Hepaticae : Yale Peruvian Expedition of igii. 331 



it is often more or less adnate to the auricles of the underleaves. 

 The writer has been unable to demonstrate this adnation, even 

 on robust plants, although it might perhaps be hazardous to maintain 

 that it never occurred. In any case, however, the adnation is too 

 inconstant to be considered a differential character of importance. 



The underleaves are about as large as the lobes and agree with 

 them in being densely crowded. They are broadly orbicular or 

 reniform and are attached by a slightly arched line. The two 

 sharp apical teeth are separated by a lunulate sinus and are usually 

 less than one fourth the length of the underleaf. The teeth are 

 commonly connivent and tend to be more or less twisted or con- 

 torted, while the margin of the sinus is often revolute. Somewhere 

 between the bottom of the sinus and the line of attachment the 

 underleaves form a short and rounded tubular projection, at the 

 tip of which the rhizoids are developed. At the base the under- 

 leaves are strongly auriculate on each side. The auricles are much 

 like those on the lobes. They are often more or less crispate and 

 may be so dilated that they partially cover over the line of attach- 

 ment of the underleaves. Sometimes the crispate nature of the 

 auricles is so exaggerated that incomplete water -sacs are formed. 

 It will at once be noted that the auricles of the underleaves, the 

 auricles of the lobes, and the expanded portions of the stylus are 

 all very similar structures and that through them the capacity 

 of the species for holding water by capillarity is greatl}^ increased. 

 And it is precisely these structures which attain their highest 

 development in markedly xero phytic localities. 



The cells of the lobe average about 23 /< along the margin, 33 /^ in 

 the middle, and 43/^ at the base. The trigones are large and weU 

 developed, showing a triangular form with straight or bulging 

 sides (Fig. 9, E). They are rarely confluent, and intermediate 

 thickenings are almost never present. On the lobules and under- 

 leaves the cells are smaller, but the trigones are relatively larger, 

 more irregular in form, and more frequently confluent. 



Nees von Esenbeck does not describe the type of inflorescence 

 found in F. gibbosa and makes no mention of the male spikes, and 

 the later descriptions would indicate that the inflorescence is 

 subject to variation. According to Gottsche it is dioicous, according 

 to Spruce it is normally autoicous but is paroicous in the variety 

 densissima, according to Stephani it is monoicous, that is, autoicous. 

 When the writer examined the Mexican specimens in the Linden- 

 berg herbarium the conclusion was reached that they were dioicous 

 and that the statement of Gottsche was correct. Since, however. 



