L32 



tact with the wet soil develop rhizoids, ventral scales, and open air chambers, 

 while those whose apical ends do not touch the soil dry and BOOH die, giving 

 some shade to the delicate plants below. My observations have no! been 

 conducted over a sufficient period of time to determine fully whether these 

 plants produce sex organs and fruit as some observers would have us think 

 actually occurred. In the Deming ponds east of the city limits of Terre 

 Haute aquatic R. fluitans grows abundantly. During the summer and 

 autumn of 1913 these loess encircled ponds became dry due to the long 

 continued drought; however, many thalli remained alive in wet shaded 

 places throughout the dry season. These plants remained in contact with 

 the earth sufficiently long to fruit, judging from experiments made upon other 

 Riccia, however, no sporophytes were found. When weather conditions 

 were more favorable for hepatic growth searches were made for rosettes and 

 thalli typical of terrestrial R. fluitans but none Avere found, indicating that 

 spores had not been produced or had not had time to germinate. Weather 

 conditions of 1914 were similar to those of the fall of 1913. At intervals 

 during the autumn frequent observations were made but yielded no satis- 

 factory evidence. Again in 1915 careful searching was done, without gaining 

 additional results. Similar observations were made at Rosedale in the 

 "Niggar Lake" region, no rosettes or thalli on the mud were found. Judging 

 from these observations it seems very doubtful if the aquatic form ever 

 changes into the terrestrial form or fruits but reproduces vegetatively only. 

 It is very doubtful if the so-called terrestrial R. fluitans and the aquatic 

 R. fluitans belong to the same species. 



The terrestrial R. fluitans is not common in this region; however, it occurs 

 in small patches on mud flats and wet fields during the autumn. It generally 

 grows in rosettes due to the fact that the spores are not scattered but held 

 within the archeground pit, and that the sporophyte is generally buried in 

 the mud. The thalli are about one-quarter inch long and less than an eighth 

 of an inch wide. The plants have a characteristic green which is tinged 

 with purple late in the autumn. Numerous rhizoids develop from the ventral 

 side. A single row of scale leaves which split into two rows grow just beneath 

 the apical cell. The most prominent ventral mark of identification is the 

 protruding sporophyte. The dorsal surface is cut by a furrow which deepens 

 at the apical end into which the pores of the alternating sex organs open, and 

 down which the sperms are carried by moisture. Above the fertilized egg 

 develops a tongue-like projection which covers the mouth of the arche- 



