Hepaticae : Yale Peruvian Expedition of ipii. ' 335 



in width ; it consists, as in other species of Chonanthelia, of a water- 

 sac and an appendiculum, each occupying about half its length. 

 Sometimes the lobules do not overlap at all, but frequently the 

 water-sac of one lobule partially covers over the appendiculum of 

 the next younger lobule on the same side. The water-sac is well 

 rounded above, and the inflated portion is restricted to the upper 

 and outer portions. The apex of the lobule extends as a slender, 

 subacute to rounded process directed backwards. The free margin 

 is more or less curved in the inner part and lies closely appressed 

 to the appendiculum. The outer part forms a distinct angle with 

 the inner part and is involute except near the apex, thus forming 

 a narrow, canal-like opening leading into the water-sac. The 

 appendiculum is variable with respect to its outline and the character 

 of its margin. When well developed it consists of a plane or more 

 or less crispate expansion, oblong-rectangular in form, extending 

 beyond the margin of the lobe, and connected with the latter by a 

 long straight keel, which is parallel with the axis and about 0.15 mm. 

 distant from it. The outer angle of the appendiculum is sometimes 

 rounded but more frequently forms a sharp tooth-like point, and 

 additional teeth are developed. The margin at the upper end, 

 near where it joins the apical portion of the lobule , is involute and 

 often appressed to the outer surface of the sac, thus making a more 

 complete closure of the mouth. Although the conditions just 

 described represent the more typical features of the appendiculum, 

 it is not unusual, especially on branch-leaves, for it to be more 

 triangular in form, the base of the triangle being at the junction 

 with the water-sac, the apex at the lower end of the keel. The* 

 stylus is extremely minute and consists of a row of cells tipped 

 with a hyaline papilla. 



The underleaves, which measure about 0.75 X 0.9 mm., are 

 broadly orbicular and more or less imbricated. Except for the 

 apical indentation, the margin is entire or sinuate, although more 

 or less crispate. The line of attachment is slightly arched, and 

 the base is strongly cordate or auriculate, the auricles being some- 

 times so large that they overlap. The apical teeth are from one 

 tenth to one fifth as long as the underleaf; they are more or less 

 sharp-pointed and vary from suberect to connivent, while the 

 sinus is rounded. The basal portion of the underleaf develops 

 a bulging radicelHferous region, which remains rudimentary if no 

 rhizoids are formed. 



The cells of the lobe average about 20 // along the margin, 26 [i 

 in the middle, and 40 X 2(3 /^ at the base. The trigones are large 



