar industry. Owing
largely to the efforts of Prince Albert Victor, Lyon Playfair, and Sir
James Clarke, a lioyal College of Chemistry was established in London
in the late 'forties. In it were trained Mansfield, the first chemist
to prepare benzene and toluene on a commercial scale, and William
Henry Perkin, who, at the ago of seventeen, discovered mauve, the
first of the so-called aniline dyes. Hundreds, if not thousands, of
investigations have arisen upon the foundation laid by these dis-
coverers and by their teacher, Professor Hoffmann, and coal tar colours
have now almost replaced the vegetable dye stuffs. Many of
the substances obtained in these coal tar researches have proved to be
o" the greatest value in medical practice. I need only allude to such
products as carbolic acid, cresol, antipyrin, aspirin, and phenacetin.

Upon the foundations well and truly laid, by Dav,y ar^l. Faraday
has been raised the magnificent edifice of modern electro-cnemistry.

11

By electro-chemical means we now obtain calcium carbide, carborun-
dum, artificial graphite, caustic potash, nitrogenous fertilisers, and
nitrates for the manufacture of explosives. Indeed, electro-chemistry
piomises to revolutionise the manufacture of nearly all chemical pro-
ducts.

Michael Faraday's researches on the liquefaction of gases, extended
notably by Andrews of Belfast, by Pictet, Cailletet, Joule, and Play-
fair, IJewar, Olzewski, and Kammerlink Onnes, led to the commercial
practice of gas liquefaction. To New Zealanders the history of gas
liquefaction should be of great interest, for our export trade is based
upon efficient cold storage, which in turn depends for its success upon
the economic liquefaction of ammonia and carbonic anhydride.
Faraday's researches in electro-magnetics paved the way to the
invention of the electric telegraph and telephone and to the produc-
tion and distribution of electric power. Clarke-Maxwell's investiga-
tions on oscillatory discharges first made known the probable
existence of electric waves. Their existence was shown to be a
reality by Hertz, after which wireless telegraphy became a com-
mercial success in the hands of Marconi.

Not less remarkable are Pasteur's researches on micro-organisms.
Their results have been far-reaching. The application of aseptic
methods in surgery and the use of antitoxins in the treatment of
disease, though not due to Pasteur, are certainly based upon his

discoveries.

The investigations of Patrick Manson and Ronald Ross proved that
a special mosquito Anopheles is the carrier of malarial fever; and
the successful completion of the Panama Canal became possible only
after a decisive victory had been gained by Dr. W. C. Gorgas over
{mother type of mosquito Stegomyia fasciata found by Charles
Finlay to be the agent of infection in cases of yellow fever.

Researches on the radiating power of the rare earths led to the
invention of the Welsbach mantle, which, with a consumption of one-
half of the quantity of gas, gives at least four times the quantity of
light yielded by the old flat flame gas burner. Parallel with this
reduction in the cost of gas lighting must be placed the development
of metallic filament lamps, which have rendered a like service to
electric lighting.

There is indeed no class of industry and no art or profession which
has not benefited by the researches of scientific men ; nevertheless, it
must be admitted that the British have been slow to recognise the
national importance of science and the benefit to be derived from the
organised application of science to industry. The value to the
Enrnire at which the trained investigator is officially assessed is, I
think, fairly well represented by the action of the War Office, which
in the early stages of the war, advertised for skilled chemists at a
salary of £2 Os. 6d. a week,

•

ft

It is undoubtedly true that the phenomenal extension of German
industries from 1870 onwards has been largely, though not entirely,
due to the alertness with which the German people have recognised
the importance of both pure and applied science. A French savant
dealing with this question has recently stated that in proportion to
population Germany and Switzerland have six times as many trained
chemists as have France and Great Britain. Assuming that the
mental calibre of the inhabitants is approximately equal, the
probability of a large output of scientific discovery is obviously on
the side of the countries with the largest proportion of trained scien-
tific workers. An examination of the scientific literature, pure and
applied, will convince anyone of the accuracy of this contention.

What I have said will, I trust, convince you of the far-sightedness
and wisdom of the Trustees in deciding that the Cawthron Institute
shall be a home for scientific research ; but I will forestall three ques-
tions which may perhaps have suggested themselves to you : —

I. Is New Zealand a country sufficiently advanced to furnish men

who can be trained to carry out high-class research work ?
To this I unhesitatingly say "Yes." Let me remind you that the
secondary school of this city — Nelson College — has produced Sir
Ernest Rutherford, Brigadier-General Chaytor, and Professors
Evans and Worley ; and that other secondary schools in New Zealand
can point to a number of former students who, after further training
in the University Colleges, now hold high scientific positions in
Great Britain, India, Australia, and America. Let me add that
your fellow-townsman Lieutenant Athol Hudson, the brilliant athlete
whose loss in action we so deeply deplore, had already shown by his
manipulative skill, his scientific attitude of mind, and his earnestness
of purpose, that as an investigator a great future was before him.

II. Are there actual scientific problems awaiting solution in this
country ?

(a) In agriculture alone there are many problems waiting to be
investigated, though the researches of the scientific staff of the De-
partment of Agriculture have done much work of very great value.
One of the most recent departmental investigations has dealt with
the cause of bush sickness, which rendered approximately one million
acres of the North Island unfit for the rearing of stock. Mr. Aston
has demonstrated very clearly that this is a deficiency disease,
associated with shortage of iron in the grass growing in a soil poor
in the same element. Further experiments by Dr. Reakes show that
when this iron is suitably provided the diseased animals recover.
Assuming that this discovery can be generally applied and that a
"research tax" ( ? !) of 3d. per acre were levied upon the bush sickness
area, for improved value resulting directly from these researches, it
would yield an income as large as that which will be available
for the Cawthron Institute.

(b) The fruit industry, which has risen so rapidly in the Nelson
district, and which if suitably fostered may become one of our
greatest national assets, may, on the other hand, be stamped out if

13

means are not discovered for combating the natural enemies of the
fruit tree. Forty years ago blights are said to
have been practically unknown in this district; even
the peach tree was in those days free from attack.
At the present day we hear constant complaints of blights and insect
pests, of bitter pit, black spot, aphis, and codlin moth. I do not
doubt that all these plagues are capable of scientific control, and the
workers at the Institute will no doubt show us step by step how each
of these troubles is to be dealt with. Some of these investigations
will require to be very lengthy, involving, as they certainly will, a
study of the life history of the various pests and of the conditions
which are most and least favourable to their development. "Good
bread needs baking," and it is only by a very careful examination of
each problem, in consultation with the practical men engaged in the
industry, that improvements, such as we all desire, can be effected.
It is perhaps worth while to point out that a comparatively small
improvement in the general producing value of the land in the Nelson
district would represent an annual sum exceeding the whole capital
value of the Cawthron Bequest ; and if only one investigation out of
twenty carried out in the Institute proved to be of direct economic
value the expenditure on the researches would be more than justified.

(c) The flax industry, the third largest of the New Zealand export
trades, will benefit greatly by the applications of scientific method.
Very little work of value has been published about Phormium tenax
since Hector's valuable report in 1889 based chiefly on the reports
of the Commissioners in 1871. Three tons of refuse are produced
for every ton of fibre, and no use is made of this refuse, though it
is known to have a considerable manurial value. My experiments
have convinced me that the substance may become a profitable
source of alcohol, of mill fuel, and of potassic fertiliser. Experi-
ments are badly needed upon flax cultivation under rigorously con-
trolled conditions with the object of producing disease-resistant
strains, more rapid development, larger leaves, increased quantity
and better quality of fibre. Such experiments will certainly be
attended with great difficulties, but in view of the success which has
followed similar investigations in the case of wheat, of beetroot, and
of sugar cane, there is no doubt that the researches should be at
once initiated.

(d) Much experimental work is needed in connection with our
forests; indeed, according to that noted forester, Mr. D. E.
Hutching, "scientific forestry in New Zealand has yet to begin."*
Timber shortage is almost world-wide; it is pressing in New Zea-
land, and will in a few years become acute. With a sane forest
policy this country would have abundance of timber for its own
needs and for a large export trade. This trade would support a
large forest population and Avould lead to the conversion of many
inferior beech forests into areas of high-class timber and to the
reahorestation of districts in which the forest has been thouo-ht-
lessiy and disastrously .destroyed. There are apparently few
systematic records of the rates at which our native trees grow

*A Discussion of Australian Forestry. Perth, 1916, p. 389.

14

under forest conditions in different localities and on different soils.
There is too wide a conviction, based upon insufficient evidence,
that it can never pay to grow native trees for timber, and that the
only imported trees worth planting are Pinus insignis (radiata) and
Eucalyptus globulus. Australasia is without a well-appointed
scientific arboretum, and if the Cawthron Trustees will establish
such a park for the study of forest problems they will be initiating
a great and much-needed educational work and will earn the thanks
of all tree lovers.

III. Should only researches of obvious economic importance be
carried out at the Institute?

I think not. Every large economic research involves the collection
of so many purely scientific data that to confine attention to
researches which we can see to be useful would, in the end, lead to
disaster. The instances already mentioned illustrate clearly how
very generally investigations in pure science form the basis upon
which industrial development becomes possible.

Let me now outline to you the plan which the Commissioners have
recommended and which the Trustees propose to follow. First of all
a site has been secured. This is the Annesbrook Estate of twenty
acres, bounded by the Rocks road, the Waimea main road, and the
railway; it is nicely wooded, well-drained and partly in orchard. The
site overlooks Tasman Bay and the Waimea Plains, and is, I consider,
an ideal situation, whether from the aesthetic or practical standpoint.

The Institute will contain well equipped chemical and biological
laboratories, suitable offices, and a fine library, rich in scientific
journals and memoirs containing the original researches of investi-
gators in all parts of the world. By exchanging the bulletins from
the Cawthron Institute with those of other institutions, the library
will be further, enriched ; these bulletins will form a valuable record
of investigations carried out in the Institute.

Included in the Institute will be a Technical Museum, this being
wisely specified in Mr. Cawthron 's will. The museum will illustrate
in an interesting and striking manner the value of science to agri-
culture in its widest sense, to mining, forestry, and the secondary
industries. A further important function will be to demonstrate the
results of the investigations carried out by the members of the staff.

The researches will in the first instance bear chiefly upon agricul-
tural and in particular upon fruit-growing problems.

A Director will be appointed who should be a man of high
scientific attainment and administrative ability. He will be respon-
sible for the organisation of the researches to be carried out by a
staff of trained investigators. The plan of work will be decided by the
Director in consultation with a Board of the most eminent scientific
men in New Zealand. The Trustees have requested the Cawthron
Commissioners to act for the present as an advisory board. The

15

workers in the Institute will not consist of boys and girls who have
just left a secondary school ; for without a higher training such stu-
dents would be of little use in a research institution, and would
seriously interfere with the work of the staff. On the other hand,
students who have already received efficient training in the scientific
departments of our University Colleges would benefit greatly by
working in the Institute, and would render material assistance to
the investigators with whom they would collaborate. They would
obtain a deeper knowledge which would be of great help in later life,
whether they became scientific experts, agriculturalists, teachers, or
professional men. It is therefore proposed to allow any student
who can produce evidence of efficient scientific training to work in
the Institute, the special work of each student being allotted to him
by the Director, after consultation with the members of the scientific
staff.

In order to attract to the Institute the most brilliant students from
all over New Zealand, it is proposed to establish a series of scholar-
ships and fellowships, commencing with a Cawthron Minor Scholar-
ship* of the value of £100 per annum, to be awarded annually to the
most able candidate in science in the University Entrance Scholarship
Examination, on conditions which I need not here detail. Preference
will be given ceteris paribus to candidates from Nelson and Marl-
borough districts. The Scholarship will be tenable for three or
four years at any one of the University Colleges.

The Cawthron Foundation 'Scholarships will be of higher value,
and will attract the best science graduates of the University, men or
women who have already shown high promise of carrying out research
work.

Cawthron Fellowships will also be established. The holding
of these Fellowships will, I doubt not, be regarded as one of the
highest scientific honours in New Zealand. No doubt the Fellows
will in general be selected from those foundation scholars who have
carried out work of such value that it is deemed advisable to retain
their services for a further period of one or two years.

We may reasonably expect that as the value of the work of the
Institute becomes known and appreciated, private benefactors will
contribute additional endowments to the general fund of
the Institute, or for special researches, or in the
form of scholarships or fellowships. Should any associa-
tion, society, or private firm desire to have technical researches of a
special type carried out in the Institute the Trustees will be prepared
to allow this to be done, the parties interested bearing the cost of
the investigations, including the salary of a Fellow, who will be
appointed by the Trustees in consultation with the Advisory Board.
A similar scheme has given satisfaction in some American institutions.

*0wing to a decision of the Supreme Court, it has been found necessary to
abolish the Minor Scholarship scheme.

16

It is seldom wise to assume the role of a seer, but so certain
am I of the wisdom of the course upon which the Trustees are
embarking that I foretell a brilliant future for this Institute. The
problems solved in it will lead to results of the greatest value to this
city, to the Dominion, and to the human race. Workers who have
carried out these researches are destined to become scientific leaders
with a world-wide reputation, and the Institute itself to be a centre
of light, learning, and culture, honoured throughout the civilised
world, and a lasting tribute to the memory of Thomas Cawthron.

R. W. Stiles & Co., Printers, Waimea Street, Nelson.— 23562

LECTURE II.
BIOLOGY IN RELATION TO AGRICULTURE.

By W. B. BENHAM, M.A., D.Sc , F.R.S., F.Z.S. (Professor of Biology at the
University of Otago).

Delivered in the School of Music, Nelson, on May 30th, 1918.

I have to thank the Cawthron ,Trustees for doing
me the honour of inviting me to deliver the annual Cawthron Lecture
this evening. I esteem it a high compliment, the more so as we
hope that the Cawthron Lecture will continue to be an annual event
ir Nelson, and that the lecturer will always be chosen as being of
some note in his special profession.

In the Old Country there are many such foundations
providing an annual .lecture in1 order to perpetuate the
memory of a man who has by his generosity or his
researches aided or advanced science or literature, and men of note
in all walks of life — literary men, scientific men, statesmen, church-
men, and others — are invited to do honour to his memory. I recall
the Hunterian Lecture at the Royal College of Surgeons in memory
of that most distinguished anatomist, John Hunter, who in the
Eighteenth Century commenced the formation of that great museum
of comparative anatomy; the Hibbert Lectures; the Gifford Lectures,
at which many notable men have spoken ; the Romanest and the
Royle at Oxford ; the Huxley Lectures, and a dozen others.

Those of us who are interested in the future of the Cawthron
Institute for Scientific Reasearch hope that, within the limits set
by our geographical situation, eminent men — not scientists only —
will be invited to commemorate the benefactions of the late Mr
Thomas Cawthron.

The citizens of Nelson should be, and I have no doubt are, proud
of having had dwelling among them so generous and yet so modest a
man as Mr Cawthron. Although, as I understand, he lived a
retired and quiet life, taking no share in public matters, yet he did
many a kindly action in the quietest way, helping financially and
otherwise those of whose difficulties or distress he heard ; and this he
did in so unobtrusive a fashion that one may almost say that his left
hand knew not what his right hand gave.

But, as we all know, he also gave large sums of money towards the
improvement and beautificatipn of this city. To him you owe the
fine organ in this hall ; to him the handsome steps which form so
grand an approach to your Cathedral — itself to be replaced some day,
by an edifice more in keeping with the progress of the city. You

tThus the Right Hon. H. Asquith, M.P., is to give the Romanes Lecture in
1918, on "Some Aspects of the Victorian Age" — a leading statesman is to com-
memorate the work of Romanes, who was a distinguished evolutionist.

owe to him, too, a large monetary gift for a new Hospital, and the
Cawthron Park. And, as you are aware, Mr Cawthron had con-
templated several other improvements, which unfortunately had
to be left unfulfilled owing to his death in 1915.

Nelson is indeed fortunate in having had as a citizen a man who
used his wealth to such good purpose and with such large ideals, for
many men who have accumulated a fortune by business in the
Dominion retire to Great Britain and spend it there, instead of return-
ing the money in the form of benefactions to the people from whom
and amongst whom they have derived it. All praise is due, and all
honour, to the late Mr Thomas Cawthron, both for what he did and
for what he proposed to do for this city.

These varied benefactions and improvements are sufficient to render
Mr Cawthron's name memorable in Nelson city and provincial dis-
trict ; but in the Cawthron Besearch Institute there will be a monu-
ment to him that will bring his name constantly before scientific
agriculturists all the world over. We hope that in time when the
Institute • is established it will become the home of important
discoveries in aid of agriculture, and especially of orchardry. If
the ideals of the Commission, which the Trustees selected to advise
them in the matter,, are carried out, we may look forward to the time
when the Cawthron Institute will take rank with the older establish-
ments like the Rothamsted Experimental Farm in England, and with
many American institutes for research ; that it will become the centre
of research in New Zealand, and will ultimately attract to it men of
science from all parts of the Dominion and from Australia, and even
in the years to come from further afield. That will, however, not
be for many years ; the Institute has yet to be organised, to be
provided with a staff, who will have to feel their way amongst
many and difficult problems.

What I particularly want to impress upon you is that research is
not a matter of a month or two, nor of a year; in order that it may
yield results of permanent value the whole scheme for research must
be most carefully planned and patiently carried on by efficient and
scientifically trained men. In the first Cawthron Lecture, "On the
Aims and Ideals of the Cawthron Institute," Professor Easterfield
set out fully the benefits that research would confer not only upon this
district, but on the Dominion.

So far as I can gather from the press report of that lecture, Pro-
fessor Easterfield dealt in general terms with the valuable results
that have accrued from the application of science, especially of
chemistry, to industry, and I propose to-night to deal with a
restricted field and attempt to interest you in an account of some
little fragments of help that research in biology has conferred on
certain agricultural problems.

I find that I must confine myself to a very limited field, and shall
discuss mainly the organisms which by their activity serve to enrich
the soil and make it suitable for the growth of plants, and later will
refer to the subject of diseases which attack fruit tree*!

3, i

THE BIOLOGY OF THE SOIL.

A plant derives its food partly from the air by means of its leaves
ana partly from tne soil by means of its roots ; and the whole process
depends on sunlight, which aftords the energy necessary ior the manu-
iacture of sugar Dy the green leaves, to which mineral salts from the
soil are carried up the stem from the roots. Here in the leaves new
chemical changes occur, raising the sugar a step higher in chemical
complexity by the addition to it of nitrogen, and the substance thus
formed travels away from the leaves to all parts of the plant in order
to undergo further chemical elaboration step by step, till new living
matter, protoplasm, has been built up. The plant is, indeed, a
creative agent — it can build up living substance from wholly
inorganic or mineral matter ; in other words, from the dust and from
the air ,it can raise inorganic matter to organic matter.

It is the business of the horticulturist and the agriculturist to
provide his plants with abundant and suitable food material. He is
not content with that quantity of mineral food that is already in
the soil, for that sooner or later would be exhausted under intensive
cultivation.

It is at present impossible to alter the amount of food material
obtained from the air, but it has been found possible to improve and
increase the food material contained in the soil, effectively and eco-
nomically, and the knowledge that we have of this principle of
manuring has largely been brought about by experiments carried out
during many years by Lawes and Gilbert and their successors at the
experimental farm at Rothamsted, in Hertfordshire. Last year
Professor Easterfield dealt with the chemical aspect of this question.
To-night I propose to discuss the biological aspect, for biology has
played a considerable part in recent years in advancing our knowledge
of the chemical processes going on in the soil, whereby the nitro-
genous material of manure is rendered available to the plant.

I say "available" for it is not every mineral salt that is useful.
The plant can select from the mixture we call the soil just what it
needs ; but it can only take it if it be in a special state of chemical
combination.

The soil consists of irregular particles, varying in size and shape
and material in different kinds of soil — fine in clays, coarser in sandy
soils — and these particles consist of minerals of different sorts, includ-
ing the nutritive or food material of plants. This nutritive material
consists of the phosphates, sulphates, nitrates of such bases as
potash, lime, and magnesia. With these mineral materials there is
always more or less organic matter derived from the decay of plants
and animals that live in the soil. And in order that a soil may be
"rich" it must contain a proportion of this organic matter or
"humus," the material that is dark in colour, and supplies the
"open" character of soils. The soil particles are separated from one
another by smaller and larger spaces containing air, which is as
necessary for the health of the roots as for that part of the plant above
ground. These spaces also contain water, which forms from 15-30
per cent, of the weight of the soil. This water is mainly distributed
in very thin films over the solids, though of course after rain the

spaces may be filled with water ; and unless the ground be properly
drained the soil becomes waterlogged, and it is common knowledge
to all of you that this is quite unfavourable for agricultural 01
horticultural purposes. The aeration or ventilation of the soil is to
a great extent provided by the burrowings of earthworms, insect
grubs, and other animals.

THE WORK OF EARTHWORMS.

I daresay some of you are acquainted with a work entitled "The
Formation of Vegetable Mould by Earthworms," written by Charles
Darwin and published as long ago as 1881. In that work he showed
the great importance of these lowly animals to the agriculturist both
in ventilating the soil and in improving its properties. Earthworms
swallow small quantities of soil in order to obtain decayed vegetable
matter occurring therein. This they do while making their burrows,
although they also feed en young fresh leaves. The small particles
are ground still smaller in the gizzard, which is like that of a fowl.

("Reference was then made to the mode of action of earthworms ;
the formation and extent of their burrows ; to the astonishing num-
bers per acre, and the surprising amount of ''vegetable mould"
brought up by them to the surface annually, as estimated by Darwin
in England, by Urquhartt, and by 'Smith:}: in New Zealand.]

This vegetable mould or "humus" differs from the subsoil in its
fine grain and dark colour, in its freedom from stones of a size
greater than can pass through the worm's digestive tract. It has
undergone certain changes while passing through the worm's body
and owes its dark colour to the presence of much organic matter,
that is, of decaying or decayed vegetable matter, and it contains
therefore an abundance of nitrogenous compounds. This "humus"
is alkaline, and affords energy to numerous micro-organisms which
convert it into simpler substances appropriate for plant nutrition. It
also improves the physical character of the soil.

THE IMPORTANCE OF NITROGEN.

I want now to direct your attention to the importance of nitrogen,
a gas which forms a considerable part of the air we breathe, but
which plants can take from the soil only in the form of nitrates. The
life both of animals and plants depends on the stock of nitrogen re-
tained in the soil in the form of nitrates. The total nitrogen in
arable soils is about 0.15 per cent ; higher in some soils than in others.
But the amount present as ammonia is only .0001 per cent., that is,
about one part in a million in arable soils, and about ten times as
much in heavily dunged soils. No soil constituents fluctuate more
than the nitrogenous. Plants remove them, rain drains them away.

tUrquhart, A. T., "On the Habits of Earthworms in N.Z." Trans. N.Z. Inst.,
vol. xvi., p. 266. 1884; and "On the Work of Earthworms," ibid, vol. xix., p.
119. 1887.

JSmith, W. W., "Notes on N.Z. Earthworms." Trans. N.Z. Inst., vol. xix.,
p. 123. 1887. (The names given by him to our earthworms are qi:.ite wrong, and
are corrected in next article). Smith, W. W., "Further Notes on N.Z. Earth-
worms," ibid, vol. xxv., p. Ill, 1893; and vol. xxvi., p. 155, 1894.

In pastures flocks are feeding all the summer and furnish us with
nitrogen in the form of milk, cheese and meat ; yet the soil of these
natural pastures still contains quantities of nitrogen greater than ary
to be found in ploughed and copiously manured land. Crops of all
kinds remove from the soil more nitrogen than the manure supplies.

It is evident that there must be some recuperating agency, or the
stock of nitrogen would long ago have disappeared from the old
countries. Experiments show that soil gains nitrogen if it is
allowed to remain undisturbed or in natural conditions.

Whence comes this nitrogen ? It can only come in the last place
from the inexhaustible reservoir of the atmosphere.

The great German chemist Liebig, who contributed so much to our
knowledge of the chemistry of plants, supposed that they obtain
their supply of nitrogen directly and in its elemental form irom the
air. but about the same time a French chemist, Boussingault,
showed by experiments conducted during some twenty years that
plants are quite unable to do this, but must obtain it from some
mineral in tne soil. The discovery of this fact was a step of great
importance in plant physiology.

How, then, is this nitrogen fixed ? In what form does it
occur in the soil? And how is it made available for the plant?
In the farmer's manure heap are found countless minute
organisms, fungi or moulds and bacteria, which are feeding
on the vegetable substance which makes up the manure. By the
action of these a fermentation is set up ; in other words, the manure
becomes rotted. It owes its warmth to this chemical action, and
as we know the gas ammonia is given off in abundance. This
ammonia is one of the results of the decomposition of the vegetable
matter, and is wholly the work of these minute bacteria, and all
nitrogenous manure except nitrate of soda, all such substances
as guano, dung, wool-waste, bone-meal, sulphate of ammonia,
have to undergo the action of bacteria before the products
are of any use to the plants. The result of the action, then,
is the formation of ammonia. But in this form the nitrogen
is still useless. The gas enters the soil, and is here converted
by chemical combination into ammonium carbonate. But still
further changes have to take place before it is of use to the plant.
Now scientific agriculturists are generally agreed that the most im-
portant food materials of the plant are nitrates ; that is, nitric acid
in combination with mineral bases, and for the moment we may speak
of nitric acid as the important thing. "If the soil were utterly
devoid of this substance it would be incapable of yielding the barest
pretence of a crop of any sort, even if the soil be in other respects of
the most superfine texture, however favourably it might be situated,
however well drained, tilled and supplied with the purely mineral
ingredients of plant food."t Yet nitric acid occurs in only very
minute quantities in the soil.

tFrankland, P. F., "Our Secret Friends and Foes." (Romance of Science
Series, S.P.C.K.).

SOIL BACTERIA.:

The question then is — How is the ammonia converted into nitric
acid? it was not till 1877 that two French chemists showed by a
very simple experiment that the power of soils to convert nitrogen,
that is, the ammonia of the manure, into nitric acid was the work of
some kind of living thing or organism.

Muntz and Schloessing* allowed dilute sewage to trickle down
through a vessel packed with chalk, i.e., carbonate of lime. They
found that no change took place for the first fortnight or three weeks,
but then suddenly the fluid that accumulated at the bottom of the vesse]
was found to contain nitrate of lime, i.e., nitric acid had been formed.
If this process of nitrification was due to some chemical or physical
procedure it should set in at once. Why then was this delay ?
They argued that it could only be because the process was biological ;
that is, was due to some living organism, and the period of delay was
needed for the multiplication of this organism.

The theory was tested by adding chloroform to the soil. This, of
course, would put a stop to the action of any organisms. The pro-
cess at once ceased. -But on the replacement of the chloroform by
air or oxygen the process set in again. That is, the organisms had
been temporarily numbed, but had recovered in the air. Although
Muntz did not follow this particular aspect of the matter any further,
others did, and there, arose a new branch of science, that of "Soil
Bacteriology."

Amongst those who continued to work at this problem was notably
Warington, who worked many years at Rothamsted. After a series
of experiments he obtained a culture which was able to turn
the ammonia into nitrous acid. This was in 1879. But he recog-
nised that he must go further, for nitrous acid only combines to form
nitrites, which are quite useless to plants. After two more years
of work he obtained a further culture which was able to convert the
nitrous acid into nitric acid. This was an important step, and
perhaps you might think that it sufficed. So perhaps it would for
the practical man, but the scientific man wants to know how these
two changes are brought about. What is there in the liquids that
bring about these chemical changes ? Muntz had proved that some
organism was concerned in the process, and people now set about to
try and find what that organism might be. The credit of discover-
ing a specific organism in these cultures is due to Dr. Percy
Frankland, of the Royal College of Science in London. t He in 1890
succeeded in isolating a special bacterium, and his discovery

JDr. Russell's useful work, "Soil Conditions and Plant Growth" (Longmans,
Green, and Co., 1917), contains an admirable historical account of all that
relates to the soil.

*Schloessing and Muntz, "Sur la nitrification par les ferments organises "
Comptes Rendues. 1877.
tFrankland, loc cit, p. 87.

was shortly afterwards confirmed by others, especially by Wino-
gradsky,:}: who was then working in Pasteur's laboratory in
ijaris. The bacterium thus isolated and bred by Frankland had so
long eluded detection because it does not and cannot feed and grow
upon the materials usually employed in bacteriological cultures,
broth, jelly, etc., that is on organic stuff. Winogradsky discovered
that it will grow and flourish only on mineral matter. A most
astounding discovery at that time, but having found out this, he had
no difficulty in keeping the bacterium alive and multiplying for
years. He was able to prove that his little organism played only a
part in the history. It converts ammonia into nitrous acid. It
was the organism that occurred in Warington's first culture. Having
started the work, others profited by this discovery, and Warington
with this hint found in 1891 in his second culture the second organ-
ism or link in the chain, namely the organism that converts the
nitrous arid into nitric acid.* And thus at last the whole process of
nitrification of the soil, that is the continued supply of nitrates,
became intelligible. It is due to two distinct forms of bacteria which
occur in enormous numbers in the soil, anything from ten millions
to forty millions per gramme of soil. So that in spite of the constant
removal of the nitrates from the soil by plants bacteria are as
constantly producing them.

Yet these facts which to-day are known to every elementary student
of botany took many years of continuous, arduous, patient, and
ingenious research, carried on by several people, working at first
independently : — Muntz 1877, Frankland 1890, Warington 1891 ; a
total of fifteen years of work, Warington himself devoting, on and
off amidst other work, thirteen years to the elucidation of this
problem.

It must be borne in mind that this long piece of research work,
which is of as great importance to biology as to agriculture, was
carried out by men who were working from a purely scientific interest
in the problem. They found sufficient reward in the gradual over-
coming of the successive difficulties and in pushing forward the
discoveries step by step to a solution.

Although we owe the commencement of our knowledge of these
bacteria to the experiments and observations of Englishmen, it is
only fair to mention that others put the matter on a firm footing by
confirming the experiments under varied conditions and extending
the work. For instance, Winogradsky, who did an immense amount
of work later, and was attacking the problem at about the same
time as Warington, gets most of the credit. Yet it is the discoverer,
the conceivor of new ideas, the initiator of new methods, who is
really deserving of most praise.

Since Frankland' s discovery of the nitrous ferment in England it
has been found that the process is not carried out by the same
organism in all parts of the world. Different kinds of bacteria,
some of them motile, act as "nitrous ferment" in different parts of

J Winogradsky, Annales Inst. Pasteur, 1890, 1891.

* Warington, Journ. Chemical Soc., 1878, 1879, 1884, 1891.

8

the world. But in all parts of the world it is the same bacterium
which is responsible for the production of nitrates.

In America the living bacteria of suitable soil are actually culti-
vated and distributed for trial in poor soils, by the U.S. Depart-
ment of Agriculture.

In the laboratory, where pure cultures can be obtained, these two
organisms can be demonstrated separately, but in nature they work
simultaneously. They are most active a few inches below the
surface, for, like most bacteria, they work in the dark and object to
the light of day. This nitrification of the soil by means of bacteria
can take place only under certain conditions, namely, the presence
of small amounts of easily oxidisable organic matter. In other
words, imperfectly rotted manure is detrimental to their activity.
Hence the importance of applying well-rotted manure to crops. They
will not tolerate acid condition, hence the need of a sufficiency of
carbonate of lime. In this manure the ammonia arising from
the action of putrefactive bacteria is changed into carbonate, which
is rapidly converted by ' ' Niirosomonas " to nitrites, and then by
" Nitrobacte r " to nitrates, the changes proceeding so rapidly that only
traces of ammonia or nitrite are ever found in normal arable soil.
Absence of air puts an end to the activity of the bacteria — heiioe
the importance of harrowing.

From these lacts it seems that if and when the vast deposits of
nitrate in Chili and Peru become exhausted, it would be possible to
make nitre artificially by the aid of bacteria. f But that is for the
future.

In addition to these nitrifying bacteria there are in the soil
numerous organisms that are able to nx atmospheric nitrogen, and
of these a bacterium, "Azotobacter," is most important. For the
action to be rapid the bacteria must be sufficiently provided with
carbonate of lime, potash, phosphates, organic matter, and moisture.
A suitable temperature must be maintained.

It has long been known that leguminous plants will nourish on soils
that are very poor in nitrogen, on sandy soils for instance, and it
was for many long years a mystery as to how they managed to do
this. It was known as long ago as 1866 that the root nodules that
occur on lucerne, beans, clover, vetches, and other leguminous plants
contain bacteria^ and it is now known that these have the power of
tixing free nitrogen; these plants are independent of nitrogenous
manures. These facts are perfectly familiar to everyone, and form
an important factor in the rotation of crops. These plants can be
used in increasing the supply of nitrogen in cultivated soils and re-
claiming barren sands and clays. Wherever leguminous plants grow
they enrich the soil in organic nitrogen through the co-operation of
nodular bacteria. When the host plant dies or is ploughed into the
'land the nitrogen compounds are speedily changed into plant food.
Few improvements in agriculture have produced more marked effects
than the extension of leguminous cropping. Yet how were these
facts discovered? By countless experiments lasting over many

tBurnet, Etienne. "Microbes and Toxins," 1912, p. 15.

years during which time a number of scientific men discovered the
facts whicli constitute our present knowledge.

It was the French chemist Berthelott who in 1885 suggested that
there might be in the soil certain organisms that were able to fix
atmospheric nitrogen. It was a German botanist, Hellriegel, who
m 1886 suggested that in the case of the leguminous plants this
property was possessed by the bacteria in the nodules. It was at
itothamsted that Lawes and Gilbert made the field trials and labora-
tory experiments that established the truth of these suggestions and
made them available to agriculturists.

Glancing over what I have said, it becomes clear that we owe a
big debt of gratitude to these extremely minute but extremely abun-
dant bacteria. We are so accustomed to think of them as harmful,
as the cause of disease, on which medical men are never tired of
insisting, that the general public may be pardoned if they do not
recognise, or even know, of the vast utility of these microbes.
Indeed, the disease-producers are comparatively few, and we are
justified in saying that "All bacteria are useful and beneficial to
humanity, though some have become injurious by the accident of
their location within our bodies under certain circumstances." Life
as a whole could not continue without their aid. They do not
create life, perhaps, but they supply it with the necessary main-
tenance. It is by their means that the remains of dead animals and
plants are cleared away and the organic substances stored up in them
are returned to the air and soil in the form of inorganic matter, and
rendered once more available for the food of plants.

As the prophet says, + " All flesh is grass" — the sheep feed upon the
grass, we feed upon the sheep ; hence our food supply is in the last
resort dependent upon bacteria of the soil.

PROTOZOA OF THE SOIL.

It is known that at times and under certain circumstances a soil
Icses its nutritious character and becomes "sick" in spite of the fact
that it has received the usual amount of proper manure.

This subject attracted the attention of Dr. Russell and Mr Hutchin-
son a few years ago (1909), t and they found that if such a soil be
partially sterilised by being heated to a temperature of about GOdeg.
Centigrade, or if it be treated with some volatile antiseptic such as
toluene, the number of bacteria normally present undergoes
remarkable changes. At first this number is greatly reduced, which
means the soil has lost in nutritive character. Then there is a very
marked increase. This rise in number sets in soon after the removal
of the antiseptic or after sterilisation has ceased, and the soil condi-
tions are now more favourable to the development of bacteria, and

tBerthelot, "Fixation directe de 1'azote atmospherique libre par certain
terrains argileux." Comptes Rendues. 1885.

Jlsaiah, chap, xl., verse 6. The prophet used the expression, of course, with an
entirely different connotation.

tRussell and Hutchinson, "Journ. Agric. Science," vol. iii., 1909.
Proc. Roy. Soc., vol. 84, B., 1911, p. 165.

10

their number continues to rise till it exceeds that present in the
original soil. Simultaneously there is a marked increase in the
ammonia. It is evident that the soil has been improved by the
treatment, and this improvement is found to be permanent. They
argued, tnerefore, that there must be in the soil some factor that
limits the activity of the bacteria, and since this limiting factor is
abolished by the treatment it cannot be the lack of anything, but
must be the presence of something which is affected by the treat-
ment. They came to the conclusion that some living tilings exist-
ing in the soil were detrimental to the bacteria. They proceeded to
search for these living things in cultures of untreated soil, and
they discovered the presence of minute animals known as
Protozoa. The investigation is a very difficult one, and these
difficulties are only now being partially overcome.

Stimulated by these preliminary observations, several biologists
proceeded to examine the fauna of soils, and a series of researches
published in 1911, and still going on, has already resulted in the
discovery of quite a large variety of much larger organisms, though,
of course, they are still of microscopic size.t These are unicellular
animals or Protozoa, known to us as Amoebas, Flagellates, and
Ciliates, such as exist in great numbers in pond water and in sewage.
\ They are now known to occur in considerable numbers in the soil,
being especially numerous in "sick soil," where there may be as
• many as thousands to a gramme, which is, indeed, but a low number
. compared with the bacteria, which occur in millions per gramme of
soil. It is these Protozoa that feed upoit the bacteria, and hence
the cessation of the important nitrifying process. When the soil
is treated by partial sterilisation or by antiseptics, the Protozoa are
killed, while the more hardy bacteria may escape, but after the re-
moval of the toluene, or after sterilisation has ceased, the bacteria
renew their activity and multiply rapidly.

This then is an important additional piece of knowledge allowing
soils to be effectively treated when they become sick. Until this
discovery was made any attempt to effect a remedy could only be a
matter of working in the dark.

It is found, indeed, that burnt lime, quick lime, spread on the
soil has the same effect as partial sterilisation. It kills the Proto-
zoa, whereas ordinary carbonate of lime does not.

tGoodey, "A Contribution to our Knowledge of the Protozoa of the Soil,"
Proc. Roy, Soc., vol. 84, B., 1911, p. 165.

Martin, "A Note on the Protozoa of Sick Soils, with some account of the
Life-Cycle of a Flagellate Monad," ibid., vol. 85, B., 1912, p. 393.

Thornton and Smith, "On the nutritive conditions determining the growth of
certain Freshwater and Soil Protista," ibid., vol. 88, B., 1914, p. 151.

Russell, "Soil Protozoa and Soil Bacteria," ibid., vol. 89, B., 1915, p. 76.

Goodey, "Further Observations on Protozoa in Relation to Soil Bacteria "
ibid., vol. 8*9, B., 1916, p. 297.

Martin and Lewis,' "Some Notes on Soil Protozoa," Phil. Trans R Soc vol
205, B., 1914, p. 77.

JHutchiason, "Journ. Agric. Science."

11

PLANT DISEASES.

In approaching the second part of my address I cannot improve cm
(.he following succinct statement on the matter of disease, by Prof.
Keeble :— t

"About fifty years ago the belief that disease is the work of male-
ficent evil spirits still lingered in the minds of simple folk, and though
the better educated had given up that idea they were very little
wiser.

"At about the time (1877) that Pasteur was studying the nature
of diseases in animals, a botanist, de Bary by name, demonstrated
that many diseases in plants are due to the entrance of a parasite
into the body of the plant. In some cases it is a fungus, and specific
diseases are due to specific fungi : in other cases bacteria. Gradually
contemporary and succeeding workers arrived at a precise apprecia-
tion of these infectious diseases. As a result of their prolonged
labours it is now recognised that three conditions are necessary to
make that quarrel that we call disease: —

"(1) The existence of an infecting organism, whether it be a
bacterium or a fungus.

"(2) The condition of the plant which exposes it to attack or
screens it from attack. .

"(3) Conditions in air or soil which favour either the parasite or
the plant and so facilitate or discourage the attack.

"The professional botanist, i.e., the plant pathologist, is apt to fix
his attention too exclusively on the first of these conditions. He is
naturally more interested in the structure and life history of the
fungus. The professional agriculturist seeks to preserve his plants
from disease by improving his methods of cultivation. There is
much room in the world for a race of botanists who not only discover
how to cure plants but know how to cultivate them, and from wide
experiments to endeavour to find varieties which are immune to
specific disease."

In a work on "Diseases of Economic Plants," published in America
in 1916, I find that no fewer than two dozen infectious diseases are
there known to attack the apple trees alone — the fruit, the leaves, the
bark, the root. Some are due to bacteiia; others to fungi; others
appear to be functional. Some of these are limited to the United
States, some to only parts of the States ; others are more widespread.
Many of them can be distinguished from others only by a botanist
who is familiar with the disease-producing fungi or bacteria.
Further, several of these diseases are outwardly similar to one
another, and yet may be caused by quite different parasites. The
use of such names as "black spot," "scab," and so on, does not
necessarily mean that what is so named in America is identical with
that so named in Australasia, and consequently a particular treat-
ment which may be found useful in one part of the world is not
necessarily beneficial in some other locality.

tKeeble, "The Science of Botany ar.d the Art of Intensive Cultivation" in.
"Science and the Nation," edited by Seward. 1917.

12

Until the attacking organism, be it fungus, bacterium, or insect,
is tracked down, and its life history studied by a competent biologist,
ir, is little more than a waste of time in many cases to guess at the
cause of the disease.

Further still, some of the diseases, such as the apple rust, are due
to a fungus which presents two distinct phases in its life history, in
one of which it attacks the apple, in the other usually some other
plant which need not be the same in all parts of the world, and
which has to be sought for in each locality.

Again, there are various insects like the codlin moth and others
which, as you are aware, do much damage to our apple trees when
once they gain an entrance into the orchards. In Collinge's "In-
jurious Insects" I find he enumerates 29 insects which attack
apples in England.

I was appalled at the list as enumerated in these two works, and
I came to the conclusion that I would not touch so big a subject
in any particularity.

"You must remember that," as Prof. Gregory t puts it, "every
fly that troubles the agriculturist, every fungus that infests his
plants, has to be studied laboriously by biologists specially trained
in these particular matters before any accurate knowledge of its life
history and its habits can be elucidated, and only then can means of
suppression or amelioration be suggested. Whatever is known of
the exact relation between cause and effect in all branches of agricul-
ture, and whenever fact can be placed against opinion as regards the
diseases of plants, the credit is found to belong to the scientific
investigator, and not to the actual cultivator of the soil."

But I will refer to two diseases : "Bitter pit" and "Crown gall."

In the case of "bitter pit" I would remind you that the Australian
Commonwealth Government appointed a well-skilled botanist to
investigate the cause of the disease and to suggest a cure and preven-
tion. Professor McAlpine, with other botanists, has been at work
on this problem for some three or four years, and only now is he
prepared to state how the disease arises and to propose remedies.
From the reports that have been published from time to time+ by
Professor McAlpine, it is clear that this disease presents many com-
plications. In the first place he has shown that it is not due to
bacterium, nor to fungus, nor to the attacks of any insect or other
animal, but that it is what is called a functional disease, and is due
to some defect in the physiology of the plant. Many theories have
been propounded to account for it, some of them founded on observa-
tion ; others merely speculative. But from the later reports it
appears to be due to the death of some of the pulp cells immediately
below the skin, which is not ruptured, at any rate in early stages of
the disease. In order to ascertain the probable cause McAlpine
had first to make a more careful study of the anatomy of the apple
fruit than had been hitherto done. He found that it is penetrated

tGregory, R. A., "Discovery: or, The Spirit and Service of Science" (Mac-
millan.

JD. McAlpine. The Cause and Control of Bitter Pit. Government Printer, Melbonrne.

13

by an immense number of extremely fine vessels which distribute the
sap throughout the growing fruit, and that owing to the imperfection
of some of these vessels near the skin there is not that proper co-
ordination between the amount of water received by the apple from
the tree and that removed by transpiration, so that extra pressure
is exerted by the contents of the cells which then burst. He admits
that he is not quite clear as to whether this is the effect or the cause
of the disease.

The attacks of "bitter pit," he says, are most virulent where the
sap flow and the transpiration are subject to violent alterations.
Hence the disease is traceable in some degree to climate and in some
degree to the variety of the apple.

I need not enter here into the various practical applications of his
discoveries, but he notes that varieties vary considerably in their
susceptibility to "bitter pit" ; while some varieties are liable in one
district, they are fairly free in others. The commercial varieties
best suited to the district should be considered in planting out the
orchard and a suitable site chosen.

'Stated generally, excess must be avoided and moderation practised
in the various orchard treatments, such as pruning, manuring, and
irrigation. Tho object is to maintain as far as possible steady and
uniform conditions of growth.

I will take the other disease, the "crown gall" or "hairy root."
Some time last year a consignment of young apple trees was
received from Australia, but they were condemned in New Zealand
by the Inspector of the Agricultural Department as being attacked
by an infectious disease. The consignors and the Australian Agri-
cultural Department were naturally annoyed at this. They
contended that the disease "crown gall" is not infectious. And so
representatives were sent over to try and convince our people that
there would be no risk in allowing them to come into the Dominion.
The Agricultural Department had recourse to the Professor of
Bacteriology at the University of Otago, and cultures were made
in his department and under his supervision. Subsequently, Mr
Waters, who had studied biology under Professor Kirk at Victoria
University College, and bacteriology under the guidance of Professor
(Jhornptaloup. took up the subject. He had been in communication
with American plant pathologists and received cultures of the or-
ganism that is responsible for the "crown gall" for comparison
with those in the imported plants. He established the fact that here
too, as in America, the disease is infectious, that it will attack not
only apple trees but other plants — that if the bacteria get into a
wound the disease makes its appearance in a few weeks.

Incidentally, I may mention that while at Dunedin Mr. Waters
has turned his attention to another important matter. He has been
able to make cultures of the bacterium which constitutes the essen-
tial feature in the "starter" used in cheese-making. Hitherto, as
you may be aware, these starters have been imported from Europe
in the form of powders, and they have not always been quite satis-
factory or reliable owing to the length of time they have been in
stock and from other causes. But Mr, Waters has been providing

14

the local dairy farmers with freshly prepared starters with very
satisfactory results. In time, no doubt, the Government will be
able to manufacture these starters and supply them throughout the
Dominion, and thus provide our dairymen with more reliable cultures
than those that they make for themselves from the imported powders.

THE NEED FOR RESEARCH.

I mention these facts in order to impress upon orchardists that
there is no short cut to the making' of important discoveries. The
day of empiricism is or ought to be past, and no advance can be
made in the diagnosis of disease or the finding of a remedy without
more or less prolonged research.

The work of pure science is intimately related to industries
of all kinds, and not least to agriculture. It is true that the man
,^1-ag scientific work in the laboratory may not have sufficient
acquaintance with the industry to see exactly the best way in whicn
to employ his new-found knowledge, but the industrialist ought to be
so educated as to be able to apply it for himself.

In a recent number of "Nature" I read an article on the "Organi-
sation of Research in Agriculture,"^ where a contrast is drawn
between the encouragement given by Germany to research and that
given by Britain, and I may add, by British colonies in general. It
is not that German science is any better than that of British scientific
men, or that more important discoveries have originated there,
for, as we have seen, many valuable lines of investigation have been
initiated in England, but the Germans have appreciated the value of
scientific research to industries in a way that British people never
have, till the present war has forced the Government to recognise
the importance of employing scientific men to solve many of the
difficulties met with by industrialists in their present needs. "The
German people as a whole believe in the economic value of know-
ledge, respect the scientific method, are eager to give practical effect
to the results attained by that method, and as a result are ready to
submit their industries to scientific direction. It will avail us little
to endow scientific research unless scientific knowledge is treated
with greater deference than it has been in the past. The fond belief
that scientific results can be ordered and paid for Tike goods and
that the knowledge which gives these results birth has no continu-
ing value must be abandoned if we set out to compete with the
German in his own field."

As evidence of the hold which scientific work has gained on the
German agriculturist, we have the 'remarkable fact that some years
airo the German farmers and landowners raised a sum of one and
a-half million pounds sterling which they presented to the Kaiser
for the purpose of founding- industrial and agricultural laboratories.
The gross revenue of the agricultural research stations in Germany
approaches £400,000 ; in England only £40,000 ; whereas in America
it reaches one million pounds.

*"The Organisation of Research in Agriculture" — in "Nature." Fefc 28
1918, p. 507,

15

"Discoveries are not made by a stroke of a magician's wand.
What the State or any Research Institute should provide for the
scientific worker is the means of research. It should not impose
methods or predetermined ideas, otherwise all initiative will be
stifled."

Now I think that we in New Zealand may learn something from
thie article which I have here summarised. Mr. Cawthron has
provided the means for research ; and it is not sufficient to know what
has been done as the result of previous researches. It is necessary,
if orchardry is to improve to have really competent scientific men
who are capable of initiating research, of adding to the already
existing stock of knowledge, and these men must be left untram-
melled by laymen, and allowed to pursue their investigations on
their own lines, even if no immediate beneficial results are ob-
tained. Merely to treat the fruit trees as they have been treated
hitherto by some one else in some other part of thfe world is not
going to lead to any real improvement in cultivation.

I am glad to hear that recently a body of New Zealand industrial-
ists have come to recognise that it would pay them to employ science
in certain difficulties that had met them in their work. The Flax-
millers' Association and the owners of the Makerua flax swamp a few
months ago requested Dr Leonard Cockayne, F.R.S., to investigate
a certain diseased condition that had appeared in the flax plants.
The value of this industry is somewhere about a million pounds
annually, and it employs a large number of people. It seemed likely
that this important industry would in a few years be wiped out unless
something could be done to stop the disease. I do not know that
he has finished the work, but I understand that he has satisfied him-
self as to the cause of the disease, and no doubt his observations
and experiments will have beneficial results. It is, I believe, the
first time that any extensive industry in New Zealand has called in
the aid of the scientific man to solve its difficulties. Yet surely an
industrv of this monetary value was wise to expend a few pounds
in getting scientific advice. This is the kind of thing that the or-
chardists mio-ht do, ^ven if it is at present impossible to build and
onmD the Cawthron Institute. Let them band themselves together
PTH! employ men trained in scientific method in order to overcome
the troubles that some of them suffer from.

To use Bordeaux mixture or some other fungicide for every sort
of fungoid pest is good enough for small farmers who can carry out
the excellent instructions given by the experts of the Agricultural
Department, but the aim of the Research Institute should be some-
thing more than this — to find out the life history of each particular
pest which in this particular district attacks this or that particular
variety of apple or other fruit tree, whether it be the leaves, the bark
or the fruit — to track it down and find out in this way what means
can be devised to put a stop to its development before it attacks any
more trees. "Prevention is better than cure" is an old adage with
much truth in it.

There is here any amount of work and abundant opportunity for
a well-trained, and by that I mean a scientifically-trained, plant

16

pathologist to work out the whole life history of each fungus. Much
is being done in America and France ; very little has been done in
New Zealand. The conditions here are different from those in
America or Britain, the diseases are different; the remedy obtained
elsewhere can only be a guide to us here; but it is part of the work
of the scientifically trained man to know what has been done elsewhere
before he begins to work, and then to improve the method.

As I have attempted to show you, the knowledge that we have
to-day on which depends a proper system of manuring, and the same
could be said of cultivation in general, is the result of the experi-
ments of many farmers, agriculturists and scientific men. It
has occupied the close attention of men trained in the scientific
method, not for a month or two, but for years. That is why the
commission on which I had the honour to sit offered the advice to
the Trustees of the Cawthron Institute to proceed slowly, and see to
it that the Director should be a first-class man, trained to deal with
the various chemical aspects of agriculture, with experience gained
at one or other of the large Institutes in Britain or America ; then
to appoint an equally well-trained plant pathologist to investigate
the diseases, to find out their cause and to initiate experiments as to
their prevention.

WORK FOE THE INSTITUTE.

It will be seen that much of our present day knowledge on
manuring is the result of long-continued experiments in soil biology,
carried out in the first place by Englishmen. Much remains to be
done, and there is a fruitful line of work for the Cawthron Institute.
There is plenty of room for research conducted on scientific lines on
the matters referred to in Mr. Allport's report to the trustees, which
is included in the report of the commission.

There is need for systematic experiments on the efficiency of
different kinds of sprays qn different kinds of trees, both as to
strength to be used and the proper time to use them, as well as the
effect of the sprays on the health of the trees. No systematic record
appears to have been published on such matters as these. Then we
ought to have experiments to decide what are the most suitable
stocks upon which to propagate the apple trees, and to endeavour to
find such a stock and variety as would be immune from different
types of disease. The most productive methods of pruning, too,
and the most suitable and economic methods of manuring, should be
investigated.

Amongst other matters that ought to receive attention are : —

(1.) A thorough soil survey, the investigation of the
chemistry, physics and biology of the soil, and especially of the
humus and its effect on plant growth, of which little is as yet known.

(2.) An extended programme of investigation of the diseases that
attack our plants and especially those that are injurious to the fruit
tree.

These are a few of the lines of research, which in the near
future should occupy the attention of the Cawthron Institute.

R, W, STILES & CO., PRINTERS, WAIMEA STREET, NELSON,

CAWTHBON LECTURE

1919.

The Distribution of the Vegetation and
Flora of New Zealand.

BY

L. COCKAYNE, PH.D., F.L.S., F.R.S.

CONTENTS.

PAGE

1 . General Remarks ... ... ... ... 3

2. The Natural Floristic and Ecological Divisions ... 6

(a) The Coastal, Lowland and High-mountain Floras 6

(1) The Coastal Flora ... ... ... 6

(2) The Lowland Flora ... ... ... 7

(3) The High-mountain Flora ... ... 8

(b) The Botanical Subdivisions of the New Zealand
Region ... ... ... ... 9

3. Some outstanding Features of Plant-distribution in New

Zealand ... ... ... ... 11

(a) Cook Strait not a barrier to plant-distribution ... 11

(b ) The relation of Latitude to plant-distribution ... 12

(1) General ... ... ... ... 12

(2) Latitude 36 °S. as a phytogeographical barrier 13

(3) Latitude 38° S. as a phytogeographical barrier 14

(4) Latitude 42°S. as a phytogeographical barrier 15

(c) The effect of the Southern Alps and the Coastal

Mountains of North-western Nelson on plant-
distribution ... ... ... ... 16

(d) The effect of the frequent south-west wind on
plant-distribution in the South Island and Stewart
Island ... ... ... ... 18

( e) The effect of altitude on plant- distribution ... 20

(f) The effect of the edaphic factor on plant-distri-
bution ... ... ... ... 21

4. Continuous and discontinuous distribution ... ... 25

Addenda . 27

LECTURE III.

THE DISTRIBUTION OF THE VEGETATION AND
FLORA OF NEW ZEALAND.

By L. COCKAYNE, PH.D., F.L.S., F.N.Z.lNST., F.R.S.

1.— GENERAL REMARKS.

The vegetation of New Zealand composed, as it is, of
numerous plant-associations varying in their characteristics
from subtropical to subantarctic and from hygrophytic to in-
tensely xerophytic, together with the species of diverse origin
(Palaeozelandic1, Malayan — including Polynesian — Australian
and Fuegian2), offers excellent material for studies in plant-
distribution which should be of general phytogeographical
interest. Such studies, too, are simplified by the comparatively
small flora (about 1830 species of vascular plants) to be dealt
with, the somewhat less extreme complexity of the ecological
factors than that which botanical regions with an equally
diverse vegetation afford, and the clear-cut effect on distribu-
tion over a wide area of a sudden change in the rainfall.

It need hardly be pointed out, that in the brief time allowed
by a lecture, only a quite incomplete sketch of the subject under
consideration can be presented, though it should be possible
to portray some of the more striking features of New Zealand
plant-distribution.

The New Zealand Botanical Region includes not only New
Zealand proper (North Island, South Island, Stewart Island,
and the islets adjacent to these) but also the Kermadec Islands,
the Chatham Islands and the New Zealand Subantarctic Islands,
thus extending from lat. 29deg. 15min. S. to lat. 54deg. 30min.
S. (Macquarie Island). In this lecture, however, excepting
when illustrating certain points, distribution in New Zealand
proper is alone dealt with.

Regarding the available material from which this lecture
is prepared, it might be objected that such is inadequate. New
Zealand, it may be argued, is far from being fully explored
botanically, so that the actual distribution of many species can-
not be known ; while, as so much of the primitive vegetation is
modified, or destroyed, it must be impossible to picture accur-
ately its primeval physiognomy and composition, or to trace its
distribution. Such objections are valid only to a minor degree.
It is true that much remains to be accomplished before a full
list of specific forms and complete details of their distribution

!• For explanation of this term see L,. Cockayne, " New Zealand Plants and
their Story," 2nd Edition, 1919, p. 205.

2- This is the Subantarctic South American element, but here called " Fuegian"
in qrder to avoid confusion with the New Zealand Subantarctic flora.

are available; but, during the past fifteen years, that is, since
the publication of Cheeseman's "Manual of the New Zealand
Flora," there has been unparalleled botanical activity in the
Dominion. Many new species have been discovered and much
has been added to the knowledge already existing regarding
the distribution of the older species; nevertheless, this recent
knowledge has been rather in the direction of confirming the
older ideas than of disproving them. It may, indeed, be asserted
that, for all practical purposes, the present knowledge of the
distribution of New Zealand vascular plants is sufficiently accur-
ate to permit the establishing of reliable conclusions on certain
fundamental points.

With regard to its vegetation. New Zealand has been sin-
gularly fortunate in having had from the earliest days of
settlement, when virtually all the plant-covering was primitive,
a number of ardent naturalists, who, if not supplying a picture
of the vegetation from the modern ecological standpoint, have
given such indications of its nature as to permit anyone versed
in the subject to read between the lines. Still, this would have
been inadequate were it not that numerous areas, large and
small, of virgin vegetation stand unmolested in all the plant-
geographical districts; or, where modified, many are not yet
so seriously damaged as to have effaced the primeval stamp.
In the South Island, more especially, there are extremely exten-
sive tracts still truly virgin, but at present unsuitable for5
settlement ; while, in all parts of the Botanical Region, numerous
reserves, some of great extent, have been set aside as sanctuaries
for the indigenous plants and animals. Second in importance
to none of such sanctuaries is the late Mr. Cawthron's splendid
gift to Nelson and to the people of New Zealand — the "Cawthron
Park" (see Fig. 1.) Other reserves may, in course of time, be
alienated, or interfered with, but the Cawthron Park can never
be turned from the object for which it was set aside by its far-
sighted founder. Never should plant or animal foreign to its
precincts be permitted to desecrate its sanctity. Through the
long years it should remain, as its founder intended, a living
monument builded by Nature and by Her alone to be maintained
it all its pristine beauty !

The study of plant-distribution is two-sided. First of all
comes the comparatively easy task of noting and recording the
facts of distribution; while, in the second place, is the vastly
more difficult matter of referring such facts to their causes.
Here comes in the estimation, of the effect of those two complexes
of ecological factors, climate and soil. Then, too, there are the
biotic factors, i.e., the relation of the living organisms — plant
and animal — to one another, and their effect upon the habitat
of the plant-association as a whole, or upon the various growing-
places of its members. Then there are the historical factors
to consider dealing with the histories of the species and the
geological history of the area they occupy. No particular sec-
tion of this lecture is devoted to these questions of ecological
and historical factors, highly important though they be, still

Photo., W. C. Davies.
: View of piece of southern-beech (Nothofagus) forest in Cawthron Park.

they are not entirely neglected, but receive some consideration
when certain cases of distribution are discussed.

Generally in researches dealing with phytogeographical dis-
tribution, the vegetation receives no consideration, the
distribution of the species being alone the theme. Such treat-
ment of the subject is not on natural lines. The species are
the ultimate units of the vegetation, and its distribution includes
that of the species. Once a species has become a member of one
or more plant-associations, its movements are apparently
governed by those of the associations to which it belongs. The
dynamics of plant-distribution, except before an association is
stabilized, is not a moving of individual species, but of plant-
associations. Once an association has become stable, it can
receive only with the most extreme difficulty additional species
from elsewhere. The gradual evolution of the association has
led to rigorous selection and the final product is perhaps the
most epharmonic that the species available would permit. For
one hundred years, or thereabouts, a gradually increasing band
of plant-immigrants has attempted to gain a footing in the
virgin associations of New Zealand, and yet, despite the many
millions of seeds cast forth yearly, not one introduced plant has
been able to gain a place in any purely virgin plant-association,
if certain water and rock associations be excepted. Foreign
plants there are in profusion growing wild throughout the
length and breadth of the islands along with the indigenous
species, but this is only in those plant-associations which have
been directly or indirectly modified or brought into existence by
the action of man himself, his grazing animals, or his fires3.

As this lecture treats of plant-distribution in New Zealand
it might well be expected that I should say something regarding
Willis's "Age and Area Theory," since that distinguished author
bases it to no small extent on the distribution of the vascular
plants of New Zealand*. However, at the present time, I have
not the leisure to deal with that important generalization, since,
apart from special crticisms, I should like to examine it by
means of a quite different set of figures from those used by
Willis which would take into consideration not merely latitudinal
distribution in one plane, but would deal also with vertical dis-
tribution and distribution according to the plant-formations, or
even the clearly marked plant-associations. Nor do I think that
the distribution of the high-mountain plants — a flora, as may
be seen further on, amply distinct from those of the lowlands
and sea-coast — can be treated along with the two last-mentioned
floras. The flora of the high-mountains is essentially a South
Island and Stewart Island matter, for the paucity of the North

3- For a detailed account of the behaviour of the introduced plants in New
Zealand see Cockayne, L., "New Zealand Plants and their Story," Ed. 2, 1919,
pp. 144-158.

4. Willis, J. C., "The Distribution of Species in New Zealand," Ann. Bot.,
vol. xxx, 1916, pp. 437-57, together with other papers on New Zealand distribution
which have appeared in the same journal at later dates.

Island high-mountain flora is probably due — as pointed out later
— rather to there being so little space above the forest line for
its development than to any other cause. Also it cannot extend
further north than the Thames Mountains, these being the final
heights suitable for occupation by other than forest plants, while
on them it is the wind factor alone which has rendered the small
high-mountain element possible. Other statements and facts
appear in the body of this lecture which have an obvious bear-
ing on Willis's work, but I am purposely not calling attention
to their import. To Dr. J. C. Willis, F.R.S., as he has pointed
out5, I wrote some time ago at considerable length regarding his
theory, and he has done me the honour in referring to this letter
to state that my suggestions and criticisms will receive consider-
ation in his further papers on New Zealand

Before concluding these general remarks, I must express
my thanks to Mr. W. C. Davies, Curator, Cawthron Institute, for
valuable assistance in preparing the photographs for publication
and to Mr. F. G. Gibbs, M.A., whose untiring labours have
thrown a flood of light upon the distribution of the Nelson
flora.

2.— THE NATURAL FLORISTIC AND ECOLOGICAL

DIVISIONS.

(a) The Coastal, Lowland and High-Mountain Floras.

From the standpoint of distribution it is not satisfactory to
deal with either the flora or vegetation of New Zealand as a
whole, since both may naturally be divided into three groups,
virtually independent of one another — the coastal, the lowland
and the high-mountain — each of which possesses a large per-
centage of species, associations, and to some extent growth-
forms, wanting in the other two groups. There are also a
considerable number of generic and some family distinctions.

(1) THE COASTAL FLORA.

The coastal flora consists of about 144 species which are
confined to the coast-line, or its immediate neighbourhood ; also
some 46 species which occur inland to a limited extent are
virtually coastal. Eight families and 35 genera are confined, or
almost so, to the coast-line. Possibly about 100 species occur
both inland and on the coast, some of which ascend far into the
high mountains, e.g., Aciphylla squarrosa6 , Celmisia Lindsayi
(see Figs. 2 and 3), Claytonia australasica, Dracophyllum
longifolium, Gunnera albocarpa, Netera Balfouriana, Metro-
sideros lucida, Olearia Colensoi, 0. Fosteri\ O. insignis,
Phormium Colensoi, Raoulia australis var., R. apice-nigra,
Scirpus aucklandicus, Senecio lagopus var., and S. Monroi.

5- "The Flora of Stewart Island (New Zealand): A Study iu Taxonomic
Distribution," Ann. Bot., vol. xxxiii, 1919, p. 42.

6- None of the lists in this article aim at completeness.

?• This species ascends to about 4000ft. altitude in the Inland Kaikoura
Mountains.

The principal ecological factor determining the presence of
true coastal species is an excess of salt in the soil above that
which ordinary inland plants can tolerate. Thus the plants
of salt-swamp, salt-meadow, seashore, and rocks exposed to sea
spray are mostly actual coastal species, e.g., Arthropodium
cirratum, Atriplex Billardieri, Atropis stricta, Avicennia
officinalis, Carex litorosa, Crassula moschata, Mesembryanthe-
mum australe, Mimulus repens, Rumex neglectus, Salicornia
australis, Sonchus littoralis, Suaeda maritima. But the follow-
ing characteristic coastal, salt-tolerating species occur in one or
more localities far inland : Eryngium vesiculosum, Juncus
maritimus var. australiensis, Leptocarpus simplex, Scirpus
americanus, Selliera radicans, Triglochin striatum *var. fili-
folium, Apium filiforme and Samolus repens var. procumbens.

The comparatively mild climate of the coast as compared
with that further inland is responsible in part, at any rate, for
the presence of species which cannot tolerate much frost. To
this category the following probably belong: Avicennia
officinalis, Coprosma Kirkii, C. retusa (C. Baueri of the Manual),
Corynocarpus laevigata, Dodonaea viscosa (in the southern part
of its range), Dysoxylum spectabile (in the southern part of its
range), Entelea arborescens, Hymenanthera novae-zelandiae,
Macropiper excelsum (in the southern part of its range),
Myoporum laetum (in the southern part of its range), Olea
apetala, Paratrophis opaca, Pisonia Brunoniana, and Sideroxylon
novo-zelandicum.

Moving dunes present uncommon conditions demanding
special growth-forms for their plant inhabitants and sucfr swell
the list of purely coastal plants. There are the major sand-
binders: — Scirpus frondosus, Spinifex hirsutus and Euphorbia
glauca; the minor sand-binders, Calystegia Soldanella and Carex
pumila; and the sand-collectors, Cassinia retorta, Coprosma
acerosa, Pimelea arenaria and P. Lyallii8, this also a sand-
binder to some extent.

There are many different coastal plant-associations besides
those already mentioned, some of which (forest and shrub
associations) are dealt with when treating! of distribution in
regard to latitude.

(2) THE LOWLAND FLORA.

The lowland flora (including in this term the flora of the
lower parts of the mountains up to 2000ft. altitude as an aver-
age) contains about 1009 species, of which some 517 are purely
lowland, 350 (many extremely common) also belong to the high
mountains, 100 are virtually high-mountain plants but they
occur in the lowlands under special circumstances, and 42 are

8- Here the view is taken that the name Pimelea Lyallii be restricted to the
sand-hill plant of the South Otago'and Stewart Districts and that the high-
mountain plants formerly referred to this species fall into one or more unnamed
species, excluding the bushy shrub of Central Otago which I am naming elsewhere
Pimelea aridula.

8

usually coastal. No less than 15 families and 93 genera are
confined to this lowland-lower mountain belt.

The following are the families confined to the area under
consideration : — Amaryllidaceae, Elatinaceae, Gesneriaceae,
Icacinaceae, Oleaceae, Lauraceae, Lemnaceae, Meliaceae, Moni-
miaceae, Palmae, Pandanaceo.e, Passifloraceae, Rutaceae,
Salviniaceae, and Sparganiaceae. Nine of these families have
only one species each, and none have more than four species.
Much more important than any of the above in the lowland
flora are the following: — Filices (85 species), Cyperaceae (46
species), Orchidaceae (45 species), Compositae (41 species),
Rubiaceae (19 species), Gramineae and Scrophulariaceae (16
species), and Myrtaceae (13 species).

Coming next to the plant-formations, the most important
are forest and grassland. Their distribution receives some
attention under another head. Shrubland, swamp and bog are
also important ecological groups. At the present time there is
abundant Pteridium (bracken-fern) heath, but how much of it
is primitive no one can say, for it is readily induced by burning
forest and certain classes of scrub.

(3) THE HIGH-MOUNTAIN FLORA.

The high-mountain flora differs to an astonishing degree
from that of the lowlands. It contains in all some 950 species.
If about 100 species which occur in the lowlands only under
special conditions be added to the purely high-mountain plants,
this element of the New Zealand flora will number about 600
species.. The following 15 genera (7 endemic) are essentially
high-mountain: — Corallospartium (end.) Exocarpus, Forstera,
Haastia (end.), Hectorella (end.) Logania9 Leucogenes (end.),
Marsippospermum, Mitrasacme, Notothlaspi (end.) Pachycladon
(end.) Pernettya, Phyllachne, Swainsona and Traversia (end.).
In addition to the above, 32 genera, most characteristic of the
high mountains, possess far more high-mountain than lowland
species. The most important of such genera from the physiog-
nomic standpoint are the following: — Acaena, Aciphylla,
Anisotome, Celmisia, Danthonia, Dracophyllum, Epilobium,
Gentiana, Helichrysum, Olearia, Ourisia, Raoulia, Ranunculus
and Veronica.

The headquarters of the high-mountain flora is in the South
Island, to which more than 70 per cent, of the species are con-
fined. This is probably due in part to the fact that the
mountain-area of the South Island is far more extensive than
that of the North Island, owing partly to the far fewer and
lower mountains of the latter and partly to the forest ascending
higher. Thus Mount Egmont with its small area for plants
above the forest-line has at most 100 species as compared with
the 150 species of the more extensive high-mountain area of the

9- Through a slip in my book, " New Zealand Plants and their Story," the
family Loganiaceae is stated to be purely high-mountain, but it includes the
strictly lowland genus Geuiostoma.

"

Photo., P. G. Gibbs.

'• FlG. 4 : Wide breadth of Celmisia Traversii growing in the lower sub-alpine belt of

Mount Arthur.

THRCC KINISSIt.f 1

C. Maria v. Dieman

Doubtless Bay

Bay of Islands

AUCKLAND
Manukau Hr

Three Kings ..... ^

North Auckland. ..,,

South Auckland

(a) Wiikato Subdistrict

(b) Thames Subdistrict
Volcanic Platean
East Cape
Egmont-Wanganui
Ruahine-Cook

(a) Wellington Subdistrict

(b) Marlborough Sounds Subdistrict
North-eastern South Island ....
North-western South Island ...
Eastern South Island
Western South Island

North Otago ....
South OtegO .... _
Fiord „. _

Stewart

Waikato R

NORTH

ISLAND i

Mokau IF

New Plymou
Mt. Egmbntz

HRISTCHURCH
nks.Penjn.

Map of

NEW ZEALANP

showing

Proposed Botanical Districts

Fig. 5 : Map of the Botanical Districts of the main islands of New Zealand.

From Trans. JV.Z. Inst.

Volcanic Plateau, or the 140 species of the Tararua Mountains.
But these last figures are not so strikingly different when the
isolation of Mt. Egmont and the difficulties in its original plant-
colonization be considered. There may be an additional reason
for the poverty of the North Island high-mountain flora. This
may be that a large percentage of the South Island high-moun-
tain sptecies is quite young — a conclusion warranted by their
affinities and also by their extreme polymorphy.

The vegetation of the high mountains differs greatly
according to their rainfall — a point stressed later. The forests
are largely made up of species of Nothofagus, but there are also
associations where Libocedrus Bidwillii and Podocarpus Hallii
dominate. In herb-field and fell-field the genus Celmisia is
represented by many species and growth-forms (see Fig. 4).
There are considerable areas of tussock-grassland, which on
the schist mountains may ascend to the highest summits, where-
as the readily-weathered greywacke mountains present great
diversity in their rock, debris and fell-field associations. Under
certain circumstances subalpine-scrub made up of shrubby
Compositae, Epacridaceae, Rubiaceae, and species of Veronica
is a remarkable feature, and it may become actual forest. At
high altitudes the cushion-form is often greatly in evidence;
it is also encouraged by dry stations.. The property of dead
leaves and other vegetative parts remaining attached to the
living plant in a wet, semi-peaty condition is a fairly frequent
characteristic of the high-mountain plants. So, too, strong
xerophily is common.

(b) The Botanical Subdivisions of the New Zealand Region.

The Botanical Districts as proposed by me in 1917 are
shown on the map (Fig. 5). These districts, it must be clearly
understood, are provisional only, and, to quote from my article
where they first appeared, "will be subject to considerable
modification for years to come." x °

There is no need here to define the boundaries of these
districts, nor to cite their names since both are shown on the
map. Nor am I giving the characters of each district, including
the lists of locally-endemic species. These matters are briefly
dealt with in the second edition of "New Zealand Plants and
Their Story," p. 180 — p. 194, and to this the reader is referred.
Here only certain critical remarks are made regarding the
boundaries of certain of the districts. First of all, however, the
principles upon which the delimiting of the districts was based,
may be quoted from the original article (loc. cit.). "In the
delimiting of a 'district' an attempt has been made to mark
off natural areas which are distinguished principally by the
following circumstances — some flor:..stic (these the most im-
portant, since the districts are essentially floristic), some
ecological: (1) The presence of a more or less extensive locally

tions of

- Cockayne, L., " Notes on New Zealand Floristic Botany, including Descrip-
of New Species, etc." (No. 2). Trans. N.Z. Inst., vol. xlix, 1917, p. 62.

10

endemic element; (2) the absence of species more or less char-
acteristic of adjacent botanical districts; (3) the presence of
species of restricted distribution elsewhere; (4) the presence
in abundance of widespread species much rarer elsewhere; (5)
the relative abundance of the various species comprising the
florula; (6) the general physiognomy of the vegetation ; (7) the
presence of special characteristic plant-associations; (8) the
differences in widespread plant-formati ons ; (9) the agriculture,
horticulture, and introduced plants of the proposed area."

As pointed out in the original article, the "actual boundaries
of many of the districts are extremely hard to fix and in no few
cases must always be artificial." This leads up to an inquiry as
to how far, based on four years' trial of these districts, sup-
plemented by a good deal of field-work in the South Island, the
boundaries, etc., of these districts should be modified.

Taking the North Island first of all, it is a moot point
whether or not latitude 36deg. S., a most critical point, as
explained later, should not be made a boundary-line and the area
to the north be constituted either a district or a subdistrict.
As for the boundary of the South Auckland District the Mokau
River would probably be more natural than that shown on the
map. The Volcanic Plateau and, East Cape Districts seem
natural enough, but their limits require extended study in the
field. Probably the southern boundary of the East Cape
District should be moved further to the south. The southern
part of the North Island offers exceptional difficulties. It can-
not be right to treat it as one district, and yet, according to the
present arrangement, the Egmont-Wanganui district is based
chiefly on negative characters and on the vegetation rather than
the flora. A far more exhaustive botanical survey of the whole
area, especially west of the Tararua — Ruahine Mountains, is
required and many local lists of species must be compiled, and
descriptions of the plant-associations writtten, before enough
material is available for comparative purposes.

Coming now to the South Island, the southern boundary of
the Marlborough Sounds subdistrict is unsatisfactory. The
Wairau river forms the natural boundary between the forested
area of the north and the tussock-grassland of the south. But
here comes in a great difficulty. That is, what is to be done
with the high-mountain vegetation of the Dun Mountain and the
mountains drained by the R. Pelorus and the R. Wairau from
Mt. Patriarch eastwards. Their flora cannot possibly be united
with that of the Tararua Mountains, and it is not really a part
of that of the North-eastern Botanical District proper, neither
can it be united to the high-mountain flora of the North-western
Botanical District. On the other hand, the lowland flora, as
bounded by the Wairau River, might quite well come into the
Marlborough Sounds Subdistrict. This critical matter is one
for Nelson botanists to investigate, and its solution could well
be undertaken by the Cawthron Institute. The North-western
and North-eastern Botanical Districts are well-marked, as may

11

be seen from the lists given under another head, but their south-
ern and their common boundaries require exhaustive study. The
same criticism is even more true for the Eastern and Western
Districts. Probably the Mackenzie Plains and some of the area
adjacent thereto should be added to the North Otago Botanical
District. The position of Banks Peninsula is somewhat doubt-
ful. Laing 1 1 would include it with the North-eastern District
on account of its forest-flora resembling that of the Seaward
Kaikoura Mountains rather than that of the foot-hills of
the Canterbury Plain. But it must not be forgotten that
Nothofagus is an important genus in the upper part of the
Kaikoura forest and that the general construction of the latter
forest is not similar to that of Banks Peninsula, while the
Kaikoura forest contains some species absent on Banks Penin-
sula, notably: Astelia Solandri, Melicope ternata, x M. Ralphii
and Metrosideros scandens. Also the Podocarpus dacrydioides
forest of the Canterbury Plain is similar to that of Banks
Peninsula. Be the above as it may, Banks Peninsula should be
distinguished from the Eastern Botanical District in general, and
made into a subdistrict distinguished by its forest; its local
endemism of Anisotome sp. near A. Enysii, Celmisia Mackaui,
Senecio saxifragoides, Veronica Lavaudiana and V. leiophylla
var. strictissima J 2 ; its being the southern limit on the east of a
number of northern New Zealand plants; its luxuriant fields of
Dactylis glomerata harvested for seed and its mild climate allow-
ing the cultivation of many garden-plants not hardy in the
Eastern Botanical District generally.

3.— SOME OUTSTANDING FEATURES OF PLANT-
DISTRIBUTION IN NEW ZEALAND.

(a) Cook Strait not a Barrier to Plant-distribution.

At first thought it would seem that Cook Strait would have
been a barrier to the movements of species, and that the flora
and vegetation on its opposite sides would be strikingly dis-
similar. So little is this the case, as far as the coastal and
lowland vegetation are concerned, that the associations of these
areas present no differences of moment. The lowland Notho-
fagus forest in the vicinity of the Marlborough Sounds, and near
the City of Nelson, strongly resembles that of the eastern side
of the Hutt Valley (Wellington). The forest-floras in general
are almost identical. To come to a few details: the shore
veronica of both areas is Veronica salici folia var. Atkinsonii;
Hymenanthera obovata of coastal rocks occurs on both sides
of the Strait and also on Kapiti Island; Phormium Colensoi is
common on rocks near Island Bay (Wellington) and in a similar
situation at Queen Charlotte Sound; Cassinia leptophylla

11- "The Vegetation of Banks Peninsula, with a List of Species (Flowering-
plants and Ferns)." Trans. N.Z. Inst., vol. li, 1919, p. 370.

12- V. leiophylla Cheesem. var. strictissima (Kirk), Cockayne comb. nov.=
V . parviflora Vahl var. strictissima, Kirk in Trans. N.Z. Inst., 28 (1*96), 527.

12

becomes a bad weed in both areas after forest is destroyed (see
Fig. 6) ; Dysoxylum coastal-forest is a well-marked feature;
Muehlenbeckia Astoni — a plant of extremely limited distribution
— occurs at the mouth of the R. Ongaonga (Wellington) and
near the mouths of the Awatere and Flaxbourne Rivers (Marl-
borough) ; finally, the introduced Glaucium flavum occurs on
shingly beaches on the northern shores of Cook Strait and at
the mouth of the Awatere. To be sure there are some differ-
ences of minor importance One of some moment, however,
may be cited. This is the abundance of Arthropodium cirratum
on coastal rocks in the Marlborough Sounds; in the North
Island, I do not know of its occurrence except in the Auckland
Botanical Districts. Other localities for this species are
Stephen's Island (Cook Strait), Takaka and West Wanganui
Inlet (Nelson).

Against all that has just been said, it may be urged that
Cook Strait has proved a formidable barrier for the high-
mountain plants to overcome as proved by the much smaller
high-mountain flora of the North Island. But I may again
point out that the poverty of this flora is due in part, at any
rate, to the limited space available for alpine and subalpine
plants in the North Island. Certain common North Island
subalpine plants are present, however, only on the Nelson
mountains, but do not extend further south. Such are Celmisia
hieracifolia, Leucogenes Leontopodium, Ranunculus insignis
.(see Fig. 8), R. geraniifolius and Senecio Adamsii. To these
may perhaps be added Senecio elaeagnifolius var. Buchanani
which occurs on Mount Stokes (Marlborough Sounds) and
Ourisia macrophylla which extends south as far as the Seaward
Kaikoura and Hanmer Plains mountains. The North Island
high-mountain flora consists of about 175 species and of these
about 142 are also South Island species. Probably for a long
period North and South Island mountains have been separated
by forest, so that the settlement upon a North Island mountain
of a species coming from the south would be a matter of
difficulty.

(b) The relation of latitude to distribution.

(1) GENERAL.

New Zealand proper extending, as it does from about latitude
34deg. S. to about latitude 47deg. S., offers an excellent example
of the effect of change of temperature upon the distribution of
the lowland-coastal flora and vegetation. It will be seen from
what follows that near certain parallels of latitude there are
critical belts on, or near which, species more or less common
further north come to a halt. This does not say that such
species could not exist further to the south. On the contrary,
cultivation has proved that many of them are hardy in gardens,
etc., far to the south of their natural area of distribution. The
kauri (Agathis australis), the puriri (Vitex lucens), the nao
(Colensoa physaloides) and the puka (Meryta Sinclairii) are
cases in point. Nevertheless, it is well-known that many —

13

perhaps most — species of New Zealand vascular plants, even
those of the high mountains, will only tolerate a comparatively
small amount of frost, while not a few, even where they grow
wild, are very near their frost-tolerating limit. It may be
asserted then, with some degree of confidence, that the climate of
these latitudinal boundary-lines, dealt with below, represents the
minimum heat-requirement of the species which have their
southern limit of distribution in their vicinity. In certain cases
this is most likely not the sole deciding factor, but each species
would require to be dealt with on its merits. Nor must it be
forgotten that the species forming an association are subject to
competition and that this also helps to decide what is the mini-
mum heat-requirement. The critical parallels of latitude are,
36deg.S.,, SSdeg.S., and 42deg.S. This latitudinal distribution
concerns only the lowland-coastal flora, the distribution of the
high-mountain flora is a more complex matter, for a greater
variety of ecological factors is concerned, while the heat-factor
is equalized at different latitudes by the gradual lowering in
altitude of the various vertical belts of distribution in proceed-
ing from north to south. In other words, latitude plays a far
smaller part with regard to the high-mountain flora than it does
with that of the coast or the lowlands. There is probably no
high-mountain plant that, given its other ecological require-
ments, especially its water requirement, could not flourish on any
New Zealand mountain irrespective of latitude, but, in the low-
lands some can grow only under special conditions. This is
well-known to the cultivator of New Zealand alpine plants who
can grow some with the greatest ease and others with extreme
difficulty, while some apparently are impossible to cultivate at
all.

(2) LATITUDE 36° S. AS A PHYTOGEOGRAPHICAL BARRIER.

A considerable number of species occur only to the north
of lat. 36deg.S. ; and, as some of these are restricted to the far
north of the island and others do not nearly reach the above
parallel, this is not so much a "barrier" as a dividing line
between two phytogeographical divisions. This was originally
pointed out by Colenso in his classical essay13 written so early
as 1865, and he distinguished north of that latitude two botani-
cal areas, namely, "The Northern Area" (34deg.S. to SSdeg.S.)
and "The Bay of Islands area" (SSdeg.S. to 36 deg.S.). The
following is a list of the species: — (Lycopodiaceae) Lycopodium
Drummondii; (Filices) Asplenium japonicum, Todaea barbara;
(Gramineae) Microlaena Carsei; (Cyperaceae) Cladium
complanatum, Lepidosperma fill forme; (Centrolepidaceae)
Hydatellainconspicua; (Orchidaceae)1* Thelymitra intermedia,

13. On the Geographic and Economic Botany of the North Island of New
Zealand. Trans. N.Z. Inst., vol. i, 2nd Ed., pp. 233-283, 1876 (written for the
New Zealand Exhibition, 1865, and published in the 1st Ed. of the Trans. N.Z.
Inst in 1870).

14. When the distribution of the terrestrial orchids of New Zealand is better
known, doubtless some of the orchids listed here will be found to have a wider
range.

14

T. Matthewsii, Caladenia exigua, Chiloglottis formicifera, Cory-
santhes Matthewsii, C. Carsei; (Piperaceae) Macropiper excel-
sum var. major on the Poor Knights Islands; (Loranthaceae)
Phrygilanthus Raoulii; (Lauraceae) Cassytha paniculata;
(Crassulaceae) Crassula pusilla; (Pittosporaceae) Pittosporum
pimeleoides vars. major and reflexum; (Cunoniaceae) Ackama
rosaefolia; (Malvaceae) Hibiscus diversifolius, (Halorrhaga-
ceae) Halorrhagis cartilaginea, H. incana; (Araliaceae)
Pseudopanax Gilliesiana; (Cornaceae) Corokia Cheesemanii;
(Epacridaceae) Leucopogon Richei—a\so on the Chatham
Islands; (Loganiaceae) Geniostoma ligustri folium v&r.crassum;
(Scrophulariaceae) Veronica speciosa var. brevifolia, V.
Bollonsii — on the Poor Knights Islands; V. ligustri folia,
V. acutiflora; (Rubiaceae) Coprosma neglecta; (Campanula-
ceae) Colensoa physaloides — also on the Three Kings Islands;
(Compositae) ; Lagenophora pinnatifida var. tenuifolia, Olearia
angulata; Celmisia Adamsii var. rugulosa — hardly a case in
point ; Cassina amoena.

(3) LATITUDE 38° S. AS A PHYTOGEOGRAPHICAL BARRIER.

Some 56 species of which 45 are common, or fairly common
plants, either do not quite reach latitude 38deg.S., or go beyond
it only for a comparatively short distance. The following is a
list of the species: — (Filices) Pteris comans, Lygodium articu-
latum, (Lycopodiaceae) Phylloglossum Drummondii, Lycopo-
dium densum, Psilotum triquetrum; (Taxaceae) Phyllocladus
glaucus; (Pinaceae) Libocedrus Doniana, Agathis australis;
(Gramineae) Paspalum scrobiculatum, P. distichum, Stipa
teretifolia; (Cyperaceae) Schoenus Carsei, Cladium Huttoni,
Lepidosperma laterale; (Restionaceae) Sporodanthus Traversii;
(Orchidaceae) Thelymitra pulchella, Prasophyllum pumilum,
Caleana minor, Pterostylis barbata; (Proteaceae) Persoonia
torn; (Lauraceae) Beilschmiedia tar air e, Litsaea calicaris;
(Saxifragaceae) Ixerba brexioides, Quintinia serrata; Pittos-
poraceae) Pitttosporum Huttonianum, P. virgatum, P.
crassifolium; (Cunoniaceae) Weinmannia sylvicola; (Rutaceae
Phebalium nudum; (Rhamnaceae) Pomaderris elliptica, P.
Edgerleyi; (Malvaceae) Hoheria populnea (H. populnea var.
vulgaris of the "Manual") ; (Violaceae) Melicytus macrophyl-
lus.1 8 ; (Myrtaceae) Metrosideros albiflora, M. diffusa, M.
tomentosa; (Araliaceae) Pseudopanax discolor, P. Lessonii, P.
crassifolium var. trifoliolatum; (Cornaceae) Corokia buddleo-
ides; (Epacridaceae) Dracophyllum Sinclairii, Archeria race-
mosa; (Sapotaceae) Sideroxylon novo-zelandicum; (Verbe-
naceae) Vitex lucens, Avicennia officinalis; (Scrophulariaceae)
Veronica macrocarpa, V. diosmaefolia, V. pubescens; (Lentibu-
lariaceae) Utricularia delicatula; (Rubiaceae) Coprosma arbo-
rea, C. spathulata; (Compositae) Olearia albida, Celmisia
Adamsii — the type, Cassinia retorta, Siegesbeckia orientalis,
Bidens pilosa and Senecio Banksii.

is. Cheeseman, " Manual of the New Zealand Flora," 1906, p. 47, refers a plant
Collected near Dunedin to this species,

15

The vegetation, too, north of lat. 38deg. S., right to the
North of the North Island is distinguished by certain distinct
plant-associations, of which the most striking are Kauri (Aga-
this) forest (see Fig. 7) mangrove (Avicennia) salt-swamp the
shrub and bog associations of the barren clay gumlands, and the
pohutakawa (Metrosideros tomentosa) association of sea-cliffs.
Coastal forest, coastal scrub and stable dune associations are also
of a special character. Natural grassland is absent, its place
being occupied by shrubland.

(4) LATITUDE 42°S. AS A PHYTOGEOGRAPHICAL BARRIER.

In the following list North Island species which extend to
Banks Peninsula on the east and beyond the Taramakau River
on the west are excluded. On the other hand, species which
have, so far, been recorded only from the extreme northern parts
of the South Island are included. The phytogeographical divid-
ing-belt is therefore of considerable width. The list given below
emphasises what has been already stated concerning the close
relationship between the adjacent lowland and coastal floras of
the North and South Islands. The following is the list of
species: (Filices) Adiantum aethiopicum, A, hispidulum, Pel-
laea falcata, Pteris tremula, P. macilenta, Blechnum filiforme, B.
Fraseri, Doodia media, Asplenium umbrosum, Arthropteris
tenella, Poly podium dictyopteris; (Lycopodiaceae) Lycopodium
cernuum; (Taxaceae) Phyllocladus trichomanoides ; (Gram-
ineae) Spinifex hirsutus, Dichelachne sciurea, POOL anceps var.
elata, Bromus arenarius, Agropyron multiflorum; (Cyperaceae)
Elaeocharis neo-zelandica, Schoenus brevifolius, S. tendo,
Cladium capillaceum, Gahnia setifolia, G. pauciflora, G.
xanthocarpa; (Liliaceae) Astelia Banksii, A. Solandri, A. triner-
via, Arthropodium cirratum; (Orchidaceae) 16 Prasophyllum
rufum, Pterostylis trullifolia, P. puberula, Acianthus Sinclairii,
Calochilus paludosus, Corysanthes Cheesemanii; (Piperaceae)
Peperomia Urvilleana; (Proteaceae) Knightia excelsa; (Poly-
gonaceae) Muehlenbeckia Astoni; (Magnoliaceae) Drimys
axillaris; (Monimiaceae) Laurelia novae-zelandiae ; (Lauraceae)
Beilschmiedia tawa; (Cruciferae) Lepidium incisum; (Pittos-
poraceae) Pittosporum corni folium; (Leguminosae) Car-
michaelia australis, C. odorata; (Rutaceae) Melicope ternata,
x M. Mantellii; (Meliaceae) Dysoxylum spectabile; (Tiliaceae)
Entelea arborescens; (Malvaceae) Hibiscus trionum; (Viola-
ceae) Hymenanthera obovata17 ; (Thymelaeaceae) Pimelealon-
giflora; (Myrtaceae) Metrosideros Parkinsonii 1 8 , M. Colensoi,

!6. Some of these orchids may extend much further south on the west of the
South Island since the orchid florula of the Western Botanical District is com-
paratively unknown. Mr. W. Townson collected orchids most assiduously in the
neighbourhood of Westport, hence the number of species recorded. So, too, for
the neighbourhood of Kaitaia (Northern Auckland), thanks to the labours of the
late Mr. R. H. Matthews and Mr. H. Carse.

17- Excluding from the conception of the species the Castle Hill (Canterbury)
plant.

lg- Recently discovered by W. R. B. Oliver on Great Barrier Island — its only
gtation north of Cook Strait, so far as is known.

16

M. robusta, Myrtus bullata, x M. Ralphii, Eugenia maire;
(Halorrhagaceae) Myriophyllum robustum; (Epacridaceae)
Epacris pauciflora, Dracophyllum lati folium; (Oleaceae) Olea
Cunninghamii, O. lanceolate, O. montana; (Myrsinaceae)
Rapanea salicina; ( Logariiaceae) Geniostoma ligustrifolium
(Scrophulariaceae) Veronica speciosa, V. salicifolia var.
Atkinsonii, V. parviflora, V. gracillima, Euphrasia cuneata;
(Rubiaceae) Coprosma retusa, C. tenuicaulis, Nertera Cunning-
hamii; (Caprifoliaceae) Alseuosmia quercifolia; (Cucurbita-
ceae) Sicyos australis; (Compositae) Olearia Cunninghamii,
Gnaphalium subrigidum, Cassinia leptophylla, Brachyglottis
repanda.

This list together with that given for latitude 38deg., almost
exhaust the North Island element of the New Zealand forest
flora19, but Banks Peninsula is the southernmost halting-place
for a few more species (e.g., Alectryon excelsum, Adiantum
fulvum, Corynocarpus Io2vigata, Dodonoea viscosa, Griselinia
lucida, Leucopogon fasciculatus, Macropiper excelsum, Mariscus
ustulatus, Rhopalostylis sapida, Tetrapathcea australis and
Zoysia pungens. On the west, those most common species of
North Island forests — Astelia Cunninghamii, Metrosideros
florida and M. scandens are a characteristic feature of the
forest of the Western Botanical District as far south as Okarito,
at any rate ; so too is Freycinetia Banksii, which extends further
south into the Fiord Botanical District. The North Island
tree-ferns, Cyathea Cunninghamii and Dicksonia lanata, are
also found in some localities of the Western District.
Hedycarya arborea, on the east, has its southern limit on Banks
Peninsula, but on the west it extends as far south as Preserva-
tion Inlet.

(c) The effect of the Southern Alps and the Coastal Mountains of
North-western Nelson on plant-distribution.

The mountains situated at so short a distance from the
Tasman Sea near the west coast of the South Island cause the
moisture-laden westerly winds to deposit nearly all their
moisture, so that an extremely wet climate extends from the
coast-line to a definite point on the eastern side of the actual
Divide. This area in the lowland, montane, and lower-subalpine
belts is clothed with a dense forest-mass, but, at its eastern
boundary at a point marjdng the average limit of the western
downpour, it gives place, all on a sudden to tussock-grassland.
Frequently the rain extends to the very margin of the forest,
while less than a mile to the eastward the sun is shining, or,
at most, a few ^rops of rain are carried by the furious gale
which nearly always accompanies the downpour. So sharp is
this distinction between western forest and eastern grassland
from the north of the South Island to the forest of Southland
that hardly a single tree invades the grassland, but the forest
stands a dense, dark barrier with clean-cut margin, whence

19. Of course certain species in these lists do not belong to the forest flora.

Photo., F. G. Gibbs.

FlG. 8: Ranunculus insignis, a large-leaved sub-alpine herb (also occurring in the
North Island), growing on Mount Arthur plateau.

Photo., L. Cockayne.

FlG. 9 : View of piece of upper sub-alpine forest of Westland. In centre
Dracophyllum Traversii, and below it SuMonia divaricata.

17

extends eastwards the tussock-grassland. The change in the
physiognomy of the vegetation is instantaneous — there is no
transitional phase.

This sudden change in rainfall, and the number of rainy
days, is not reflected merely by the forest, or the tussock-grass-
land, but it greatly affects the high-mountain vegetation also.
On the west dense subalpine-scrub is common, — on the east it
is absent, or in isolated patches; fell-field and unstable debris-
slopes with their special plants are a feature of the east,
whereas herb-field is the physiognomic subalpine plant-
association of the west; extreme xerophytes (both herbs and
shrubs) are characteristic of the eastern mountains and
mountain- valleys (e.g. — Aciphylla Dobsoni, Carmichaelia
Petriei, Clematis afoliata, Colobanthus brevisepalus, Coprosma
brunnea, Helichrysum coralloides, H. depressum, Hymenanthera
dentata var. alpina, Lepidium sisymbrioides, Muehlenbeckia
ephedroides, Myosotis uniftora, Olearia coriacea, Pimelea sericeo-
villosa, Poa aciculari folia, Raoulia Parkii, Sophora prostrata
and Veronica epacridea) but, on the west, though xerophytes are
far from lacking, there are more mesophytes and a few specially
large-leaved herbs (e.g. — Anisotome capillifolia, A. Haastii,
Ourisia macrocarpa vars. calycina and cordata, Ranunculus
insignis (see Fig. 8), and R. Lyallii) ; the east is the home of
the majority of the high-mountain species of Veronica; the
upper subalpine forest of the west may consist of shrubby
Compositae, Libocedrus Bidwillii, Podocarpus Hallii, Dacrydium
biforme and Dracophyllum Traversii (see Fig. 9) : whereas, on
the east, forest is confined to gullies and shady slopes and usually
consists of Nothofagus cliff ortioides with but little undergrowth.

East and west, though possessing many species in common,
have each a rich locally-endemic element. As an example of
this the locally-endemic species of the North-eastern and North-
western South Island Botanical Districts may be cited.

The endemics of the North-eastern District are the follow-
ing: (Ranunculaceae) Ranunculus lobulatus; (Rosaceae) Geum
divergens; (Leguminosae) Carmichaelia Monroi (the type),
C. juncea var., Notospartium Carmichaeliae, Chordospartium
Stevensoni; (Onagraceae) Epilobium chloraefolium var. kai-
kourense, E. rostratum var. pub ens; (Convolvulaceae)
Convolvulus fracto-saxosa; (Boraginaceae) Myosotis Cockaynei,^
M. Laingii, M. saxatilis; (Gentianaceae) Gentiana Astoni
(Scrophulariaceae) Veronica rupicola, V. decumbens, V.
Hulkeana; (Campanulaceae) Wahlenbergia flexilis, W.
Matthew sii, W. cartilaginea ; (Compositae) Olearia insignis,
O. coriacea, Celmisia Cockayniana, C. Monroi, Haastia pulvinaris,
H. recurva var. Wallii, Gnaphalium nitidulum, Raoulia cinerea,
Helichrysum Sinclairii, H. coralloides, H. Fowerakeri, Cassinia
albida vars. typica and canescens, Abrotonella Christensenii,
Senecio Monroi, S. Christensenii.

The following are the local endemics of the North-western
District: — (Cyperaceae) Carex trachycarpa, C. Gibbsii; (Orchi-

18

daceae) Townsonia deflexa; (Ranunculaceae) Ranunculus
verticillatus; (Magnoliaceae) Drimys Traversii; Pittospora-
ceae) Pittosporum Dallii; (Leguminosae) Carmichaelia Fieldii;
(Umbelliferae) Aciphylla Hookeri, A. indurata, A. trifoliata,
Anisotome diver si folia; (Epacridaceae) DracophyllumTownsoni,
D. pubescens; (Boraginaceae) Myosotis angustata, M. concinna;
(Loganiaceae) Mitrasacme montana var. Helmsii; (Gentian-
aceae) Gentiana filipes, G. gracilifolia, G. vernicosa;
(Scrophulariaceae) Veronica Townsoni, V, diver gens, V.
albicans 20, V. coarctata; Euphrasia Cheesemanii; (Com-
positae) Celmisia rupestris, C. Gibbsii, C. Morgani, C. parva,
C. dubia, C. semicordata, C. cordatifolia, C. Dallii, C. lateralis,
Senecio glaucophyllus, S. laxifolius, S. Hectori.

If the species of the two previous lists be compared as to
their habitats it will be seen that 22 of the North-eastern
endemics are rock or rock-debris plants, whereas the North-
western endemics are mostly forest, herb-field, or scrub species.
Many of the rock plants of the North-eastern district, together
with certain more wide-spread species, form one of the most
clearly-defined plant-associations of the New Zealand Region,
the composition of which at its full development is as follows : —
Angelica montana, Anisotome aromatica var., A. filifolia,
Celmisia Monroi, Clematis afoliata, Coriaria sarmentosa var.,
Linum monogynum, Olearia insignis, Phormium Colensoi,
Senecio Monroi, Veronica Hulkeana and Wahlenbergia
Matthewsii. This association is confined to the drier parts of
the district, with the addition of the seaward Kaikoura moun-
tains—a wet area — but does not extend into the Eastern
Botanical District, but halts all on a sudden, although the habitat
it affects is everywhere in abundance. The characteristic
member of the association (Olearia insignis) — a most aberrant
member of the genus, probably of generic distinctness, with no
near relatives in the New Zealand region, or elsewhere — should
theoretically be of great age and so of wide-spread distribution,
yet the contrary is the case.

(d) The effect of the frequent south-west wind on plant-distribution
in the South Island and Stewart Island.

On Stewart Island, and for a certain distance northwards in
the south of the South Island, the downpour which so often
accompanies the frequent south-westerly gales favoured the
establishment of forest on such parts of the lowland and mon-
tane belts as the edaphic and other climatic conditions were
favourable. Much of the great South Otago forest has been
destroyed as settlement progressed, but that of Stewart Island
is virtually intact. On the mainland here were both taxad and

2°- V. albicans may be only a synonym for V. carnosula. It is related to
V, ample xicaulis, a species hitherto only recorded from the Rangitata river-basin.
There are other glaucuous-leaved veronicas more or less closely related to
V. albicans, apparently peculiar to this district, but they have hitherto been
referred to V. pinguifolia, a very large aggregate species consisting of many most
distinct microspecies.

19

Nothofagus forests, but this genus, strange to say, is absent in
Stewart Island, nor does it occur in the New Zealand sub-
antarctic islands.

The low temperature of the atmosphere during a south-west
gale, the cold rain and the frequent cloudy skies of the South
Otago and Stewart Districts are strongly reflected in the vegeta-
tion. Thus sphagnum bogs are a striking feature in many
places; there is a cold, "sour" soil which favours the establish-
ment of tall tussock-grassland of Danthonia Raoulii var. rubra
which is accompanied by certain species generally confined to
the high mountains elsewhere (e.g., Astelia montana var.
Blechnum penna marina, Cyathodes empetrifolia, Gaultheria
depressa, G. perplexa, Herpolirion novae-zelandiae, Oreostyli-
dium subulatum, Pentachondra pumila, Raoulia glabra. Other
high-mountain plants also descend to sea-leval, and this is
especially the case in Stewart Island, where the following have
been noted : Astelia linearis, Caltha novae-zelandiae, Carpha
alpina, Celmisia argentea, Coprosma repens, Donatia novae-
zelandiae, Dracophyllum Pearsoni, D. politum, Gaimardia
ciliata, Geum leiospermum, Olearia Colensoi, Oreobolus
pectinatus, Senecio elaeagnifolius, S. Lyallii.

In the high mountains the abundant south-west rain is re-
flected by the presence of extensive herb-fields — a spectacle
altogether different from the tussock-grassland of the dry North
Otago Botanical District, where Poa intermedia dominates. At
that point, where the Old Man Range is at the limit of the south-
westerly rain, its rich vegetation and florula stand out in
striking contrast to the adjacent hills and mountains of the
North Otago Botanical District now without tussocks for hun-
dreds of feet, their main vegetation mats of Raoulia lutescens.
Originally these hills were tussock-clad, but they never bore the
abundant collections of alpine herbaceous and semi-woody plants
which distinguish the flat summit of the Old Man Range, while
their present depletion bears striking testimony to the effect of
the south-west rain upon plant-distribution.

The climate of the South Otago Botanical District has
favoured a certain amount of local endemism, but as this climate
is somewhat similar to that of the Fiord Botanical District
they possess many species of restricted distribution in common
(e.g., Aciphylla pinnatifida, Anisotome intermedia, Celmisia}
argenta, C. Hectori, C. lanceolata, C. ramulosa, C. verbascifolia,
Dracophyllum Menziesii, Gentiana saxosa, Olearia moschata,
Ourisia prorepens, Ranunculus Buchanani, Senecio revolutus,
Veronica dasyphylla, V. Hectori, V. Petriei.

Stewart Island has a fairly strong local endemism (19
species) made up as follows: — (Gramineae) Danthonia
pungens; (Cyperaceae) Uncinia pedicellata, U. compacta var.
caespitiformis, Carex longiculmis; (Liliaceae) Chrysobactron
Gibbsii; (Ranunculaceae) Ranunculus Kirkii, R. Crosbyi;
(Umbelliferae) Schizeilema Cockaynei, Aciphylla Traillii,

20

Anisotome intermedia var. oblongi folia, A. flabellata (Epacri-
daceae) Dracophyllum Pearsoni; (Gentianaceae) Gentiana
Gibbsii; (Scrophulariaceae) Veronica, Laingii, Ourisia modesta;
(Compositae) Olearia divaricata, Celmisia glabrescens, Raoulia
Goyeni, Abrotonella muscosa.

An interesting point is that, notwithstanding the Stewart
flora being separated from the South Island by 15 miles of sea at
the nearest point, it has only 6 per cent, of its florula locally en-
demic, much less than might be expected when the florulas of the
North-western and North-eastern Botanical Districts are con-
sidered, the former with 4 per cent., and the latter with 4.4 per
cent, of locally endemic species. Again, the Chatham Islands,
situated 500 miles from the New Zealand mainland, have only 13
per cent, of locally-endemic species.

(e) Effect of altitude upon plant distribution.

It has already been noted that New Zealand has a high-
mountain flora very distinct from that of the lowlands in that
out of its 950 species no less than 500 are entirely mountain-
dwellers, while 100 others descend to the lowlands only under
exceptional circumstances. These high-mountain species are not
arranged haphazard, but each has its special altitudinal range;
while, as in mountains everywhere, the flora as a whole is ar-
ranged in altitudinal belts. Thus, beginning at sea-level, there
is the lowland belt which extends to an altitude of about
1000 feet throughout most of the South Island, but in the
North Island it will be from 500 to 1000 feet higher.
Above the lowland belt comes the montane belt, and it
extends upwards for 2000 feet. Then the next thousand feet is
the lower subalpine belt, above which for one thousand feet is
the upper subalpine belt, and above this, up to the limit of vege-
tation, is the alpine belt. These figures are altogether approxi-
mate, for latitude, aspect and climate all affect altitudinal distri-
bution, so that there is no uniformity even on any one mountain.
This is evidenced by the sheep-farmer with his "summer" and
"winter" country, and in this he recognises the fundamental fact
regarding vertical distribution, namely the average length of
time that the snow lies on the ground during the cold months
of the year. Thus the alpine belt is that area where the winter
snow lies for some six months; on the subalpine belt it may lie
for two months or so in its upper part and a week or two in its
lower part ; on the montane belt the snow will lie usually only a
few days ; while on the lowland belt there may be snow only occa-
sionally, or perhaps not at all. These facts regarding the effect
of snow stand out clearly from an examination of the vegetation
of gullies and hollows where the snow lies for a long time — far
into the summer it may be. A few examples may be of interest.

On Mount Egmont, in the subalpine belt, there are two
well-marked plant-formations in close proximity; the one tall
tussock-grassland of Danthonia Raoulii, var. rubra, the tussocks
densely crowded, but with here and there open spaces occupied
by a turf of prostrate herbs, semi-woody plants and shrubs ; the

21

other, and here the snow lies long, is herb-field with the vegeta-
tion reduced to a turf, so that plants of the mat-form are mats
no longer, e.g., Helichrysum prostratum has its densely-leafy
silvery shoots dotted about, but not spreading and forming a
thick mat. Here and there are very small shrubs of Veronica
buxifolia.

On Mount Ollivier (Sealey Range) at an altitude of 4200
feet and upwards are here and there hollows where the snow
lies until the beginning of February, and later. Such hollows,
as the snow melts, are bathed with ice-cold water for several
days at a time. Their vegetation differs from that of the
adjoining slopes where the snow melts much earlier. At about
4300ft. there are, in such hollows, mats of Danthonia oreophila
var. elata, perhaps lOin. thick, and so dense that hardly any other
plants can gain a footing. At a higher altitude there are masses
of Astelia nivicola flattened to the ground, and cushions of the
silvery Celmisia Hectori, which apparently, on this mountain is
confined to this station. On the adjacent slopes is tall tussock-
grassland of Danthonia flavescens, and its accompanying plants.
At a higher altitude this tussock is replaced by D. crassiuscula.

On the flat summit of the Old Man Range (South Otago
Botanical District), at an altitude of 5000 feet and upwards,
the winter-snow lies long, and late snow-storms are frequent.
The ground, owing to the large quantity of snow-water, and the
powerful winds, is cut into hummocks some 9in. high, which
are covered with cushions of various species (e.g., Dracophyllum
muscoides, Phyllachne rubra, Raoulia Hectori, Hectorella
caespitosa, Veronica dasyphylla), and there is abundance of the
shrubby Celmisia ramulosa. After the snow melts the plants
are subjected to the full fury of the south-west gales — hence,
apart from the snow-covering, the prevalence of the cushion-
form.

A good many species are usually not met with until the line
marking the average limit of the winter snow is encountered.
Certain species of Celmisia, especially C. Haastii, and C. viscosa
are excellent indications of the snow-line, as, also in certain
parts of the North-eastern and North-western Botanical Dis-
tricts, the remarkable mat-forming grass, Danthonia australis.
Apart from the excess of ice-cold water which the plants are
obliged to tolerate, they are subjected to great pressure, and are
so flattened to the ground that one seeing them for the first time
could hardly believe they would recover. Plants forming dense
mats such as the two grasses mentioned above, are admirably
suited for their yearly burial, and their form may be considered
epharmonic.

(f) Effect of the edaphic factor on plant-distribution.

The edaphic factor, or to use Warming's term, "the nutrient
substratum 2 * ," is here used in the widest acceptation, and in-

21- Oecology of Plants, 1919, p. 40.

22

eludes not only the soil proper (from rock to ordinary soil), but
also water. With the soil are included the gases and water
which it contains. It is this edaphic factor, in conjunction
with the local climate, which chiefly governs the habitats of the
associations and the growing places of the species. A consider-
ation of plant-distribution on edaphic lines would open up the
whole of the ecology of New Zealand plants — a vast field as yet
but superficially explored. All that can be attempted here is the
statement of certain generalities together with an account of a
few cases where the effect of the soil is clearly apparent.

Generally, in New Zealand, the nature of the underlying
rocks has apparently but little influence on plant-distribution.
Rain-forest consists of the same species, at similar latitudes and
altitudes, whether the underlying rock be greywacke, volcanic,
limestone, or schist. That familiar sight, cliffs or steep banks
covered with the great leaves of Blechnum capense is in evidence
both on the calcareous mudstone declivities of the Wanganui
River and on ancient moraines of Southern Westland. The
Olearia insignis association, already referred to, thrives equally
well on either limestone or greywacke. There are fine forests
of Podocarpus totara both on the volcanic hills of Banks
Peninsula and on the pumice of the Volcanic Plateau.

Taking the case of limestone, it is true that a few species
(Asplenium lucidium var. anomodon, Anisotome palula, Senecio
glaucophyllus) have been recorded from limestone rocks only,
but so far as I know, limestone and greywacke, side by side, bear
exactly the same species. Still, more detailed research might
reveal certain constant distinctions between the vegetation of
limestone and that of non-calcareous rocks.

With one or two exceptions, to be noted presently, it is not
the chemical constitution of soils in New Zealand which deter-
mines the species, or plant-associations, but their physical
condition and, above all, their water-content. Thus stony river-
bed in the wet climate of Westland may carry forest, while in the
drier eastern climate there is merely an open vegetation of
species of Raoulia and Epilobium, to be finally replaced by low
tussock-grassland or xerophytic shrubland.

Stony debris slopes in the high mountains, so long as they
are not subject to an excessive rainfall, have a remarkable
number of plants in common — many of which, in their growth-
forms, stand in special categories to themselves. As with
forest in its area of distribution, so with tussock-grassland, that
of the South Island extends for hundreds of miles, covering
many classes of soils and exposed to many local climates, but
the dominant tussocks remain the same, e.g., Poa caespitosa
and Festuca novae-zealandiae, or where the soil is sour, usually
at higher altitudes, Danthonia flavescens or D. Raoulii in their
various varieties. In both these cases (forest and grassland)
the formation, as a whole, is governed by climate, but its changes
in structure depend upon the edaphic factor. The poa and fescue
tussocks, when both occur, indicate respectively the wetter and
the drier ground.

Photo., F. O. (iibb

FlG. 10: The sharp line of demarcation with Nothofagus forest on right and the
open, scanty vegetation of the Magnesian Mineral Belt, Nelson, on the left.

23

With regard to special edaphic examples three cases stand
out clearly — the associations of soil with excess of salt, the
vegetation of ground near fumaroles and the magnesian soil of
the Mineral Belt.

The leading salt-soil associations are salt-swamp, salt-
meadow, peaty salt-meadow (coastal moor), rocks exposed to.
sea-spray and salty patches in dry inland areas. The coastal
salt-associations consist of a small florula which extends with
but few changes throughout the three islands. A few of the
species are confined to salt ground, but most grow equally well
in non-saline stations, and some of these, which are character-
istic halophytes, extend inland, far from the sea, (e.g., Eryngium
vesiculosum, Leptocarpus simplex, Selliera radicans).

The association near hot-springs on the Volcanic Plateau is
shrubland with, as so frequently, Leptospermum ericoides domin-
ant. According to the amount of sulphur fumes and the excess
of certain salts, etc., in the soil, so do the species gradually
decrease until only Lycopodium cernuum, Leptospermum
ericoides (now prostrate) and Leucopogon fasciculatus (still
erect) remain.

The Mineral Belt is a narrow girdle of serpentine and
peridotite rocks, which in places crop out and in others lie as
debris, large and small, upon the surface-soil. It extends from
D'Urville Island to the Dun Mountain and beyond. It can be
recognised at a glance, and from a long distance, by its scanty,
stunted vegetation standing distinct from the adjacent forests.
So soon as the magnesian soil is encountered at its full strength
the neighbouring forest giv -s place all at once to shrubland or
tall tussock-grassland (see Fig. 10). Most of the species are
common New Zealand plants; but, if trees of the adjacent
forest, on the Mineral Belt are dwarfed at once to shrubs (e.g.,
the species of Nothofagus, Griselinia littoralis). The species
Myosotis Monroi and Pimelea Suteri are local endemics. The
rare species Notothlaspi australis and Colobanthus quitensis
are common. Many of the shrubs are pronounced xerophytes.

4._CONTINUOUS AND DISCONTINUOUS DISTRIBUTION.

The fact that species are arranged in associations most
diverse in character postulates the impossibility of the really
continuous distribution of any species. Continuity can only
mean that the associations in which the species in question
occurs extend for a longer or shorter distance, either latitudinally
or vertically, with breaks between. Species belonging to wide-
spread formations (e.g., dune, salt-swamp, salt-meadow, forest,
tussock-grassland, Leptospermum shrubland, Pteridium heath,
stony river-bed) may extend for long distances. Thus Scirpus
frondosus (dune), Leptocarpus simplex (salt-swamp), Selliera
radicans (salt-meadow), Dacrydium cupressinum (forest), Poa
caespitosa (tussock-grassland), Leptospermum scoparium
(shrubland), and Pteridium esculentum (heath) afford common
examples of continuous distribution. But these species (Poa,

24

caespitosa excepted) though extending from the north of the
North Island to Stewart Island are not by any means on an
equality in the power of extending their area, in the variety of
stations which they occupy, or in the actual distance they have
travelled. The extremely plastic L. scoparium easily comes
first both for vertical range and the number of associations to
which it belongs, while the Dacrydium is limited to lowland and
montane forest or occasionally lower subalpine scrub (Stewart
Island) and the Scirpus to unstable dunes. The length of
time it must have taken the latter to pass from dune to acme
must have been comparatively short to that required by a species
of equal latitudinal range, but which, in addition, is a member
of the lowland and high-mountain floras and belongs to several
plant-associations demanding special adaptations. Between
continuity and extreme discontinuity of distribution there is
every degree of transition. Each species has its northern,
southern, eastern, western and altitudinal limits. Taking the
517 purely lowland species, according to statistics I prepared
nearly seven years ago, but have not verified since, 249 occur in
all the mainland Botanical Provinces, but only 102 of these
extend to Stewart Island. A number of wide-spread species
have their northern limit in the South Auckland Botanical Dis-
trict, a rather remarkable fact when the capabilities for dispersal
of some of them are considered. Amongst such are various
ferns and lycopods (e.g., Hymenophyllum pulcherrimum, H.
unilaterale, Blechnum penna marina, Polystichum vestitum,
Lycopodium varium, L. fastigiatum and L. scariosum) but
notwithstanding their capacity for spreading by means of spores,
it must be pointed out that these are generally mountain
species or they appear to "prefer" more or less subantarctic
conditions. So, too, with most of the spermaphytes of the same
category, e.g., Phyllocladus alpinus, Enargea parviflora, Cordy-
line indivisa, Nothofagus Menziesii, Nothopanax simplex and
Coprosma foetidissima.

Coming now to some cases of isolation, or extremely re-
stricted distribution, the following may be noted : — Lycopodium
Drummondii occurs only in one station, a bog near Kaitaia
(North Auckland). This is also indigenous in Australia and
when the number of suitable stations for its occupation are
considered, and its power of far-dispersal by means of spores,
its isolation is remarkable. For some reason or other it is
most likely dying out. Logania depressa grows to the south-
west of the Kaimanawa Mountains. Evidently it is extremely
rare as it "has not been collected since its original discovery
by Colenso more than sixty years ago. It apparently has no
close New Zealand relatives, so it may be looked upon as dying
out. Veronica Astoni is confined to the Tararua Mountains
where it is abundant. As this species is closely related to the
more widely spread V. tetragona of the Volcanic Plateau, Kai-
manawa and Ruahine Mountains, it must be considered of recent
origin. — Coprosma Buchanani occurs only in a few places on
the shores of Cook Strait. Appaiently it has no near relatives,

25

and so may be considered of considerable age. — Pittosporum
Dallii is restricted to one locality in the North-western district ;
it differs considerably from any other known species of the
genus; here again if strong individuality be a test of age, the
species should be a relict. — Cassinia amoena and Halorrhagis
cartilaginea are confined to the North Cape Peninsula; in this
case extreme youth is suggested especially for the latter, origin-
ally considered by Cheeseman a variety of H. erecta. Helichry-
sum dimorphum is recorded from only one portion of the
Waimakariri river-basin ; this differs from all the other species
in that it is a thick-stemmed liane. Myosotis albo-sericea is
only known from one locality in the North Otago District; it
is a xerophytic rock-plant allied to the much more widely spread,
but not common, M. Goyeni; this may be a young species.
Lepidium Kirkii a species not closely allied to any other is
confined to salt patches on the Maniototo Plain. Poa pygmaea,
another most distinct plant is confined to the elevated plateau of
the Mount Pisa Range. Notospartium Carmichaeliae, a com-
mon plant within its range extends only from the R. Waihopi
to the R. Awatere, where it is rare; further south it is repre-
sented by N. torulosum or perhaps by this and another species ;
the genus itself extends at wide intervals from the Waihopi to
Peel Forest. Veronica amplexicaulis is confined to the
Rangitata river-basin, where there is more than one variety;
it is related to the V. pinguifolia series and like many species of
the genus in New Zealand is probably young. If the special
ecology of most of the above species be considered it can be
seen they are not specially adapted for the locality, or even the
exact habitat they occupy.

There remain now to be noted only a few examples of ex-
treme discontinuous distribution. The following list does not
aim at completeness. After the name of the species is given its
distribution, its habitat is in brackets.

Angelica trifoliolata (sphagnum bog) Mount Torlesse and
neighbourhood of Lake Tennyson — Celmisia Traversii (herb-
field and fell-field), common in parts of the North-eastern and
North-western Districts and not again met with till in the south
of the South Otago District. Drosera pygmaea (wet ground),
North Auckland District in far north, Waimarino Plain and
the Bluff Hill, at each in only a few stations. Leucopogon Richei
(heath), common on dry ridges in the Chatham Islands and in
the North Auckland District, but rare. Metrosideros Par-
kinsonii (forest) , common in west of the North-western District
and rare on the Great Barrier Island. Pittosporum patulum
(forest) North-western District, but not common, and rare near
Lake Hawea. Pittosporum obcordatum (forest) Banks Penin-
sula but now probably extinct, extremely rare near Kaitaia
(North Auckland District). Myosotis Townsoni (herb-field),
west of North-western district and on Browning's Pass.
Ranunculus crithmifolius (Shingle-slip) mountains, Wairau
Gorge and Mount Arrowsmith Range. Sporodanthus Traversii

26

(Sphagnum bog), common in the Chatham Islands and near
Kaitaia and in the Waikato sub-district. — Suttonia chathamica
(forest and scrub), common in the Chatham Islands and in one
or two places in Stewart Island, but in small quantity. — Urtica
australis (seashore) Lord Auckland Islands, Antipodes Island,
Chatham Islands, and some of the small islands in Foveaux
Strait. — In all the above cases it seems safe to assume that the
species were at one time far more wide-spread and that the
actual dying-out of these species is being witnessed.

Such dying-out may actually be seen in progress in certain
cases in what are apparently climax associations. The follow-
ing two examples are of special interest. The common forest
of Stewart Island has now as its principal trees Weinmannia
racemosa and Dacrydium cupressinum. But at one time there
was evidently abundance of Podocarpus spicatus, for the remains
of this tree may be constantly seen enclosed by the base of the
Weinmannia trunk, which is composed of roots which originally
grew upon the fallen Podocarpus trees.

At the present time the Dacrydium cupressinum trees in the
Egmont National Park are being strangled by -the originally
epiphytic Metrosideros robusta, so that in a comparatively short
time that tree will have replaced the Dacrydium.

This matter of species apparently dying-out also receives
confirmation through the extreme rarity of certain species in
isolated localities, where, when the extreme difficulty of a new
member joining a well-established plant association is remem-
bered, they must be considered as almost defunct. The follow-
ing are examples; all are common, often exceedingly common,
in the North or South Islands (usually in both), and of
continuous distribution: In Chatham Island — Coprosma
robusta,, Discaria toumatou, Dodonaea viscosa, Leptospermum
scoparium (most ubiquitous of species!) Myoporum laetum,
Plagianthus divaricatus; in Lord Auckland Islands — Blechnum
fluviatile, Halorrhagis micrantha (especially suited for the wet
peaty soil), Fuchsia excorticata, Hemitelia Smithii, Samolus
repens var. procumbens, Uncinia uncinata; in Stewart Island —
Cordyline australis, Cyathea medullaris, Olearia ilicifolia,
Plagianthus betulinus, Podocarpus dacrydioides, Senecio
elaeagnifolius and Suttonia chathamica,

27

ADDENDA.

1. p. 12. Leucogenes Leontopodium, or a closely-related
plant, has been recently discovered on Mount Peel (Eastern
Botanical District) by Messrs. H. H. Allan and R. M. Laing,

2. p. 14. The following 5 species have also their southern
limit in the neighbourhood of latitude 38deg. S. : Cladium
articulatum, Clianthus puniceus, Dryopteris gongylodes, D.
parasitica and Fimbristylis dichotoma var. velata, but the last
three are confined to the neighbourhood of hot springs.

3. p. 15. The list of species Is restricted to those of the
lowland and coastal belts.

4. p. 19. Tall tussock-grassland with Danthonia flavescens
dominant is a common feature of the subalpine belt of the
South Otago Botanical District.

5. p. 23. On the Dunstan Mountains (Central Otago) the
usually coastal Selliera radicans is confined, not to salt soil, but
it forms a green turf on wet limestone rocks ; while, near Lake
Wanaka, it grows in soil always saturated with ice-cold water
issuing from an old moraine.

R. W. STILES & CO., PRINTERS, WAIMEA STREET, NELSON

" •*J-*Jjj\j\y

586760

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