APRIL, 1903-] THE ORCHID REVIEW. 107 
lovely genera in the whole family of Orchidacee, though this may not be 
for long, as I was recently talking to the head of one of our most celebrated 
northern firms, who makes hybridising a speciality, and he told me they 
were seriously considering the feasability of raising warmer types of 
Odontoglossum for the American climate, by crossing the cooler kinds 
with others which would stand more heat. 
Mr. Roehrs devotes about twenty-five large houses to Orchids alone, and 
it is just about twenty-five years since he began to grow them, but though 
passionately fond of Orchids he does not confine himself to this class of 
plant, for he does a very large business in palms, ferns, and general nursery 
stuff, housed in about seventy-five fine houses, and grounds covering several 
acres. The Nurseries are well within half an hour from New York, by 
23rd Street or Chambers Street ferries to Rutherford Station, and thence 
by trolly a short distance to the gates. 
It may be added that Mr. Roehrs buys all his Orchids on this side of 
the water, it being cheaper and more expeditious than importing them 
direct from South America, and I believe that he often places an order 
for several thousand imported plants in this country. 
CRASSINODE. 
CALENDAR OF OPERATIONS FOR APRIL. 
By JOHN MAckKay, The Gardens, Highbury, Birmingham. 
THE temperatures of the warmer houses should still be slightly increased, 
and air admitted more freely, yet with due caution; always taking into 
consideration the directionand force of the wind. It is of great importance 
to those having the management of a collection, to see not only that each 
division is properly ventilated, but also that no great fluctuations of 
temperature occur. During this month great vigilance will be required on 
the part of the cultivator, as with the numerous sudden changes in the 
outside temperature, it is difficult to keep up a regular temperature in the 
houses, either by day or night. The top ventilators will be needed very 
little yet awhile, and when they are used should be closed early, which they 
all may be, say about half-past two, and the houses damped down, opening 
the bottom ventilators again before leaving off for the day. It is advisable, 
for several hours during the middle of the day, to allow each division to 
become comparatively dry. This will allow the plants to throw off any 
excess of moisture, which, if retained, would probably cause decay. The 
Cool houses should be damped early in the afternoon, and again before 
leaving off if necessary, but the ventilators should always remain open, 
more or less, according to the prevailing conditions outside. 
