JANUARY, 1923.] THE ORCHID REVIEW. 1} 
damage the flower buds as soon as the latter commence to develope; place 
traps of damp bran or lettuce leaves about the house near to the plants, and 
search for the pests at night and early mornings. Recently imported plants 
of Dendrobiums should be laid for a few days on a stage in a house having 
an intermediate temperature. They should be carefully examined with a 
view to the removal of decayed portions, and afterwards washed with an 
approved insecticide. When they are dry again, they should be placed into 
pots just large enough to accommodate the roots, and each plant be tied 
firmly to a stick. In potting, half fill the receptacles with crocks, and the 
remaining space up to the base of the plants with a compost of equal parts 
sphagnum moss and finely chopped Osmunda fibre. Grow the plants in an 
intermediate temperature until about the middle of March, when they may. 
receive additional warmth. 
RO 
NONSYMBIOTIC GERMINATION OF ORCHID SEEDS. 
EFERENCE was madein our May issue, p. 135, to Mr. Lewis: 
Knudson’s method of germinating Orchid seed without the aid of 
fungus. The Garden Magazine, U.S.A., in its issue for November, contains 
an article by Mr. Knudson on raising seedlings on sugar, accompanied by 
reproduced photographs of tubes and flasks containing seedlings. He 
remarks that the undeveloped state of the embryo, together with the lack of 
food in storage, is undoubtedly partly responsible for the difficulty and 
uncertainty encountered in germinating Orchid seed. This suggested that 
germination should proceed if the embryo were artificially supplied with’! 
food, which is the underlying principle of the method envolved. The 
problem was to supply the Orchid embryo with sugar, which is made by 
plants, and constitutes one of their important foods. In order that the 
sugar might not be decomposed by micro-organisms, and products formed 
which might kill the embryo, the seedlings were grown under aseptic 
conditions in tubes and flasks. They were, in fact “ bottle-fed” in their 
infancy. 
Mr. Knudson uses a nutrient medium composed of :— 
Grams. Grams, 
Calcium nitrate ee ... 1.00 Ammonium sulphate aa OO 
Dibasic potassium phosphate 0.25 Agar ... ve cy we 15.00 
Magnesium sulphate ... 0.25 Canesugar ... swe ..» 20.00 
Ferric chloride ~ik ... 0.05 Distilled water uy 1000.00 
This is first heated to dissolve the agar and is then placed in the tubes, 
which are plugged with cotton and sterilized under steam pressure. When 
cool, the nutrient substance is in the form of a jelly, and it is upon this that 
the seed is sown. When sufficiently grown, the seedlings are transferred to 
large flasks, containing the same culture medium as used in the tubes. A. 
