1906] LEWIS—DEVELOPMENT OF RICCIA 121 
the form of a foot. When we consider the fact that some other 
Hepaticae which have the foot well developed grow on very wet 
soil and require as much moisture for their development as do some 
of the species of Riccia, this theory does not seem entirely convincing. 
The sporophyte develops during May and June. A given sporo- 
phyte requires about three weeks for its development. ‘ 
SPOROGENESIS. 
Usually the most favorable cells for the study of cytological details 
are the spore mother-cells. Their large size, abundant contents 
and active growth at the time when divisions are taking place, permit 
good results in fixation. Riccia crystallina has furnished the most 
satisfactory material. 
In July, 1903, an abundance of fruiting Rzccza crystallina was 
found growing on the mud on the bottom of a dried up pond not 
far from the ponds where the form known as Riccia lutescens was 
growing. This species had never been collected in this region 
before. Having so determined the plant, I referred specimens to 
Prof. A. W. Evans who confirmed my determination. He says: 
‘“Apparently this species represents an addition to the hepatic flora 
of New York. I find no mention of it in local lists of New York 
plants and there are no specimens of it from your state in my 
herbarium.” 
These plants had been growing under favorable conditions, as 
the pond had not contained much water at any time during the 
spring. The thalli formed rosettes growing so close together as almost 
to cover the ground. ‘The number of fruiting plants was very 
striking, as it seemed impossible to find a single sterile plant. All 
stages in the development of the sporogonium and spores were 
easily obtained, and some stages in the development of the sexual 
organs, but changes were taking place very rapidly and the younger 
stages were of comparatively rare occurrence. The development 
of the sexual organs and fruit agrees with that of other species of 
Riccia. Each thallus produces several sporophytes which are easily 
recognized when mature as small black spherical bodies imbedded 
in the tissue. 
These plants continued to develop and produce sporophytes for 
only a short time after they were discovered. The month of July 
