November 30 , 1882 . ] JOURNAL OF HORTICULTURE AND COTTAGE GARDENER. 499 
beginning with the letter C. This was Centrocarpha grandi- 
flora, under which name I had received the plant from the late 
Mr. George Wheeler, who probably did more to preserve hardy 
perennials when they were not fashionable than any other man in 
England, and I said the former was now the recognised name. 
Judge of my feelings when I took up the Journal, and was in¬ 
formed by Mr. Wolley Dod that botanists would not acknowledge 
the name R. Newmani, but that the plant in question was Rud- 
beckia speciosa. Well, I hope I have the right name now, but I 
confess I am not over-sanguine about it. 
If it is unfair to blame the botanists for this confused nomen¬ 
clature, as your correspondent infers I do, it is certainly quite as 
unfair on his part to blame the nurseryman ; for as far as I recol¬ 
lect when I was living in the neighbourhood of London, the 
nomenclature at the two great botanical gardens there was not 
always identical. Where, then, are we to find the “ competent 
authorities ? ” It is comforting to learn that Professor Asa Gray 
knows Michaelmas Daisies, and that he is preparing a monograph 
of them ; but when the monograph is completed will British 
botanists accept it, or will it only result in a few additional 
synonyms ?— Wm. Taylor. 
PLANTS IN LATE VINERIES. 
How often do we, on entering a late vinery where the crop is 
hanging, find the borders bare beneath, and the fruit and fading 
leaves above to look at. This is, perhaps, accounted the right 
thing in places where there is ample accommodation for every¬ 
thing. In most gardens now gardeners are obliged to make the 
most of every available space at their disposal in the autumn no 
less than the spring. Like many more gardeners I find it rather 
inconvenient to have even a late vinery empty for some three 
months in the autumn, and really, after all, it is not necessary 
that it should be so. This autumn we have had Ferns thinly 
arranged on our late house borders set on inverted pots, and 
amongst them Gloxinias, which gives the house a furnished and 
pleasing appearance. The Ferns—chiefly Adiantum cuneatum— 
were grown under the Vines all the summer in various sized pots 
for decorative purposes and for cutting from, and for both pur¬ 
poses the atmosphere of a late vinery keeps them in good condi¬ 
tion. Gymnogrammas also thrive remarkably well. The Glox¬ 
inias were flowered last May and rested for two months, but not 
dried off, and were started in August in a Cucumber house, from 
which they were transferred to the late vinery as they came into 
bloom. The blooms are not so liable to damp in an airy house 
at this season as they are when more moisture is present; they 
require less water at the roots, they last longer in bloom. It is 
surprising that Gloxinias are not more extensively grown, for they 
are most accommodating plants. There are few plants indeed that 
can, with so much certainty and so little trouble, be had in bloom 
twice a year. No one need be afraid to have plants in his late 
vinery if he be careful to warm and ventilate them properly, and 
water carefully. The plants being placed on inverted pots the 
water passes through the latter into the border without causing 
any dampness in the atmosphere.—R. Inglis. 
DEW IN HOTHOUSES. 
Without interfering too much in the discussion between Mr. 
Taylor and “ W. Y.” I may perhaps be permitted to make a few 
remarks on this subject, being much interested in the matter from 
the same reasons that influence Mr. Taylor, who, I think, has 
acted rashly in staking the value of his treatise or the correctness 
of his ideas on the subject of dew. In the first place Mr. Taylor, 
judging from his language, has a wrong conception of what is 
meant by the “ dew point,” and this I gather from the following 
passage at page 447. Speaking of our hothouses he says, “ I he 
temperature does not decrease so rapidly as that outside owing to 
the presence of warming apparatus, &c,, which checks radiation, 
so that what is generally called the dew point is not actually 
reached.” From this it is plain that Mr. Taylor imagines the 
dew point in the glass house and outdoors must necessarily be the 
same ; and further, “ that what is generally called the dew point ” 
is some fixed point of the thermometer. So far as I can make 
out his words will bear no other construction than this, and on 
both points he is in error. The dew point under a glass roof 
and outdoors need not necessarily be the same, and there is no 
occasion for the temperature of the former to fall as low as it 
does out of doors in order that the dew point may be “actually 
reached.” For a subject of this kind it is best to start with a 
clear conception of the meaning of words and terms, and I would 
here explain what the “ dew point ” is. I quote from Wells, 
Le Roi, and Wilson, the best authorities on the subject. “For 
any assigned temperature of the atmosphere there is a certain 
quantity of aqueous vapour which it is capable of holding in 
suspension at a given pressure. Conversely, for any assigned 
quantity of aqueous vapour held in suspension in the atmosphere 
there is a minimum temperature at which it can remain so sus¬ 
pended ; this minimum is called the dew point.” 
Mr. Taylor will therefore see that the dew point varies, and 
that there is no such thing as a dew point “ generally called ” in 
the sense he puts it and as I apprehend him, hence his reasoning 
between indoor and outdoor temperatures in the passage quoted 
by me is fallacious. His hothouse may stand at 100° at some 
period of the day, at which figure much moisture will be held in 
suspension, and when the minimum point is reached at which 
that amount of moisture can be sustained the dew point will be 
reached whatever be the outdoor temperature; and hence in 
practice we often see dew formed in hothouses and elsewhere 
when there is none outdoors, as, for example, under the conditions 
named by “W. Y.,” as quoted by Mr. Taylor in his third para¬ 
graph. The rest of Mr. Taylor’s remarks are not quite clear to 
me, but if his object be to make out that “ dew formation in 
his hothouses” is due to other laws than that under which it is 
formed elsewhere, then I am afraid he has set himself a task. 
The time when dew is generally seen on Vines under glass most 
plentifully is just about sunrise, when the pipes have cooled and 
the foliage is cool also and filled with cold sap. Dew is then pro¬ 
duced by condensation on the well-known principle explained by 
“ W. Y.” Soon after, however, the foliage gets warmed to the 
temperature of the vinery, and the dew is again dissipated by 
evaporation, just in the same way as a cold dry slate taken into 
a warm house will first become wet and then dry again on the 
same principle. The dew point in a hothouse must necessarily be 
an artificial one, and the difference between the dew points in¬ 
doors and out is shown by the cold slate itself, which in the warm 
house immediately creates a dew point in the air it comes in 
contact with, causing the latter to part with its moisture, while 
outdoors that would not have happened.— Casual. 
Several favourable notices of Mr. W. Taylor’s work on the 
Vines at Longleat have appeared in continental publica¬ 
tions, especially in L'Illustration Ilorticole, the Bulletin d' Arbori¬ 
culture, and L' Opinion. It has also been decided to publish a 
translation of it in French in the “ Transactions of the Belgian 
Federation of Horticulturists.” The culture of Vines is being 
greatly extended in Belgium, and to this circumstance the interest 
in a really practical and lucid treatise is largely due. 
- The Conservatory at Messrs. E. G. Henderson and 
Sons, Pine Apple Nursery, Maida Vale, is now exceedingly 
bright and attractive, a large number of Chrysanthemums being 
very tastefully arranged around the stages, and proving the value 
of such plants when judiciously employed for decorative purposes. 
The varieties are numerous of all sections, including a good selec¬ 
tion of old and new forms. In contrast with the Palms, Ferns, 
and similar fine-foliage plants which occupy the stages, the bright 
flowers of the Chrysanthemums have a most pleasing appearance. 
- Referring to “F. H. W.’s ” question about destroying 
ants, Mr. J. Smith, The Gardens, Oakham Park, Ripley, Surrey, 
writes as follows :—“ I was at one time much troubled with 
ants in a Melon house, and was quite unable to find their nest, 
so I endeavoured to poison them. For a trial 1 took two tea¬ 
spoonfuls of best brown sugar, about a tablespoonful of water, 
and a small piece of phosphor paste, mixing the whole well to¬ 
gether and placed in a wineglass, which was inserted in the bed 
so that the top of the glass was level with the surface. The result 
was that the next morning the contents of the glass was one thick 
mass of dead ants. It is best to have a glass vessel larger at the 
bottom, as this will prevent them crawling out when once they 
