246 
METHODS IN PLANT HISTOLOGY 
In the third edition of this book, published in 1915, the statement 
was made that no one had yet discovered prothallia of Lycopodium 
in the United States. Two years later, a teacher in the high school 
at Marquette, Michigan, Dr. E. A. Spessard, announced the discovery 
Fig. 78 .—Lycopodium lucidulum: photomicrograph of transverse section of stem near the 
apex. The five deeply staining groups of thick-walled cells are the protoxylem and alternating 
with them are groups of phloem cells; the large, thin-walled cells are metaxylem.- Eastman Com¬ 
mercial Ortho film, Written E filter (orange); arc light; Spencer 4-mm. objective. N.A. 0.65; 
ocular X6; exposure, seconds. Slide by Dr. J. J. Turner, negative bv Dr. P. J Sedgwick 
X360. 
of the prothallia of four species (.Botanical Gazette , 63:51-65, 1917) 
and gave such clear directions for finding prothallia that already 
two papers have appeared, announcing the discovery of prothallia. 
One of these papers, by Dr. Alma Stokey and Dr. Anna Starr 
describes seven stations for prothallia in Massachusetts; and the 
