Juty, 1922.] THE ORCHID REVIEW. 197 
THE GERMINATION OF ORCHID SEEDS 
By J. RAMSBOTTOM, M.A., F.L:S. 
cote probably most Orchid growers are more interested in the 
practical side of seed germination than in the theoretical questions 
involved, the latter are of such great botanical and horticultural importance, 
that any attempt to solve the problems entailed in the processes is certain 
to arouse the interest of both Orchidologist and Botanist. As everyone 
knows, the prevailing idea since the time of Noél Bernard, is that the fungus 
usually present in the roots of any given Orchid, must infect the seed before 
germination can occur. In this country, my friend the late Mr. Joseph 
Charlesworth, was for many years the main upholder of this theory, and it 
is common knowledge, that by introducing laboratory methods into his 
houses, he achieved results that will ensure that his name will always be 
associated with the raising of Orchid seedlings. It will, therefore, be a 
matter of suprise to many that Professor L. Knudson, of Ithaca, has called 
into question the necessity of the fungus for successful germination 
(Botanical Gazette, lxxiii, p. 1, 1922: “ Nonsymbiotic Germination of Orchid 
Seeds”). As hints have already appeared in the horticultural press that the 
end of many of the troubles of the Orchid house is almost in sight, it has 
been suggested that a critical summary of Knudson’s results would serve a 
useful purpose. It may be as well to state clearly at the outset, that even 
if these methods should prove capable of general application, they are just 
as formidable as the so-called ‘“‘ pure-culture” method. The same galaxy of 
sterilisers, flasks, and so on is necessary ; although the root fungus is not 
called upon, there is even more need to prevent contamination of the 
media by the numerous fungi which usually abound in the houses— 
bacteriological cleanliness is essential. 
“The difficulty of germinating seeds of Orchids is due in part to inherent 
causes, but undoubtedly is due also to environtmental factors. The 
extremely small size of the embryo renders it liable to death if it becomes 
desiccated. ... The increasing importance of Orchid culture in America, 
the difficulties in, and the restrictions on the importation of Orchid plants, 
and the desirability of creating new hybrid forms, make particularly 
desirable a method for germinating the seeds.” 
Knudson started from the fact, first ascertained by Bernard, that the 
Seeds of Cattleya and Lelia can be successfully germinated on a 
concentrated solution of salep, and that the seedlings can be transplanted. 
Knowing from his previous experiments on the nutrition of plants, that 
Sugars have a favourable influence on growth, Knudson surmised that they 
might affect Orchid seeds similarly. Throughout the experiments cultures 
were made on agar slopes in tubes, the nutrient solution used being that of 
