August ll r oo. 
THE GARDENING WORLD 
795 
Nightingale. AmoDgst rose flakes we should men¬ 
tion Pandora, Tim Bobbin, Sybil, Tbalia, and Mrs. 
Rowan, the latter a very rich colour. Scarlet flakes 
include Miss Constance Grahame, the bright Flam¬ 
beau, Guardsman, Alisemond, and various others 
so well to the front in their class that selection is a 
difficult matter. 
White Ground Picotees. — Few flowers are 
more delicately lovely than this section of the 
Carnation, having the colour of each respective 
variety confined to the margin, the rest being pure 
white. Amongst new varieties of this year Grace 
Darling is a lovely flower with a light red edge- 
The light purple edge of Lavinia is equally refined 
in its way. Minos has a broad margin of deep red, 
and is very handsome. Amongst older varieties 
Somerhill is one of the best purple edged sorts. 
Mrs. Beswick is a splendid broad, rose edged 
variety. 
PLANTS RECENTLY CERTIFICATED. 
The undermentioned awards were made by the 
Royal Horticultural Society on the 31st ult. 
Orchid Committee. 
Cattleya F. W. Wigan. —The sepals of this bold 
flower are dull, rosy-purple. The petals are twice 
as broad, oblong, and brighter rosy-purple. The lip 
has a transversely oblong, bifid, wavy purple lamina, 
with crimson-purple veins. The side lobes are 
streaked with purple. The parentage was C. 
schilleriana x C. dowiana aurea. (First-class Certi¬ 
ficate.) Sir F. Wigan, Bart, (grower, Mr. W. H. 
YouDg), Clare Lawn, East Sheen. 
Cattleya porphyrophlebia. —Here we have a 
hybrid from C. intermedia x C. superba. Although 
not new it is uncommon, and was shown in grand 
condition. The sepals and elliptic petals are of a 
soft lilac. The tube of the lip is also similarly 
coloured ; while the terminal lobe is bifid, wavy, 
fringed and closely marbled with purple on a paler 
ground. (Award of Merit.) Sir F. Wigan, Bart. 
Laeliocattleya Remula. —The parentage of this 
bigeneric hybrid was Cattleya Aclandiae (female) 
and Laelia tenebrosa, the evidence of both being 
well marked in the progeny. The sepals and petals 
are oblong-linear, bronzy-brown, and shining. The 
lamina of the lip is transversely oblong or reniform, 
and rich purple with a white edge. The lateral 
lobes are triangular, obtuse, and white as well as the 
tube, with the exception of a few purple lines along 
the base. (Award of Merit.) Messrs. J. Veitch & 
Sons, Ltd., Chelsea. 
Cyrtopera plantaginea.— This curious Orcbid 
produces a long, arching spike of flowers having 
pale green sepals, white petals, and rosy plates on 
the white lamina of the lip. (Botanical Certificate.) 
F. W. Moore, Esq., Curator of the Royal Botanic 
Gardens, Glasnevin. 
Odontoglossum cruentum. —The flowers of this 
uncommon species are about the size of those of 
Oncidium luridum, and have a similar, dusky, or 
fuscous-brown and yellow hue. (Botanical Certifi¬ 
cate.) F. W. Moore, Esq. 
Phaius bicolor —The sepals and petals of this 
old plant are bronzy.yellow. The specific name 
refers to the lip, the lower part of which is yellow, 
and the terminal lobe white, margined with delicate 
rose. (Botanical Certificate.) J T. Gabriel, Esq. 
(gardener, Mr. E. Ranson), 32, Palace Road, Streat- 
ham Hill, S.W. 
Floral Committee. 
Nymphaea marliacea rubro-punctata . — The 
sepals of this grand Water Lily are olive-brown 
externally and pinkish-white internally. The petals 
are broad, ovate-lanceolate, and densely mottled 
with rose on cream. The anthers are orange. 
(First-class Certificate ) Leopold de Rothschild, 
Esq. (gardener, Mr. J. Hudson), Gunnersbury 
House, Acton, W. 
Nymphaea sanguinea. —-The flowers in this 
instance are much smaller, but the petals are of a 
deep crimson-red. The sepals are coloured like 
those of the above. (Award of Merit.) Leopold de 
Rothschild, Esq. 
Hedychium F. W. Moore. — In this we have a 
beautiful hybrid between H. coccineum and H. 
coronarium, with buff-orange flowers deepening in 
colour at the base of the segments. The large, lip¬ 
like, petaloid stamen is transversely oblong and 
two-lobed. (First-class Certificate.) F. W. Moore, 
Esq. 
Begonia S. T. Wright.— The flowers of this 
double, tuberous variety are of huge size, clear 
salmon-orange, and very handsome. The petals are 
of great breadth, and arranged round a single 
centre. (Award of Merit.) Messrs. T. S. Ware, 
Ltd., Hale Farm Nurseries, Feltham, London. 
Begonia Mrs Andrew Tweedie —The structure 
and form of the flowers of this variety are in all 
respects similar to those of Begonia S. T. Wright, 
but the petals are white, with a creamy tint at the 
base. (Award of Merit.) Messrs. T. S. Ware, Ltd. 
decompose it. The CO, 2 of the atmosphere enters 
the leaves, unites with water (H 2 0 ), and forms the 
first visible product, namely, starch, though formic 
acid, and oxalic acid, may be formed before starch 
Experiments to prove whether roots would take in 
CO a in the way that leaves do, have resulted in 
failure. Prof. Henslow explained how an experi¬ 
ment had been made upon a large growing shoot in 
relation to its assimilation of CO,. The top part of 
the said shoot was encased in a cube, the cube being 
devoid of carbon dioxide. No starch was formed. 
The central part of the stem was sheathed by tin- 
foil, and light being thus excluded, the starch also 
THE USES OF LEAVES. 
This was the title of Prof. Henslow's concluding 
lecture at Chiswick, delivered on Wednesday, 
July nth. 
Leaves, to perform their own work individually, 
must be green. When covered over and excluded 
from light, they soon become yellowish or white, and 
are of no use in the economy of the plant. As a rule, 
green-leaved plants are more vigorous than variega¬ 
ted ones. Such plants as the Dodder (Cuscuta), 
which is parasitic upon the Hop, &c., are whitish 
but then they do not acquire their raw food like 
green plants. The diagram of a Dahlia leaf was 
shown in transverse section. Seen thus in magnified 
form the leaf structure is similar to that shown in 
the accompanying sketch. The oblong upper cells, 
marked P, contain most of the chlorophyll, and 
there little granules seize hold of sunlight as it 
streams down, utilising its various powers for the 
preparation of building and nourishing matter. 
Chlorophyll is composed of protoplasm having green 
colour-threads throughout. 
The composition of the solar spectrum is known 
to consist of seven fundamental colours, red, orange, 
yellow, green, blue, indigo, and violet. But if the 
solar spectrum be viewed against a wall for instance, 
by the aid of a telescope, a large number of black 
lines iu addition to the seven bands of colour will be 
seen. The first discovery of the lines was made 
about i860 by Herr Wilhelm Hofmann. For some 
time their meaning was not understood. A chemist, 
however, on vaporising some sodium on occasion, 
accidentally discovered that the sodium beam repre¬ 
sented line D, as marked off by Hofmann on the 
spectrum. The coincidences by vaporising substances 
of the ground and comparing them with the sun’s 
spectrum has enabled chemists to tabulate with 
certainty, the chemical elements included in the sun. 
The ordinary elements composing a ray nf solar light 
are obstructed by the beams of the various chemical 
elements which are represented by the various black 
lines, while fractions of the ordinary colour bands 
are suppressed. Nothing is ever wasted in Nature. 
Though the rays of light are not seen to have any 
violent influence upon a leaf or leaves, yet they are 
the sources of energy, for certain heat rays and 
chemical rays are included In sunlight. The heat 
rays we sometimes forcibly feel; the chemical rays 
are proved by their effect on carpets, &c. Of course 
light, heat, electricity, and mechanical force are only 
different phases of the same thing. 
Assimilation. —All animals are constantly exhal¬ 
ing carbonic acid gas, and taking in oxygen. Plants, 
chiefly by means of their leaves, take in the C 0 2 
(carbon dioxide), which is hurtful to animals, so they 
act as air purifiers. CO z is one of the most refrac¬ 
tory substances in nature, nothing except leaves can 
in this case could not form. The lower part of the 
stem having a supply of CO, 2 in the cube, yielded 5 
per cent, of starch. 
Now if white light has this effect on growth, have 
not the other rays of the spectrum also an indi¬ 
vidual effect ? Prof. Henslow showed what results 
his own experiments had. He had grown a number 
of Lettuces (all of the same weight and appearance 
to start with) under different coloured glasses. 
Ruby light caused great elongation of the stem ; 
yellow had almost the same effect; green light had 
a slight elongating power; blue yielded a short¬ 
stemmed plant; and under clear glass, of course, the 
plant developed as in the open. To prove his 
statements the professor had the various plants 
dried and mounted, and showed them to his 
audience. Immediately after lifting the plants, he 
weighed them with the following results :—Under 
red light the Lettuces were 263 times the weight 
they were when first planted ; yellow, 435 times as 
heavy; green, 157 ; blue, 294; clear light, 447 ; 
open air, 673 times their original weight. Thus the 
yellow and blue (of the coloured lights) yielded the 
maximum of assimilation. 
The dry substance weight showed, of course, less 
difference. The percentage of dry substance assimi¬ 
lated was found in Cabbage as follows:—red, light, 
11 6 ; green, 6 4; blue, 8 9 ; violet, 6 8 ; clear light, 
32 8. 
Green light is worse than useless to the plant; for 
it but falls upon the leaf and passes uneffectively 
through. Furthermore, it cuts off the red and 
orange rays the plants require. Green light is 
not wanted at all. The Palm house at Kew, 
and Mr. Thomson’s experiments in the 
vineries at Clovenfords, N.B., where green-glass 
glazing was tried, have shown that it was not in the 
least beneficial. If a shading must be used for a 
glasshouse, employ a white mixture. And the result 
of all experiments made in this direction is : " Don't 
use any coloured glass at all.” One ray of light 
is required for one purpose; another ray performs a 
slightly different function, and thus when all are 
combined as in white light, the perfection in this 
respect is accorded. 
Prof. Sachs has a half-formed theory that the blue 
end of the spectrum has the greater influence on the 
production of flowers. 
Transpiration is the process of giving off 
moisture from the leaves. A striking illustration 
showing the effect of light on the evolution of oxygen 
from a green leaf is shown by means of an aerobic 
bacterium If a piece of Alga be placed in a tube 
containing water and bacteria, it is found that 
the latter congregate thickly where the oxygen is 
most liberal If instead of white light a spectrum 
be reflected on the tube, the bacteria are found to 
aggregate at certain points corresponding to the 
