The Genus Riccardia in Chile. 125 



rather abruptly into the wings, which are three cells thick through- 

 out most of their extent. The surface-cells are like those of the 

 median portion, but the trigones at the upper end are more likely 

 to be coalescent and to take part in the formation of the low papillae 

 which the cells develop. The inner layer of the wing is composed 

 of short cells and represents a continuation of the short-celled 

 second layer of the median portion. Along the edges the wings 

 are bordered by a distinctly differentiated row of hyaline cells, pro- 

 jecting slightly as crenulations. 



At intervals of 1.5-3 cm, the axis gives rise to photosynthetic 

 branch-systems (Fig. i, F), just as in R. preJiensilis. The branch- 

 systems are often approximated in pairs but not invariably so, and 

 are soon limited in growth, attaining a length of 5-10 mm. Each 

 system is narrowly ovate in outline ; it consists of a distinct primary 

 axis bearing at close intervals a series of secondary branches. 

 These decrease gradually in length and are usually simple, but in 

 some cases one or two of the secondary branches on each side will 

 form one or two very short tertiary branches. On the whole the 

 photosynthetic branch-systems are less complex than those of R. 

 preJiensilis and apparently show no tendency to be decurved toward 

 their extremities. Neither stolons nor new axial branches have as 

 yet been observed. 



The primary branches of a photosynthetic branch-system are 

 mostly 0.75-0.9 mm. wide, while the secondary branches are only 

 0.4-0.6 mm. wide. All the branches show distinct wings, which 

 are continuous with one another and also with the wings of the 

 main axis. In the ultimate branches (Fig. i, H) each wing is 

 about one third the width of the branch and is essentially like the 

 wings of the main axis. The cells, however, are a little larger than 

 those of the median portion of the axis, the surface-cells measuring 

 about 40 X 25 /A and the interior about 30 x 25 fi. The interior of 

 an ultimate branch, just as in R. prehensilis, is occupied by a nar- 

 row band of thick-walled cells. Although the projecting surface- 

 cells, both on the wings and elsewhere, tend to give the plants a 

 velvety appearance, this is often scarcely apparent, owing to the 

 slight projection of the papillae (Fig. i, I). In some cases, in 

 fact, the cells scarcely project at all. 



The inflorescence of R. Savatieri is dioicous, but the material at 

 the disposal of the writer is so incomplete that only one plant of 



