148 THE ORCHID REVIEW. [Sepr.-Oct., 1919- 
purple introduced by the first cross, the few exceptions being those in which 
yellow was originally present on both sides of the ancestry. 
In ordinary practice crossing is seldom carried out on, such restricted 
lines, because certain desired results can be obtained by substituting some 
other labiate Cattleya for C. Mendelii. It must be remembered that all of 
them are very closely allied, aud in no case are there unknown factors to 
upset calculations. For shape and delicate colouring C. Mendelii leaves 
little to be desired, but for richness of colouring one would prefer to use C. 
Dowiana, in spite of its tendency to shortness of petal and want of full 
expansion. Again, one’s choice is often limited to plants that happen to be 
in bloom at any particular time, and one has to use the best then available, 
a fact which tells in favour of the large collection. 
It is only when working for some special result that experiments have 
to be carried out on such restricted lines, as for example, if one is trying to 
find out what occurs in nature. We should much like to see a few such 
experiments carried out, and it need not be entirely on uneconomic lines, 
even from a purely practical standpoint. One might substitute C. Dowiana 
for C. Mendelii in the above experiment. This would give C. Hardyana, 
but does anyone know the natural limits of this fine natural hybrid ? 
Many years ago we expressed the opinion that the so-called C. Warscewiczii 
Countess of Derby was a form of C. Hardyana, and since then a similar 
remark has been made about the variety Frau Melanie Beyrodt, but this: 
only means that they are derived from the same two species. The 
question should be followed up by raisers. 
panera mere 
Disas IN LEAF-MOULD.—With respect to the question of growing Disas 
in leaf-mould (see p. 129), Mr. H. J. Elwes, Colesbourne, who was formerly 
very successful in growing these beautiful Orchids in an ordinary compost, 
remarks that his experience with leaf-mould has not been favourable, and 
he thinks that success depends chiefly upon the cultural skill of the grower. 
The points he considers as of special importance are as follows: The 
_ admission of plenty of fresh air and light, without exposure to strong sun- 
shine or cold draughts ; constant watchfulness against thrips, as the plants’ 
will not bear fumigation; careful watering ‘and frequent syringing between 
the pots during growth, so that the roots are neither dry nor waterlogged ; 
about three months of partial rest after flowering ; repotting every two years, 
either in autumn or early spring; and a temperature not falling below about 
35° in winter, and not rising above about 75 in summer, with top‘and side 
ventilation all the year round whenever the outside conditions permit. We 
have a very vivid recollection of the way they flowered at Kew a few years 
ago, and greatly regret the recent decline in their popularity, presumably 
owing to difficulties experienced in their culture. 
