46 THE ORCHID REVIEW. [ FEBRUARY, 1903. 
or asuggestion fromsome one. As the second parent was not described till 
1893—even then its native country was unknown—it is not particularly 
remarkable that siamense should have been described as a species, especially 
as I had not then seen callosum sublzve, and never suspected its identity 
with siamense. 
It is extremely satisfactory to have the whole question cleared up in this 
way, and Mr. Young must be congratulated on his prowess. There are 
many other cases where similar experiments might be undertaken with 
great advantage to systematic botany. 
R. A. ROLFE. 
CALENDAR OF OPERATIONS FOR FEBRUARY. 
By JOHN Mackay, The Gardens, Highbury, Birmingham. 
DuRInG the month of February the temperatures given in the preceding 
Calendar should be maintained, allowing a slight rise with increasing sun 
heat. In the daytime, with sun heat, it matters little how much the rise of 
temperature may be, provided there is sufficient air and moisture to balance 
matters. At the same time avoid letting the hot-water pipes become too 
warm. Immediately on the appearance of continued sunshine means 
should be taken to prevent any excess of fire-heat, a most unnecessary evil 
at any time. In ventilating the houses great care must be exercised to 
avoid draughts, as bright sunshine is often accompanied by very cold winds. 
A sharp look-out must also be kept for insect pests, which may be kept in 
check by the application of the necessary remedies. 
RE-POTTING ORcCHIDs.—The busy time will soon be with us once 
again, and I take this opportunity of giving a few practical hints on this 
delicate operation. On the way this operation is performed depends the 
future health of a plant. Never disturb a large plant unless it absolutely 
requires it ; and the same may be said of smaller ones, only a small plant 
may be done with less risk, because it is unnecessary to disturb the roots 
so much. When repotting is decided upon, select the proper time for this 
operation, which is, with few exceptions, just when new growth or roots are 
pushing from the base of the pseudobulbs. Use perfectly clean pots, pans, 
and crocks. Fibrous peat, leaf-soil, and sphagnum moss form the principa] 
potting materials, and may be used according to calendarial directions. 
Always mix the compost well together before using, and work the material 
in carefully between the roots with the fingers of one hand, while the other 
holds the plant in position. Never cramp the roots together in one place, 
but distribute them regularly about the pot. Make the compost moderately 
firm, not too firm, nor yet too loose. It is necessary to fix some plants 
firmly in their receptacles to prevent them from toppling over, such as 
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