THE ORCHID REVIEW. 57 
connected with the habits of the insects which fertilise them, opening when 
they are on the wing, and closing at other times, as a protection against 
marauders. If this is the case, it would appear that some are fertilised by 
day-flying, and others by night-flying insects, and that the colour of the 
flowers is connected with their time of opening. The object of this note is 
to draw attention to the question, for several species are in cultivation, and 
observations on their time of opening and closing, together with the con- 
ditions of the light, temperature, and moisture of the atmosphere would be 
extremely interesting. Though not showy, the flowers of this large and 
widely diffused Tropical American genus are certainly very highly specialised, 
and one would like to know more about their economy. 
: R. A. ROLFE. 
CALENDAR OF OPERATIONS FOR FEBRUARY. 
By H. A. BURBERRY, Highbury, Moor Green, Birmingham. 
ALLow the temperatures for this month to remain as advised for last, with 
the exception of a few degrees rise by sun-heat as it gains in power. 
Between solar heat and that from the hot-water pipes there is indeed a 
great difference, and those growers who are so placed as to get the greatest 
amount of the former during the dull winter months should undoubtedly 
pass through the trying ordeal with the least number of plants debilitated 
or prostrate. I notice a good many of our Mexican Orchids, and others 
that are known to grow naturally in great light, are this year suffering to 
some extent bya greater loss of foliage. The cause of this I, rightly or 
wrongly, attribute to the fact that owing to the comparatively sunless 
summer of last year the leaves become somewhat sappy or unripened, and 
thus rendered unable to successfully withstand the—so far as smoky, sul- 
phurous fogs are concerned—exceptional winter. I notice, likewise, the 
greater power of those plants which have recently been imported — say 
within the last three or four years—to resist these evil influences of large 
cities on plant life, and this I take as supporting the above theory. And, 
further, is it not the same thing, with a difference, when we read of an 
Orchid growing luxuriantly under what is generally considered to be the 
wrong treatment? Our attention is sometimes called to cases of this 
description, as, for example, a hot Orchid growing well in a cool house, or 
vice versa. But are we quite satisfied that such treatment will be perma- 
nently good, or do we not rush into print a little too hastily and incur the 
chances of innocently misleading our readers? The latter, in my opinion, 
is frequently done. I admit, as before stated, that pure air and clear skies 
have a powerful influence upon many Orchids, but we must not forget that 
the aspect and general conditions of one cool house may be quite different 
