30 MISSOURI BOTANICAL GARDEN. 



Cladophora sp., Pleurococcus vulgaris, and Stigeoclonium 

 tenue are the only forms found on the rocks themselves. 

 Pleurococcus grew on all the rocks presenting a saturated 

 surface, except the cement falls and Cladophora grew below 



XII 



base of 

 Cladoph 



which grew on the rocks of the Lagoon. Stig- 



onium was 



water ran rapidly or struck breaking into spray; especially 

 where it fell perpendicularly on a horizontal surface, these 

 being the points of greatest aeration. A few small plants 

 sparsely scattered were found on the perpendicular surfaces 

 of the two cement waterfalls X and XII over which the wa- 

 ter ran slowly in an unbroken stream. Whether the unde- 

 sirabilitv indicated bv the absence of vegetation here was due 



f 



So far as water is concerned 

 where Cladophora and Pleu 



but none appeared here. Stigeoclonium tenue grew abund- 

 antly on waterfall I all winter, but by the 16th of May was 

 quite degenerate, the fall becoming covered with small 

 leeches. S. tenue was noted on all of the falls but X, whose 

 face was shaded by cat-tails and IX, over which the water 

 ran sluggishly with little fall. All the other forms found in 

 the intervals of the stream between the falls have been noted 

 in the Fountain pond with the exception of Hydrodictyon, 

 which probably originated there. It grew in a tangle of fila- 

 mentous forms among the stems of cat-tails. 



The Lagoon is a long, irregular body of water 130x540 



approximately 12 ft. max 



the 



west side and slopes gradually toward the east. This larger 

 body of water yields slowly to temperature changes, freezing 

 later than the upper pond. On cold mornings when the small 

 pond had a fringe or thin coating of ice the lagoon had none. 

 The greater size makes the force of the wind of more import- 

 ance here as waves starting from one side on reaching the 

 other beat the floating fronds against the earth. Oedogonium 

 is abundant on the shallow east side of the lagoon. The 





