346 THE COTTAGE GARDENER AND COUNTRY GENTLEMAN’S COMPANION, September I, 1857. 
IMPLEMENTS AND OTHER CONSTRUCTIONS SUITED EOR GARDENS. 
Exhibited at the Horticultural Society’s Show at Chiswick. 
(Continued from page 314.) 
Messrs. Cottam and Hallen, ofWinsley 
Street, Oxford Street, exhibited, amongst 
other articles, this ornamental iron struc¬ 
ture filled in with wirework, and answering 
the purpose of an arbour, summer-house, 
and temple, for training Roses and other 
flowers and shrubs. It is made upon an 
improved principle, combining economy 
with simplicity and elegance of appear¬ 
ance, and so constructed as to be packed 
in a comparatively small compass, while it 
can be easily put together and fixed by 
any ordinary person, and if not required 
for a permanent erection can readily be 
taken down and laid up until again wanted 
for use. A model of the same is ex¬ 
hibited at the manufacturers’ show-rooms, 
2, Winsley Street, Oxford Street. 
THE VINE MILDEW. 
By Professor Giovanni Amici. Read 
before the Royal Academy of Florence. 
It was in October, 1851, that I first 
found a fructification nearly similar to the 
one in question on an analogous cryptogam 
on the Gourd; but, as I had then no 
means of demonstrating its origin, I did 
not venture to publish it, as there remained 
doubts in my mind whether the organs I 
then found intermingled might not belong 
to two different plants. But ulterior ob¬ 
servations have caused these doubts to dis¬ 
appear entirely, for, adopting the use of re¬ 
flected light in order to observe the objects without altering 
their natural position, I could see the stalks of the sporangia 
inserted into the same filaments of the mycelium from which 
proceeded the sterile fronds. Besides that, I often met with 
fructifications having one of the white utricles directly 
attached to their free extremity, so that the evidence of 
the passage or transformation of one organ into the others 
became perfectly clear. Sometimes, also, I met with fructifi¬ 
cations contracted in the middle, as if they were formed of 
two joined together. All these details are faithfully intro¬ 
duced in the preparation No. 2, which shows at a glance, on 
a highly magnified scale, the whole development of the 
cryptogam. 
On carefully examining with transmitted light, and with a 
magnifier of at least 600 diameters, the sporangia of our 
cryptogam, we find them to consist of a coloured cellular 
membrane, with the polygonal faces somewhat convex, and 
which includes some hundreds of spores, which, at their 
maturity, issue in jets by the mere action of water (I counted 
as many as 289 in one heap). The form of these spores, 
which are tolerably transparent, much resembles that of the 
sporidia of some Lichens. They are reniform and ovate- 
oblong, and, under a very powerful object-glass, two little 
cavities may be observed at their extremities, containing a 
most minute globule of some denser matter. The prepara¬ 
tion No. 3 represents a sporangium with its contents magni¬ 
fied to 1800 times the diameter. 
Probably the spores which I have mentioned are the 
reproductive corpuscules which Professor Pietro Savi saw 
vegetate under the microscope, believing them to have 
issued by a regular longitudinal dehiscence from the utricles 
of the moniliform filaments which had been supposed to be 
the sporangia. But this opinion, although maintained by 
other eminent botanists, is at variance with the facts shown 
by my own observations. The preparation No. 4 includes 
five of the above-named utricles, magnified to 1800 diameters. 
The first utricle is, in the ordinary state, attached to the 
apex of the ascending filament, with a portion of the corre¬ 
sponding mycelium. Two other utricles are in the process 
of germination, and vegetate and reproduce the plant after 
the manner of grafts or cuttings. The appendage which 
they emit from one extremity of the axis, which is always 
excentrical, resembles the pollen tube issuing from its grain. 
It is very easy to obtain this result. It suffices to moisten 
a bit of glass with the breath to cause a number of fresh 
utricles to attach themselves to it, disarticulating from the 
filaments. After about three hours nearly the whole of them 
will vegetate, and the germs will grow under the eye of the 
observer, till after one or two days, the nutriment supplied 
to them by the internal substance of the utricle being 
exhausted, they will die and dry up. A fourth utricle in the 
above-mentioned preparation, No. 4, shows the manner in 
which these organs usually shrivel and dry up. On losing, 
by evaporation or any other cause, the fluid by which the 
membrane was distended, it compresses on three sides. The 
extremities, being of a more compact substance, do not give 
way so much, and hence three longitudinal ribs or angles 
are formed, and the central one, by an optical illusion 
occasioned by the manner in which the light is refracted, 
may easily be mistaken for an aperture, whilst it is in fact 
nothing more than a plait or fold. The fifth utricle in the 
preparation is a representation of an artificial section in 
order to show the very variable globules, and the mucila¬ 
ginous liquor which the membrane contains. 
From the above data it clearly results that the cryptogam 
prevailing on our Grapes, which is identical in all the 
specimens I have been able to procure within a radius of 
twenty miles round Florence, is a very different plant from 
the Erysiphe communis , which no one has observed to appear 
upon the Grape-berry. I have, indeed, observed upon other 
plants the true Erysiphe with characters far too decided to 
confound it with this cryptogam of the Vine. It is a beautiful 
object when seen through the microscope with reflected light, 
when the field comprises a number of conceptacles in dif¬ 
ferent stages of maturity. Their brilliant colours, which 
pass gradually from a pale yellow to orange, to red, to dark 
