the margin of the lateral lobes colourless. Column short, thick, 
white. W. J. H. 
Cur. This fine tropical epiphyte requires to be grown in 
the warm Orchideous house, fixed to a block of wood or some 
such surface, as mentioned at t. 4427, on which its aérial roots 
may attach themselves. During its season of growth the 
atmosphere of the house must be kept warm and moist, and 
gradually lessened when the plant indicates a cessation of 
growth, which may be known by the points of the roots 
ceasing to elongate. In our Orchideous houses it becomes 
difficult to regulate the temperature and moisture so as to 
give the numerous species, of various habits, which we have 
under cultivation, their proper season of growth and repose, 
some having by nature a tendency to grow at one particular 
season, and some at another. It is the understood rule to 
consider our summer months as analogous to the “rainy” 
and growing season of the tropics, and this, by the aid of the 
artificial means at our command, we can readily imitate ; but 
the “dry” season of the tropics presents a great difficulty, for 
as it coimcides with our winter months, when the atmosphere 
is charged with moisture accompanied with a low tempera- 
ture, but which in the tropics is characterized more by a want of 
rain than any diminution of heat, and as to maintain a dry — 
tropical climate in our hot-houses in winter would require a 
greater quantity of artificial heat than would be conducive to 
the health of the plants, it is the practice to lower the tempera- 
ture and reduce the amount of moisture to the minimum degree 
necessary for counteracting the bad effects of the necessary arti- 
ficial heat. But even under such treatment, we have observed 
that the several species of Vanda, Aérides, Saccolabium, &e., are 
always inclined to grow during the winter and spring months ; 
we have also observed that in summer, immediately after 
flowering, they cease to grow, and will then bear a considerable 
degree of exposure to dry heat without bemg injured (the heat 
and dryness at this season being natural). In the autumn 
months, when the sun begins to lose power, the atmosphere of 
the house will naturally become moist, which again stimulates 
the plant into growth. From these observations we consider 
that the period of rest for these plants, in our climate, under 
artificial cultivation, is the latter part of our summer, when they 
have done flowering ; and in order to give them their natural 
requirements in that respect, it is necessary to have separate 
compartments of the Orchideous house. J. 8. 
