734 
THE TPwOPICAL 
AGRICULTURIST. [May 1, 1900. 
the Flora of British India. And it is in the Kew 
Herbarium that are to be found the types of an 
overwhelming proportion of the new species des- 
cribed for the first time in that monumental work. 
The Kew Herbarium is tlierefore to the Indian 
Botanist the most important that exists. I mutt 
apologise for diverging for a moment to remind you 
what a type specimen is. It is the very one on 
which an author has founded any species to whicli 
he has given a nam.e. And in order to determine 
absolutely what is the specilic form to which the 
author meant his name to apply, it is often neces- 
sary to examine his type. The necessity increases 
in urgency with the extension of our knowledge of 
the Flora of the world. 
{To he concluded.) 
THE CAUSE OF DECAY IN PLANTS, AND 
.) THE REMEDY TO GIVE TO THEM 
NEW LIFE. 
BY R* R. HARDING, CURATOR, BOTANIC GABDENS, 
TOOWOOiVIBA, QUEENSLAND. 
■ The primary object of this paper is to direct at- 
tention to the results of unskilful planting of trees. I 
will endeavour to show that this is very ex- 
pensive, and unsatisfactory in the enu. When we con- 
sider that it takes only a little time longer to plant 
trees properly, the only exuse that can be given for 
not doing so is that the persons who plant trees 
or shrubs are afraid to separate the roots for fear 
of killing the plant. It would be, as a matter of fact 
much better to kill it then than to be disappointed 
in after years. Such oases are numerous in this town 
and I am often asked by residents here and by others 
in different parts of the colony, what is the reason 
for their trees looking so miserable ? 
Before lsivea practical illustration of this, I will 
go back to the heading of this paper : " The Cause of 
Decay in Plants. " Decay or disease is the antithesis 
of health, and, as the health of the plant means the 
correct performance of its functions, disease may be 
defined to be an incorrect performance of those func- 
tions. I believe that of all the various kinds and 
forms of disease to which plants are liable, none are 
so general or so fatal as those affecting the roots. In 
many, perhaps in most cases, it is extremely difficult 
to say precisely where disease orginates and how it is 
produced. It is only when we see it in some of its 
intense forms of developemeut that wo are aware 
of its existence. • . t .r. 
On the authority of tlie wisest of men there is 
nothing new under the sun, yet there are constantly 
presented to us things that appear, and are to us es- 
sentially new. Take the position of a tree. Its position 
may he said to be unchangeable ; the soil, subsoils, 
atmosphere, and climate may be so far unvarying as 
to be also unchangeable. On the other hand, the roots 
of the tree are constantly year by year altering their 
Dositiou, traversing as it were the whole surrounding 
area in quest of food. Moisture also performs a very 
important part in the nourishment of the tree and all 
strata of soil penetrated by the roots are not equally 
full of moisture, so that when the roots pass through 
one stratum the tree is well nourished, and on passing 
through another it is less liberally supplied. Atmos- 
pheric influences also materially affect the tree, and as 
these vary so the growth varies. Insects, too, do occa- 
sional injury to trees by eating or poisoning their 
foliage, hence, as the foliage is good or healthy, or 
the reverse, ao ia the growth of the tree good or 
bad for that or for succeeding years. The mellow, 
withered, or fallen leaf in early or midsummer is not 
always a' sure indication of a diseased tree, indeed 
it is always more satisfactory to find an evergreen tree 
of any kind shed its leaves freely on agitating the tree 
than that they should tenaciously hold by the tree after 
thev have become withered. The decay or the dying 
of leaves in some instances, evidently depends on a 
want of vigour or on partial rot ia the roots, but in 
a great majoiity of cases ii is produced by iojacli, 
cious planting and after cultivation. As an instance 
of this, I may state that last September I was re- 
quested to inspect the avenue of camphors growing 
in the Royal Agricultural Show Grounds. For the 
past two or three years thsy had looked very sick, 
each year getting worse, and they would eventually 
die if something extraordinary were not soon done 
to them. Various causes have been assigned for the 
appearance of these trees by those who have expressed 
their views upon the subject, but there was no differ- 
ence of opinion as to their highly unsatinfactory 
state. Like most other places of similar extent in this 
part of the Downs, it is evident that the laud in the 
area is not all alike in its suitability for the growth 
of trees; yet allowing for the diflference, those con- 
versant with tree culture will not have long to seek 
for the cause of this decay, which has been slowly 
but surely going on. The decline is not the result 
of old age, nor of the capabitity of the soil to grow 
and maintain the trees in a healthy condition, for a 
closer inspection of similar trees growing only a few 
yards away, confirmed my first oninion, which was 
that want of timely thinning and the want of nourish- 
ment at the roots, caused by bad planting, were 
at the bottom of it all. The questions put to me 
were— " Conld anything be done to the trees to give 
them new life? Was ic advisable to plant young trees 
between them, and when these had made a start to 
then take the sick ones out ? The answer I gave was 
— " Leave them to me, with power to act, and they 
will be given new life." I remarked at the time these 
were planted that they would never make 
anything else but shrubs, and that only for 
a time. I examined the roots and foliage 
thoroughly, and found that three parts of the branches 
were dead or decaying and the foliage scant and yellow- 
tinted ; but on examining the roots I saw at once 
the cause of all the evil. The trees in the first in- 
stance, had been planted too high ; the roots when 
young had not been spread out ; they were simply grow- 
ing as if they remained in a pot, and those who know the 
size of these camphors will be surprised at my saying 
that the roots had not extended more than 6 feet from 
the stem of the tree, when they should have spread 12 
feet at the least. The roots showed up out of the 
ground 2 feet from the trunk. They had embraced 
and interlocked each other and on account of the scant 
foliage, were exposed to the full rays of the sun, 
and the remark I made at the time of planting was 
now justified. JVly firsi work was to cut out the 
dead yellow branches, the centre of which was fonnd 
to be decayed. Then all the inside branches were 
taken out, the surface of the soil under each tree 
was forked over very shallow, and outside the spread 
of the foliage a trench was dug all around the tree. 
Now this, of course, is-the proper place to apply the 
nourishment, at the mouth of any tree, as here are 
situated the extremities of the roots, and as these 
feeding roots spread out beneath the soil pretty nearly 
to the same extent as the branches above ground, 
the tree should be fed at the distance of the extremity 
of the branches above ground from the stem. Here 
Nature teaches us a lesson : The head of the tree is 
in the form of a dome like an umbrella ; all aronnd 
the soil is exposed to the rain, and the water pene- 
trates the earth just where the extremities of the roots 
are situated to receive it. In addition to this, the 
greater part of the rain which has washed and re- 
freshed the leaves trickles down from the ends of the 
branches, and reaches the ground in the appropriate 
spot. In trenching around the trees immediately 
where the branches extended, the men were surprised 
to find no roots. This was nothing more than my 
practical experience expected, because, if there had 
been roots there would have been no necessity to 
do anything to the trees ; but here was the mischief. 
The trees were then thoroughly mulched with half- 
rotten straw and manure, well covering up the large 
crinkled roots near the stem with a good coating of it. 
At the extremities, where the feeding roots should 
have been in the trench, the richest manure Wfta 
