19191 ono 



MOORE AND KARRER — A SUBTERRANEAN ALGAL FLORA «51M 



from ordinary garden soil. No tabulated results were kept of 

 these because Protoderma appeared in all of the cultures. 



From the above tables, it will be seen that there exists a sub- 

 terranean algal flora independent of the nature of the soil and 

 the locality. A wide variety of algae does not appear in the 

 soils examined but in most cases the variety is as great as at the 

 surface. The absence of a variety of blue-green algae and the 

 constant occurrence of Protoderma viride is especially noticeable. 

 The fact that the latter occurs at the greatest depth and in every 

 soil seems to indicate that it is especially adapted to live under 



subterranean conditions. 



The greater number of soil samples studied in this investiga- 

 tion is comparable to those termed uncultivated forest soils by 



Esmarch. The 



similar in that he 



found no Cyanophyceae on the surface or underground. The 

 soils in all cases were uncultivated, a fact which may account 

 for fewer cultures showing blue-green forms than reported by 

 Robbins and Esmarch. It is possible that the unicellular green 

 alga reported by Robbins is a form of Protoderma viride. 



As has been pointed out by Esmarch, this flora undoubtedly 

 originated from the surface flora, but its persistence in the soil 

 at such great depths is noteworthy. It is inconceivable that in 

 undisturbed soil compact as clay, algae could be carried down 

 very far by surface waters. There were no evidences of worm- 

 holes or penetration by surface organisms in these soils. This 

 would seem to indicate that the algae are in a vegetative con- 

 dition and actually grow in the soil. 



The amount of growth in the various bottles can be taken to 

 represent in a general way the abundance of the algae in the 

 soil at the different depths, since the cultures were all kept under 

 similar conditions. It was impossible to determine this from a 



:onical examination of the soil samples, because the 



micros 



uch small quantities that they could 



be easily found among 



rowth 



was never at the surface but at a depth of 5-60 cm. This was 

 due probably to the dry conditions existing at the surface. 

 From 60 to 100 cm. the amount of algae in the cultures gradu- 



