INTRODUCTION 34 
sources ever most generously placed at our command. Іп addi- 
tion to the friends already mentioned, who have communicated 
Californian specimens, our thanks are due to numerous others who 
have kindly loaned types or sent specimens for comparison. We 
are especially indebted in this way to Mr. W. H. Pearson, Professor 
Е. Е. Weiss, Herr Е. Stephani, Dr. В. L. Robinson, Dr. E. Levier, 
Dr. Н. W. Arnell, Sir W. T. Thiselton-Dyer, Professor С. G. Limp- 
richt, Dr. Harald Lindberg, Herr M. Heeg, Mr. Matthew B. Slater, 
Dr. Alexander W. Evans, Professor Romualdo Pirotta, Professor 
Günther Ritter von Beck, Мг. О. Е. Cook and Mons. P. Hariot. 
