The Genus Riccardia in Chile. i6i 



the system shows two simple branches on each side, the basal branch 

 being the longer of the two. These branches are 0.3-0.4 mm. 

 wide and, together with the axis of the system, form a cluster of 

 crowded or overlapping divisions with rounded ends. Unfortu- 

 nately this typical condition, although often approximated, is rarely 

 wholly realized. It is shown by the basal system in Fig. 7, C, 

 part of which is hidden, and approximated by the next system, 

 which shows two branches on one side and one on the other. The 

 two Imsal systems in Fig. y, B, are likewise almost typical. The 

 other branch-systems shown in this figure seem to deviate widely 

 from this description. Many of these systems, however, are still 

 immature and might have acquired a more typical appearance if 

 they had developed fully. The ultimate photo synthetic branches 

 are distinctly winged on each side, the margin being crenulate from 

 projecting cells. The wings are mostly two or three cells wide 

 (Fig. 7, F) but may show a width of four or five cells. According 

 to Stephani the wings are uniformly six cells broad, but the type 

 material does not support this statement. The median portion of 

 an ultimate branch is mostly five or six cells thick. In addition to 

 the photosynthetic systems the axis sometimes gives rise to stolons 

 (Fig. 7, C). These usually grow out from an edge turned toward 

 the substratum and help to attach the thallus more firmly. The 

 stolons show indefinite growth and sometimes bear scattered 

 branches or branch-rudiments. They average about 0.25 mm. in 

 diameter and are only slightly flattened, the median portion being 

 seven or eight cells thick. They sometimes show narrow and 

 interrupted wings, but are usually wingless throughout. Fig. 7, 

 G, which represents the section of a stolon, shows a wing on one 

 side and none on the other. 



Stephani states that a female branch is short and lacinulate and 

 that it gives ofif a male branch on each side at the base. He adds, 

 however, that the male branches are sometimes borne singly at the 

 bases of pinnules, thus implying that they are not always associated 

 with female branches. In the writer's experience the sexual 

 branches arise on entirely distinct individuals, and the species would 

 have been described as dioicous without a doubt, if it had not been 

 for Stephani's account. It is unfortunate that the specific name 

 "autoica" should have been applied to a plant which is not more 

 constantly autoicous. 



