— 68— 



yellowish-brown and tawny, orbicular to oval-orbicular, somewhat flattened or 

 discoidal, the surface muricate-reticulate, the reticulations forming a blunt or 

 toothed rim around the edge resembling a crest. 



The most decisive factor in the determination of the species is the form of the 

 elaters. They are very small, short, cylindrical, straight or occasionally slightly 

 curved, the ends very obtuse. There is a single feeble spiral. These characters, 

 according to the rather meager literature at hand at the time for determination, 

 did not accord with any but those of F. crispula of Austin.* 



A favorite place of growth for the plants in the ToUeston locality was the 

 vertical sides of holes left in the mud by the feet of cattle. These were evidently 

 made when the mud of the dessicated slough had reached a consistence that kept 

 it from collapsing and the sides from falling in on the withdrawal of the foot. 

 They were often quite well covered by plants. From its place of growth and its 

 habits, it is evidently an annual, the spores starting the new plant when the 

 ground becomes dry enough for the processes of vegetation. In such situations 

 as these sloughs present, the ground is covered with water for six months or more, 

 from the beginning of the autumnal rains in October or November until evapora- 

 tion by the heat of the summer in June or July, or by its slow escape by seeping 

 through the sands, such sloughs being commonly without surface drainage. 

 Such being the case it becomes a question of interest in what life condition the 

 plants pass the wet season. Unless the holes made by the feet of cattle last from 

 one year to another or through the winter season, as hardly seems probable from 

 their apparent freshness and the soft nature of the bottom, it seems as if the spores 

 survived in the water and, lying or lodging in the bottom, were, so far as the holes 

 were concerned, pressed into them by the hoofs of the cattle. Either the spores 

 must have a structure capable of enduring this long soaking, or, germinating in 

 the fall, the new plant must undergo these submerged conditions. But it is more 

 likely an annual like RicciacecE of similar habit, such as Riccia crystallina, com- 

 mon on the clayey mud, sometimes quite dry and hard, of dessicated pools and 

 sloughs of the region of argillaceous till, and a terrestrial form of Ricciella fiuitans 

 var. canaliculata (Hoffm.) Lindenb. I have found a single station for the latter in a 

 slough by the railroad about a mile east of the Dune Park station. When the 

 water dries away and recedes from its borders, the terrestrial plants can be found, 

 making little rosettes similar to those of R. crystallina, but smaller. The common 

 floating form is seen at the same time on the water or wetter mud. If the sum- 

 mer continues too wet one looks in vain for the fruiting form, the stage of water 

 continuing too high. Like these the Fossomhronia fruits late in the season and 

 appears on the mud after the summer heat has removed the water. In contrast 

 with these it may be noted that Ricciocarpus natans, whose floating forms fruit 

 freely, matures spores in the early summer, as early as June. 



7100 Eggleston Ave., Chicago, III. 



* The descriptions were those of Underwood, one in the 6th edition of Gray's Manual of 

 Botany, the other in his "Descriptive catalogue of North American Hepaticae North of Mexico, 

 published in the Bulletin of the Illinois State Laboratory of Natural History, Normal, Illinois, 

 3 : 60. 1884. 



