April 21, 1894. 
THE GARDENING WORLD. 
529 
of its presence in these coral islands is that fruits of 
the Virginian Juniper were introduced by birds from 
the continent to the island, and that in course of 
time the species has varied so greatly, owing to local 
conditions, that it is now so difterent from its 
ancestral state as to warrant being placed in a 
separate species. 
What a Daffodil can do.—Mr. E. H. Jenkins sent 
the following communication, accompanied by the 
specimen therein referred to, to the last meeting of 
the Scientific Committee Among some Daffodils 
that were flowered in the greenhouse in February, 
1893, some few pots had become mixed. When 
flowering was complete these were set aside by them¬ 
selves, and when the foliage had died away, were 
shaken out of the soil. The few mixed ones were 
put aside for discarding, and were not troubled about 
afterwards; therefore from July, 1893, fo April 5th, 
1894, these few bulbs have been in an otherwise 
empty flower-pot, and the one enclosed was cn the 
top. Without a particle of soil, fully exposed to the 
variations of weather and so forth, and without even 
producing a vestige of root, this bulb is doing its 
best to produce the flower that it contained. I have 
heard people talk of Daffodils when forced going 
blind; but I have more than once stated, what the 
enclosed bulb seems to me to fully demonstrate, that 
if a flower-bud is once formed within the bulb, it 
will come forth in some form or other, provided 
always, of course, that the bulbs are free of maggot. 
The variety enclosed is Rugilobus, which in the 
open beds were fully developed a week ago, so that 
the coming of its flower differs but little from bulbs 
planted in due season.” 
Suntara Oranges. —In a communication to the last 
meeting of the Scientific Committee, Dr. Bonavia 
wrote :—” There is at present in the London shops 
a loose-skinned orange from India, that commonly 
known there as the Suntara Orange, of which there 
are many varieties. The Suntara Orange is the 
Citrus aurantium sinense of Rumphius, while the 
Valencia Orange or Portugal Orange, of which also 
there are many varieties, is the Citrus aurantium 
sinense of Gallesio. The Mandarin or Tangerine 
Orange is a sub-section of the Suntara type, and is a 
different thing from the latter. In a Piccadilly shop 
the Suntara Orange has been rightly ticketed as an 
Indian Orange ; but in a Bond Street shop they 
ticketed it as Mandarin Orange from South Australia. 
This is manifestly erroneous. The Australian sea¬ 
sons are just the opposite of our seasons. Their 
spring is in September, and their Oranges do not 
ripen till July. .So that these Suntara could not 
have come from Australia. The Suntara Oranges in 
Ceylon are called Mandarins by the English. 
Oranges may be thus classed :—I. Cling-skins, 
including Michaels, Blood Orange, Jaffa Orange, 
Navel Orange, Florida Orange, and many others. 
II. Free-skins, Citrus aurantium sinense of Rum¬ 
phius, Suntara Orange of India, of which there are 
numerous varieties. The Mandarin (Citrus nobilis 
of Lonreiro (?) I consider a sub-section of the 
Suntara type, but as different from it as any two 
distinct varieties of Apple or Pear. 
Edinburgh Botanical Society.—At the last monthly 
meeting of this Society, Dr. William Craig pre¬ 
siding, Mr. T. Cuthbert Day contributed a paper on 
“ The Influence of Light on the Respiration of 
Germinating Barley and Wheat.” The experiments 
which had been carried out showed that light had 
probably a small stimulating action in the germina¬ 
ting of Barley. As regarded Wheat, the results of 
the experiments were that, in respect to white 
Wheat, light was in favour, while the same condi¬ 
tions in regard to red Wheat were supported by 
obscurity. Mr. Lindsay, curator of the Botanical 
Gardens, submitted his report, which stated that 
during the month of March the thermometer was 
at or below the freezing-point on nineteen mornings, 
indicating collectively for the month 63° of frost, as 
against 64° for the corresponding month last year. 
Rain fell on eight days, and snow on four days, 
during the first half of the month. There was a 
fair amount of bright sunshine, and on the whole 
the month was a most favourable one. Vegetation 
generally had made good progress. The leaf buds 
of deciduous trees and shrubs were well advanced. 
Of the forty spring-flowering plants whose dates of 
flowering were annually recorded, eighteen came 
into flower during March. On the Rock Garden, 
seventy-five species and varieties came into flower 
during the month, as against eighty-one in the 
corresponding month last year. 
ROOT ACTION IN WINTER. 
I HAVE been watching the discussion upon this sub¬ 
ject, and although I acknowledge with the writers 
that the subject is difficult and has not at all been 
fully investigated, yet I cannot agree with “A.D.,” 
p. 469, that little more can be said in the matter. 
Even the observations that have been given 
have not been satisfactorily explained. For 
instance, such a careful observer as Mr. H. C. 
Princep, p. 454, says that the sap is suddenly driven 
out of the branches in autumn, and that it does not 
at once become consolidated, but may be a work of 
two or three weeks, or even more. The sap is also 
said to be forced to the roots till it is transformed 
into more solid matter. It is my opinion that the 
branches retain their share of sap all through the 
winter just as much as the trunk and roots do. 
It may be as well, first of all, to come to an under¬ 
standing of what is meant by' the word sap. From 
the use that has been made of it one would come to 
the conclusion that it might be anything. As it is 
taken up from the roots it is simply water containing 
the elements of plant food in a state of solution and 
that, too, in a very diluted condition. It is, in fact, 
simply the vehicle by which plant food is carried 
into the plant, and also the means of conveying 
and distributing the same over the body of the tree 
when the simpler ingredients of plant food have 
been built up into more complex substances in the 
leaves and under the action of sunlight. A small 
portion of the water taken up by the roots is 
necessary for the building up of plant food, as the 
elements of water are broken up and become 
chemically united with other ingredients to form 
protoplasm, starch, cellulose, and lignin. The 
three latter may be termed solid for the sake of 
argument ; but the sap as a whole never becomes 
solid—indeed, only a very small percentage of it. 
The superfluous moisture is given oft by the leaves 
while still on the tree, not by the roots. Mr. 
Princep speaks as if the sap was forced to the roots 
to become transformed into more solid matter. This 
cannot be the case, as sap or water cannot become 
solid except it is frozen or subjected to enormous 
pressure that does not exist in the vegetable world. 
As to the storing up of sap in deciduous trees, 
surely the writer meant something more than the 
mere storing of water. There must be something 
in the water to supply the necessary building 
material when growth is being produced in spring. 
We all know the expression that blood is thicker 
than water, and that the latter cannot supply the 
place of the former in an animal. Neither can 
young wood be built up of water. The principal 
ingredients that are stored up in plants are starch, 
sugar, oils, and vegetable fats. In our common 
fruit trees, starch is the most important and most 
abundant substance stored up. This may be 
termed solid ; but it is again rendered soluble in 
spring before it can be conveyed by the sap or 
water to the places where growth is going on, or to 
the places of activity where preparation is being 
made for fresh growth. All this may seem 
technicalities, but I fail to see how we can understand 
one another without adopting terms that alone can 
limit, define and make the subject clear. It must 
be evident that sap, if it is simply water, cannot be 
nutritious, nor go to build up the solid substance of 
a tree. Possibly Mr. Princep might make it more 
clear as to what he intended by the term. 
I quite agree with the writer in question that the 
bark of Oaks or other deciduous trees contains 
more substance just before the trees expand their 
leaves, than afterwards. This would refer to the 
stored or reserved material, starch and watery sap. 
All deciduous trees are gorged with water at this 
period, as we have evidence in the bleeding of Vines, 
Birches and other subjects, when cut at that time. 
Assuming with most of the writers that roots are 
more or less active all the winter, they become much 
more active in spring. Even if they are not grow¬ 
ing nor extending their system, they are pumping 
the water, so to speak, under pressure into the 
interior of the plant. The leaves, which are the 
natural organs forgiving off the superfluous moisture 
not being present, all the cells of the wood get 
gorged with moisture, and, root pressure still con¬ 
tinuing, the water begins to filter into the vessels of 
the wood, and which were previously filled with air 
only. When the trees are furnished with leaves, 
this could not take place, for while the superfluous 
moisture is being giveti off into the air by transpira¬ 
tion, no water gets into the vessels of the wood at all. 
This is the case during the day, in summer, or from 
the period that the trees are fairly into leaf. During 
the night when transpiration ceases, water filters 
into the vessels again in many, if not most of the 
plants, in a rapidly growing state, and we have 
evidence of it in the drops of water that ooze out at 
the-water pores situated at the edges and tips of the 
leaves. These pores are in direct connection with 
the vessels. While the wood, including both the 
fibres and vessels, gets gorged with water in this 
way, all the living tissues in other parts of the tree, 
including those of the bark, get into the same water 
laden condition ; hence the greater thickness of the 
bark. The water or sap, is not congealed, if by 
that term we are to understand that it is frozen, and 
which is the most common meaning it bears when 
applied to water, if not the only meaning. 
All this goes to show that the roots are, and must 
be, very active in absorbing moisture or water long 
before any growth takes place, and, indeed, 
before it can take place. The pumping up of water 
under pressure by the roots is a most important 
function, for so long as the cells are not turgid or 
distended with water, no growth or extension can 
take place. The buds are actually pushed into 
growth by the pressure of the watery sap, and when 
the young cells of the buds have attained a certain 
but limited length or size, they divide into two, and 
commence growing in size again by the force of the 
sap. The latter is, therefore, the active agent in 
growth ; and if it was not kept in a state of pressure 
neither buds nor leaves would move. It is not 
necessary that the roots themselves should extend 
or grow, in order to be active in absorbing moisture, 
but it is probable that in most cases they begin to 
grow at the same time as the buds, if not before. 
In the case of Orchids, young roots are formed 
before the buds push very far. Bearing all these 
facts in mind, it would be rash to state that roots are 
inactive till growth has proceeded so far, or has 
even been completed, for without their action the 
growth of either buds or leaves would be im¬ 
possible.— F. 
- ^ - 
ABOUT IRISES. 
These, in their numerous species and varieties, form 
a group of plants which, in the hardy flower garden, 
hold a similar position to Orchids among stove and 
greenhouse plants ; indeed, they have with much 
justice been styled the Orchids of the flower garden, 
and like them present marvellous variations in form 
and colour, yet with fevV exceptions are perfectly 
hardy. Those who have sufficient accommodation 
can have Irises from early winter till July ; but most 
growers will find ample material to meet their 
requirements in a collection mainly made up of the 
English and Spanish types, which are bulbous, and 
the German and Japanese flag Irises, which are 
rhizomatous. Iris reticulata and I. Susiana, among 
hardy species, also merit attention, and Iris Japonica 
(Chinensis) and Iris, or rather Moraea, Pavonia 
among greenhouse species have for a long period 
been special favourites with us. 
The German flag Iris is one of those things which 
will thrive almost anywhere, either in town or 
country, and the old purple variety is an universal 
favourite with country people, while among newer 
varieties there is an almost endless variation of 
colour. These flower mostly during the month of 
May. The Spanish and English Irises prefer a 
light or medium soil, and when convenient they are 
both best planted early in September, better flowers 
being produced than from later plantings. Iris 
Kempferi, the Japanese flag Iris, sometimes and not 
inaptly termed the Clematis Iris, is a gorgeous and 
beautiful class, requiring a rich deep soil, preferably 
a marshy situation, for they must, during the grow¬ 
ing period, have copious supplies of water. 
All Irises are well adapted for use as cut flowers, 
and many among them are very effective, inviting 
the attention and commanding the admiration of 
all lovers of the beautiful among flowers. One 
great advantage there is in their use is that if 
required to be sent long distances they may be 
gathered as the buds are showing colour and just 
before expanding, for they will then open freely in 
water, and they both travel better and many more 
can be forwarded in the same space than if fully 
expanded before gathering,— W. B. G. 
