July 28, 1881. ] 
JOURNAL OF HORTICULTURE AND COTTAGE GARDENER. 
83 
(Renanthera) Lowii, which stands about 6 feet high, is now in 
flower at the Victoria and Paradise Nurseries, Upper Holloway. 
It has six long flower spikes, one at the present time exceeding 
7 feet in length, and has about 194 flowers and buds. This plant 
will be in flower for several weeks, and should be seen by every 
Orchid-grower. 
- A correspondent of the American Gardener’s Monthly 
has the following note upon A3SCULUS CALIFORNICA “ No one 
travelling along the foothills of our mountain ranges in spring 
will fail to remark the bright green colour of our common Cali¬ 
fornia Buckeye, nor to note the light rose tint of its blossoms. 
One of the first to bud and leaf, it is also one of the first to catch 
the eye at the opening of spring. It is somewhat remarkable 
that the A3, caiifornica is not more extensively cultivated as an 
ornamental tree (or perhaps I should say shrub) in our landscape 
collections. True it supports its bright green colour but a short 
time, but its beauty for this short period, when most other de¬ 
ciduous trees are so bare, will surely compensate one for the 
labour expended on its planting and culture. It is propagated 
from the seed, and flourishes best in a gravelly soil, such as is 
found in the foothills of the Sierra Nevada and Coast Range 
mountains. The nut, though considered poisonous in its crude 
form to both man and beast, is largely used by the Californian 
diggers as food.” 
- The same periodical gives these remarks upon hybridis¬ 
ing- Pitcher Plants: —“The finest set of hybrid Nepenthes I 
ever saw was at Such’s Nurseries, South Amboy, N.J., and some 
of these same hybrids are named, figured, described, and sent out 
by English nurserymen ; but in no case have I seen the credit 
given to the raiser—namely, Mr. James Taplin, of Maywood, N.J., 
and who was for years manager of Mr. Such’s place. Certainly 
Mr. Taplin is an Englishman, and one of the best practical 
gardeners who ever came to America, but the work he does in 
America we will claim as American.” 
- We are desired to announce that the fifth annual Exhibi¬ 
tion of the St. Giles’s Camberwell Amateur Floral Society 
will be held at Camden House, Peckham Road, on the 8th, 9th, and 
10th of August. 
WHAT PLANTS USE. 
C Continued from j>age 30.) 
Water. —Water is always present in the atmosphere. Air at 
a temperature of 32° is saturated with a 160th part of its bulk of 
water. Saturation is the point at which, were more water added, 
it could not be held in solution, but would appear as mist, fog, or 
dew. The same phenomenon occurs if the temperature be suddenly 
lowered ; it is then incapable of holding it in solution and the 
water is precipitated. It is found that the capacity of the air for 
water is doubled by every rise in the temperature of 27° —that is 
to say that air, which at 32° is saturated with a 160th part of 
water, if raised to 59°, instead of being moist it will be dry and 
capable of containing an eightieth of its own weight. Again, if 
air at 59° containing an eightieth part of water be raised to 86°, 
it will be very dry and capable of containing a fortieth part. 
Moisture in the atmosphere is very necessary to plant life, and 
when it is absent vegetation is impossible. General readers are all 
acquainted with the deadly nature of the simoom, and its destruc¬ 
tive nature is in great part owing to the fact that it is singularly 
deficient in moisture. With a capacity for a thirtieth part of its 
own weight of water, it frequently contains no more than a 
fifteenth of that amount. 
When air is too dry it absorbs the moisture from plants with 
greater rapidity than it can be replaced by the roots and flaccidity 
ensues, than which no more weakening influence can be brought 
to bear on plants. Out of doors well-rooted plants, which grow 
in soil fairly moist, seldom fail by over-evaporation. The fact is, 
even in dry weather the air seldom contains less than two-thirds 
of the maximum amount which it is capable of containing, and it 
is often saturated. Unless the air is completely saturated evapo¬ 
ration always takes place from plants ; for this reason it is not a 
good plan to put out even well-rooted plants in dry weather. 
The time to do it is when the air is near saturation point, for 
then the plants will strike root readily. Cuttings make roots 
quicker when covered by bellglasses or close case for the same 
reason ; indeed, many kinds of plants fail to root unless the 
tops are continually surrounded by an atmosphere containing the 
maximum amount of water of which it is capable of holding. 
Such tender plants as Melons and Cucumber plants and forced 
Vines are in winter, frequently suffer in early spring from the 
extreme dryness of the air. It happens very frequently that, 
with the air below freezing point in temperature, a clear sun 
shines and raises up the temperature of such houses considerably. 
Shading we all instinctively avoid if we can, for we all know it is 
an evil which results in tender growths, which cannot bear hot 
sun or dry air, nor yet produce the best results in the production 
of fruit or flowers. Ventilating is dangerous because of its admit¬ 
ting air destructive in its coldness and aridity. Scorching we 
cannot risk, and we are often in doubt what should be done. 
Often we forget what is wanted to prevent the excessive evapo¬ 
ration which causes flaccidity. Air with often less than a three- 
hundredth part of water, when admitted, even in small quantities, 
to a structure where the temperature is between 80° and 90°, soon 
approaches in its character the simoom. It is not enough to add 
heat; it is not even enough to add the necessary carbon—exhaus¬ 
tion, swift and sure, will follow unless a due amount of water be 
also added. No structure is fit for forcing purposes unless proper 
provision is made for the admission of air warmed and moistened. 
Different subjects require different degrees of moisture in the 
air. The saturation which is necessary for the Pitcher-plants and 
Orchids from the steamy shady groves of the tropics would 
prove ruinous if applied to the Vine, which thrives in the clear 
sunshine and arid air of inland Spain and Italy. Generally 
speaking the nearer saturation point the atmosphere of an Orchid 
or Nepenthes house is, at least when the plants are making their 
growth, the better. If the air of a vinery contain about two- 
thirds of the water it is capable of holding it is too moist—warty 
excrescences will follow, the elaboration of sap be sluggish, and 
the general results unsatisfactory. When the leaves of Vines are 
young and tender and the sun is powerful a little more ought to 
be allowed, but in the case of Vines after the leaves have gained 
substance much less will suffice—indeed will be preferable, for 
then with plenty of air, heat, and light, growth in its true sense 
will go rapidly on. We do not mean that the air should never 
contain more than that, for we think that nightly dewings are 
of great benefit. 
This leads to a few words on dew. In tropical regions, whence 
most of our hothouse plants come, and even in the warmer parts of 
the temperate regions where Vines, and Peaches, and other plants 
grown under glass at home thrive outside, the days are hot, clear, 
and dry ; the nights cool and moist. We do our best oftentimes 
to reverse this in our vineries. We “damp down” and “sprinkle” 
even when days are dull and the temperature low. Moisture in 
the air is necessary, but too much is hurtful, and often we keep 
the air moist during daylight to a hurtful extent. Nature teaches 
us the opposite. By night we, in too many instances, keep up a 
high and a dry temperature. Nature teaches us the opposite. In 
our remarks on air, &c., we tried to show how high night tempe¬ 
ratures undo the previous day’s work. Not only so, but high 
night temperatures cause exhaustion as well, and even by day¬ 
light they fail to go forward as under more natural treatment 
they would. After a hot day Vines and other plants need rest 
and refreshment. Why deny them ? Under even tropical skies the 
nights are cool, and plants are bathed copiously by an abundant 
dew. Under this bathing flagged plants recover their freshness 
and prepare for another day. This we should imitate. 
It is easily done. If after a hot dry day we sprinkle water 
over a vinery floor and open all the ventilators the Vines will be 
dripping with dew by morning. The reason is this : The air in 
the vinery at the close of a hot day is warm and its capacity for 
water great. When water is sprinkled about the air takes up 
much of it and retains it. When the cool night air is admitted 
by the ventilators the air inside is cooled and its capacity for 
water reduced ; it becomes saturated and ready to deposit its 
water. Moreover, the air cools the Vine leaves more rapidly than 
the stages, borders, walls, or paths, and therefore the moisture¬ 
laden air coming in contact with the cool leaves deposits part of 
its load and the Vines become covered. Should there be any 
heat in the pipes this will not occur, however, for then the 
capacity of the air for water will be maintained, and the moisture 
will be passed out by the ventilators instead of being deposited 
on the leaves. Even with closed ventilators the dew will be 
deposited, always provided the sky is clear and the outside air 
cool. A damping of the back wall in the case of lean-to vineries 
will help the deposition of dew greatly, for the wall will retain 
its heat after the Vines have lost theirs ; hence the air will gain 
