1922] SPESSARD—LYCOPODIUM 303 
The prothallia of L. Jucidulum are ideal for a study of sex organs, 
since they are long dorsiventral plants with the organs mixed and 
growing acropetally from the apex. The main stages of both 
organs have been secured in a single section. This is rather rare, 
of course, but a comparatively few sections give one surprisingly 
good results. Since they can be secured very easily in the field 
because of their abundance, no other prothallia of Lycopodium offer 
so many advantages at once for class demonstration and labora- 
tory material as these. 
Lycopodium lucidulum 
Since the prothallium of this species of Lycopodium was not 
known previous to my original brief description, it will not be out 
of place to give a rather detailed account of it. 
LOCALITY 
Out of a total of more than 500 prothallia of L. lucidulum which 
were found, only about half a dozen were gathered outside the 
small region just north by several hundred yards of the Ridge 
Street Cemetery at Marquette, Michigan. Evidence of the 
existence of them was found at Mid-Island Point, Sugar Loaf 
Peak, Negaunee, Munising, Ishpeming, and Michigamme. There 
is no doubt that any region of the upper peninsula of Michigan 
will yield prothallia, providing, of course, that it is in general a 
habitat for the species. It is only because the present investiga- 
tions were confined to a careful examination of a very limited 
region that a larger range cannot be given here. This limitation 
was made primarily to determine the relative abundance of material. 
OCCURRENCE 
This species of Lycopodium produces prothallia in remarkable 
abundance. It is only necessary to become acquainted with the 
habitat and to exercise a due amount of patience and vigilance, to 
obtain a gratifying supply. All the prothallia were found within 
an area not more than 25 m. square. Within this area there were 
three especially rich patches, although these were not all discovered 
the same season. One was found in May, another in September, 
and the third in June of the following year. One patch measured 
