1922] KNUDSON—ORCHID SEEDS 13 
of thirty separate measurements. The data are given in table II. 
The slow growth is well shown. There is in general a correspond- 
ing increase with increase in concentration, but the increase in 
concentration beyond o.80 per cent is without any significant 
effect. On February 15 the embryos of all the cultures were 
examined for starch. It was found only in those cultures with 
0.80 per cent glucose or higher. This fact is evidence that the 
absorption of glucose at a concentration of 0.80 per cent is in 
excess of the utilization, and consequently a higher concentration 
TABLE II 
INFLUENCE OF sialon OF ca Sens 2 HYBRID NO. 2;* 
SEEDS SowN Nov. 
AVERAGE WIDTH OF EMBRYOS IN MICRONS 
CULTURE SOLUTION 
December 16 January 11 March 15 
Solution Bisco 126 145 174 
Solution B 0.05% glucose... .. 184 232 247 
Solution B 0.10% glucose... .. 200 252 339 
lutio 20% glucose...... 242 281 475 
Solutio 40% glucose...... 310 291 455 
Solution B 0.80% glucose...... 291 339 533 
Solution B 1.00% glucose... ... 320 417 543 
Solution B 2.00% glucose...... 320 436 523 
* Composition: C. Trianaei Reichb. 4; C. Loddigesii Lindl. 3; L. purpurata Lindl. }. 
should be without any increased beneficial effect. It should be 
borne in mind that glucose used with solution B is not particularly 
suited for the germination of orchid seedlings, since there is induced 
constantly in the embryos a distinct chlorosis. It is probable that 
higher concentrations of sucrose or fructose would permit of a 
more rapid germination. 
The results of several other experiments on the influence of 
different concentrations of glucose on the germination of seeds of 
Cattleya are in agreement with these results, and need no repetition. 
In an experiment with seeds of Epidendron, germination was 
obtained with a concentration of o.2 per cent glucose. In the 
cultures with less than o.1 per cent glucose, not only was there a less 
development of the embryos, but a large percentage of the seeds 
never showed any initial swelling and development of chlorophyll. 
