January 8, 1885. ] 
JOURNAL OF HORTICULTURE AND COTTAGE GARDENER. 
39 
base ! ” and, -what is worse, (he young berries are “ covered with pro¬ 
minent glandular bristles, which harden, as fruit advances, into stiff sharp 
spines, so that whatever its flavour may be, it seems perfectly inaccessible 
in the common way of eating Gooseberries.” Another species, R. Cynos- 
bati, the Dog Bramble Gooseberry, a native of Canada, has also prickly 
fruit. 
Nearly all the Ribes grown as ornamental shrubs are natives of the 
North Americen Continent; one or two, however, are found only in 
South America, and a few in Siberia, Hungary, and other parts of Europe. 
—W. T. 
MILDEW ON ROSES. 
Mr. Clayton, page 435 (last vol.), takes exception to my reply to “F,” 
pages 417 and 381, asking for the cause of mildew on Roses and Chrysan¬ 
themums, in which I briefly stated what I believe are the conditions most 
favourable to the germination and development of the spores of this 
troublesome parasite. I also ventured to recommend the best antidote I 
knew for the prevention of its ravages. Although Mr. Clayton does not 
positively contradict my statement that “ mildew is more prevalent in 
cold wet summers,” he indirectly infers that the assumption is erroneous. 
He says, “ Now I do not think anyone can call the summer of 1884 wet or 
cold, yet mildew on Rose trees has been very prevalent in this neighbour¬ 
hood (North Cheshire).” This is quite possible, but it does not in the 
least disprove my statement, because even one day, nay, even a few hours, 
of wet cold weather during spring or summer is quite sufficient in any 
locality, especially a naturally damp one, to cause the spores of mildew to 
germinate and spread to an alarming extent, and if its first appearance 
be treated with indifference or neglect, and it be allowed to fix itself 
firmly on a plant in the open air, its progress is not only difficult to arrest, 
but it is almost impossible to destroy it altogether. 
11 Mr. Clayton further questions the value of sulphur, which I recom¬ 
mended in combination with clear soot water as a preventive. He says, 
“ Sulphur is a snare, and not a preventive ; its effects are only temporary, 
and are gained at the cost of disfigurement.” Sulphur is, I admit, in the 
true sense of the word a snare or trap to catch ant destroy mildew in its 
earliest stages, but when set foi this purpose on outdoor Roses its efficacy 
is dependent on a very variable and fickle spring—fine weather. If used 
in wet weather its potency is quickly nullified, but when used in fine 
sunny weather it is very effectual as a preventive in destroying the germs 
of the disease. It is, I also admit, even in fine weather but a temporary 
remedy, and should be frequently repeated ; and in showery or damp 
weather, when, as so plainly shown by Mr. Worthington Smith, page 478, 
the spores of mildew are so numerous, they germinate so freely, and 
are wafted about so easily, it becomes even more “ temporary ” still, and 
so as to counteract the disease by destroying every fresh spore which may 
alight on the plants its application should be repeated the oftener, or as 
Mr. Smith so plainly puts it “ in the earliest stages of the growth of the 
fungus before the spawn threads are woven over the little organs of tran¬ 
spiration, and before the leaves are injured by the piercing of the little 
suckers from the fungus spawn.” It is very satisfactory to me, as I am 
sure it must be to many other rosarians, to find such an eminent authority 
as Mr. Smith attesting the value of sulphur as a preventive of mildew on 
Roses. It may be temporary in its effects, but this is but a weak argument 
against its use, seeing that nearly all garden operations are “ temporary,” 
and such are they likely to continue while time lasts. “ Disfigurement ” 
to foliage there may be from its application, but when used as I have re¬ 
commended the disfigurement is so slight as scarcely to be noticed, and 
when compared with the hideous appearance of plants affected with 
mildew is not worth consideration. It is very probable that the addition 
of a small quantity of soap, as recommended by Mr. Smith, would make 
it even more efficacious and less observable. 
Mr. Clayton further says:—“We want to get at the root of the 
matter, and not to content ourselves with guesses and nasty mixtures.” 
No doubt there is yet much to be learned in respect to the germination 
and development of parasitical fungi under the heads Rust, Smut, Mildew, 
and Mould, as arranged by Dr. Cooke in his very excellent work, “ Micro¬ 
scopic Fungi,” to which Mr. Smith alludes, and which there can be no 
doubt every gardener could read with great advantage ; and having done 
so I venture to think there are few who would even then feel that they 
had got sufficiently at the “root” of the subject to justify them in dis¬ 
continuing the use of those preventives of which Mr. Smith approves, but 
which Mr. Clayton, I think, somewhat hastily condemns. In respect to 
the conditions which are most favourable to the growth of parasitic fungi a 
few remarks made by Dr. Cooke are very significant. To find them he 
says, “ Where shall we go ?” 
“ Hedge banks, the sides of ditches, borders of woods. Our favourite 
localities have always been the dampest places in woods, railway banks, 
and waste places.” These remarks do not seem compatible with the 
theory that dry seasons are most conducive to their growth. Mr. Smith does, 
however, infer that dry weather appears to favour the growth of the Pea 
mildew (Erysiphe Martii). My experience, however, leads me to believe 
that this pest does not flourish in dry weather, unless hot dry days are 
succeeded by damp foggy cold nights, and when such conditions exist no 
amount of watering at the root will destroy it, as I have proved in many 
instances ; but if syringed freely with clear weak lime and soot water, 
with the addition of a small quantity of sulphur, its growth will be imme¬ 
diately checked. 
That the spores as well as the mycelium of Rose mildew can both be 
checked in their growth and rendered harmless, if not totally destroyed 
when the atmosphere surrounding them is under control, is perfectly 
understood by all experienced practitioners. Take, for instance, a well- 
constructed efficiently heated Rose house, situated in a moderately dry 
and sunny position. Place some pot Roses affected with mildew therein, 
and so regulate the atmosphere in respect to heat, moisture, and ventila- 
lation as to produce a temperature suitable to the growth of the Rose, 
with the atmospheric dryness as stated at page 417, and the spores and 
spawn of the mildew will be dried up in a few days; give a dusting of 
dry sulphur throughout the house, also over flues or pipes, and the destruc¬ 
tion or check to mildew is the more rapid and effective. While these or 
similar conditions are continued the plants will remain free from its 
attack, but as warm spring weather approaches, and fires are no longer 
deemed necessary, the moisture by watering and syringing is increased. 
Clear sunny weather necessitates abundant ventilation ; cold nights cause 
low temperatures; with a condensed damp atmosphere the hateful spot is 
again visible, and almost as soon as detected the whole house appears to be 
affected. Whence did this pest come ? Were the spores simply held in check 
by conditions unfavourable to their growth, or were they fresh spores wafted 
into the houses through the ventilators, and, finding favourable conditions, 
immediately germinated ? Whichever may be the case I know not, but 
it is only necessary to restore the former conditions of the atmosphere and 
the enemy is as easily vanquished as before. However microscopists and 
those engaged in agriculture and horticulture may differ in their opinions 
as to the origin and development of the various kinds of parasitical fungi, 
there can be no reasonable doubt that nearly all of them are much affected 
by certain states of the atmosphere, and however persevering and suc¬ 
cessful a gardener may be in destroying through the autumn and winter 
seasons the conceptacles or little black boxes so clearly and graphically 
described by Mr. Smith, he will not do wisely to think he has then got 
at the “root” of the matter, and that no further “temporary” precau¬ 
tion or pieventives are needed, but should be ever willing and ready to 
use them when required, not by “ guessing ” at results, but by skilful 
practice begotten by perseverance and careful thought he should feel he 
is acting consistently and with every reasonable prospect of success.—C. W. 
THE HONEY-GLANDS IN PITCHERED INSECTIVOROUS 
PLANTS. 
The four genera of pitchered insectivorous plants at present in general 
cultivation are Nepenthes, Sarracenia, Darlingtonia, and Cephalotus. 
Attention wa3 drawn to the minute structure and physiological action of 
the first three of these by Sir J. Hooker in his celebrated presidential 
address to the British Association in 1874, while the structure and 
morphology of the last was treated of by my master, Professor Dickson 
(“Journal of Botany” 1878, 1881.) Both observers pednted out an 
attractive surface studded with honey-glands, which constituted the lid 
part, a conducting surface, either of an exceedingly smooth nature 
(Nepenthes), or beset with small downward-directed hairs (Sarracenia, 
Darlingtonia, Cephalotus), and in most cases a glandular surface 
(Nepenthes, S. purpurea, and Cephalotus), the secretion from which 
directly or indirectly assisted in digestion of animal products. In 
Sarracenia and Darlingtonia there was found in addition a detentive 
surface, covered with long deflected hairs. 
A year ago Professor Dickson further drew attention to a set of 
magnificent attractive glands along the free edge of the corrugated rim 
in Nepenthes, which he named “ marginal glands.” 
My attention has recently been directed to all the genera, and I 
propose stating here the main results. A detailed account of the com¬ 
parative results obtained by examination of the different species in the 
young and adult condition will shortly be presented to the Royal Society 
of Edinburgh. 
Nepenthes. — Examining a pitcher of Veitch’s beautiful hybrid, 
N. Mastersiana, I observed on its outer surface what seemed to be the 
small openings of honey-glands. When microscopically examined they 
were found exactly to resemble those on the inner lid surface, except that 
the gland fossa was deeply hollowed out, and opened externally by a 
small orifice, while its inner surface was clothed to within a short 
distance of the orifice by the gland tissue, very much as in sphmriaceous 
fungi the cavity of the perithecium is lined by asci. But even in this 
they agreed with the lid glands noticed by Dickson in N. lmvis, and 
termed by him “ perithecioid.” Careful study of the outer lid surface 
revealed a few similar glands. On comparison of the species and hybrids 
grown in the Royal Botanic Garden, Edinburgh, a like condition was 
found to occur in all. The presence of these on the outer pitcher surface 
of N. ampullaria is interesting, since in it the lid is rudimentary, directed 
back, and destitute of glands on its inner surface. 
At Professor Dickson’s suggestion I then examined the expanded 
lamina, and was agreeably surprised to find that glands were scattered 
rather sparingly over its upper, but pretty abundantly over its under, 
surface, especially near its junction with the stem. The tendril inter¬ 
vening between the lamina and pitcher also possessed them, and in some 
cases they were of very large size. Passing to the stem it was found 
that some species had them very sparingly, others in considerable 
number, but while resembling those on the leaf externally, they were 
sunk much deeper in the tissue of the cellular layer, and strikingly 
reminded one of a simple animal gland. 
After a comparative study of the different species I was induced to 
look at the sepals, as our garden curator, Mr. Lindsay, had mentioned to 
