ON THE INFLUENCE OF CLIMATE ON PLANTS. 
133 
remove them into a house where light was liberally afforded, and since then we 
have had the gratification of seeing them thrive most luxuriantly, and flower in a 
high state of perfection. 
From the accounts of travellers, we learn that many species of Cactce produce 
a great abundance of fruit in their wild and native state ; this, we presume, is 
entirely attributable to the intensity of solar light with which they are naturally 
supplied ; but that the plants which are cultivated in British collections produce 
little or no fruit, is a fact of which every individual who is at all acquainted with 
them must be aware. We do not say that Cactae are cultivated, or are worth 
cultivating in this country, solely for their fruit, but we would remind our readers 
that the means which produce fruit, will previously develop the finest flowers, and 
that these plants are cultivated not only for the singularity of their appearance, but 
also for the striking beauty of their flowers. To obtain then a great abundance of 
flowers, of rich and splendid colours, no mode of treatment, however plausible and 
suitable in other respects, can be made to supply a deficiency in solar light, and 
we consider this fact to be the prominent and most important feature in the culti- 
vation of Cact(B. 
In the collection of a private gentleman in the vicinity of London, we witnessed, 
a few months since, some large specimens of Opuntia vulgaris, which had for 
several years been planted in an open border, and trained to the front wall of a 
greenhouse ; in this situation they produce annually an almost innumerable 
quantity of blossoms, and these are succeeded by an equally profuse supply of fruit* 
Now it is well known that this species, when treated as a stove plant, certainly 
attains to a great size, but seldom if ever, develops its flowers ; so that this 
deficiency cannot be attributed to a lack of heat, nor can it be said to be caused by 
an excessive degree of it, for its native country, where its fruit forms a staple article 
of food, is situated in the tropical parts of America. Therefore, we can only 
account for the above unusual instance of this plant flowering in such profusion by 
the circumstance of its being freely exposed to the influence of solar light ; and from 
this, as well as numerous other similar cases which have fallen beneath our notice, 
we are convinced that the prevailing error in the cultivation of these plants, is not 
allowing them a sufficient quantity of the important element now under considera- 
tion, the consequence of which is, that they generally flower indifferently, and 
frequently not at all. In a few isolated instances this remark may not perhaps 
appear to apply, as some gardeners certainly cultivate these plants to an extraor- 
dinary degree of perfection ; but this excellence is only attained with a few species, 
and even with these, is solely attributable to the plants being periodically exposed 
to the sun's influences, and not, as is generally supposed, to the variation of 
temperature. We would therefore suggest, as a practical inference from these 
facts, that these plants be kept in a house where they can constantly receive the 
unobscured and unmitigated influences of the sun — that they be placed on a stage 
as near as possible to the glass — and that nothing be suffered to obstruct or 
counteract the direct and immediate rays of solar light. These remarks refer to 
