THE EMBRYOLOGY AND DEVELOPMENT OF RICCIA 
LUTESCENS AND RICCIA CRYSTALLINA.' 
CHARLES E. LEwis. 
(WITH PLATES V-IX) 
In June 1903, while collecting liverworts in the vicinity of Ithaca, 
N. Y., an abundance of material of Riccia lutescens was found growing 
around the edges of dried-up ponds. In some cases the plants 
formed beautiful rosettes, but usually they grew in irregular clusters, 
often being so closely crowded together as to cover the ground for 
several square centimeters. 
The individual plants vary greatly in shape and size. The 
younger light green plants consist of a narrow, thin, ribbon-shaped 
thallus which has a longitudinal median groove. In the older plants 
the fore part of the thallus is thickened, very large air cavities being 
formed: The thallus is attached to the soil by numerous rhizoids 
from the older part, the apical end being free. On the under side 
are numerous colorless lamellae. 
As the fruiting plant is unknown there is doubt as to the rela- 
tionship of this species, authorities differing widely as to its status. 
LINDBERG (21) claimed that it was merely a sterile terrestrial form 
of Ricciocarpus natans. UNpdERWwooD (30) says of it: “approaches 
certain terrestrial forms of Ricciocarpus natans, and possibly derived 
from that species, but better kept distinct.”” SrEPHANI (28) states 
that it is probably not a Riccia but a sterile marchantiaceous hepatic. 
For the purpose of determining the true relationship of the species, 
Professor ATKINSON suggested the desirability of following the 
development of the plant through the summer and autumn, and 
of securing fruiting specimens if possible. He had found young 
antheridia in plants collected several years before, but had not traced 
the development further. It also seemed desirable to study the 
embryology and cytology of the plant if material could be obtained, 
because comparatively little has been done on these phases of the 
life history of Riccia. 
* Contribution no. 106, from the Department of Botany, Cornell University. 
109] [Botanical Gazette, vol. 4: 
