Hepaticae : Yale Peruvian Expedition of i^ii. 



307 



here, as in allied species, is strongly and narrowly arched, and this 

 peculiarity, associated with the convexity of the leaves, gives the 

 plants a very characteristic appearance. As the leaves become 

 dry they appear more and more revolute and spread from the axis at 

 almost a right angle. When moist they spread more obliquely and 

 show a strong tendency to come into contact postically. 



Two South American species are closely related to P. Footei. One 

 is' J*, oresitropha Spruce, ^ collected by Spruce in the Andes of Peru 

 and by Rusby in Bolivia, and the other is P. mapiriensis Spruce,^ 



Figure 3. — Plagiochila Footp:i Evans 



A. Leaf, dissected from the stem, X 17. B. Cells from the middle of 



a leaf, X 225. C. Tooth from the postical margin of a leaf, X 225. The 



figures were drawn from the type specimen. 



collected by Rusby in Bolivia. According to Stephani P. mapiriensis 

 is merely a form of the widely distributed P. rutilans Lindenb., but 

 Spruce's description would indicate that he had another species be- 

 fore him. In P. oresitropha the general appearance is much the same 

 as in P. Footei, the leaves being nearly opposite and spreading widely 

 from the stem. Yet the species is somewhat more robust, and the 

 leaves are larger and closer together. Spruce gives as measurements 

 for the leaves a length of 2.5—3.25 mm. and a width of 2—2.75 mm., 

 the ratio of width to length being a little higher than in P. Footei. 

 The leaves show further differences in their teeth and in their cell 

 structure. In P. oresitropha the antical margin bears five or six 

 scattered teeth, only the basal portion being entire, while the teeth 

 on the postical and apical margins are more crowded than in the new 

 species. In fact the whole number of teeth on a leaf is approximately 



^ Hep. Amaz. et And. 467. 1885. 

 2 Mem. Torrey Club 1: 131. 1890. 



Trans. Conn. Aoad., Vol. XVIII. 



21 



Apeil, 1914. 



