Evans: Hepaticae from Florida 181 



ton 8j). In everglades near Camp Longview {Small & Wilson 

 iJ2o). No. i^ii may be designated the type. 



The leaf-cells o{ P. Smallii are somewhat variable with respect 

 to the size of their trigones ; even when very small, however, 

 these structures can be easily demonstrated in leaves which are 

 spread out flat. In some specimens the trigones and intermediate 

 thickenings are more or less confluent, and this is especially likely 

 to be the case along the inner side of the marginal cells, where the 

 walls often present the appearance of being uniformly thickened 

 (figure 5). 



As one would naturally expect, the species has several allies 

 among the numerous species of Plagiochila found in the West 

 Indies. Apparently the closest of these is P, diffusa Steph.,* a 

 Cuban plant collected by Wright and distributed in his Hepaticae 

 Cubenses. This species, however, is smaller and more delicate 

 than P. Smallii^ its leaves are shorter and relatively broader, the 

 margins being more curved, the trigones of the leaf-cells are com- 

 monly indistinct, and the spine-like teeth at the mouth of the 



perianth are shorter. 



diffi 



very much the same as in P, Smallii ; the line of insertion is 

 sharply arched as in the majority of the Plagiochilae, and the 

 leaves are consequently shortly but distinctly decurrent on both 

 sides : Stephani's description would hardly indicate that this was 

 the case. 



Among other related species the following may be especially 

 mentioned : P. Wrightii Steph.,']' P. ta7nariscina Steph.J and P. 

 tenuis Lindenb. § The first of these is known from Cuba only j 

 the second has been found in several of the West Indian islands ; 

 the third is still more widely distributed, its range extending into 

 South America. In P. Wrightii the leaves are relatively broader 

 than in P. Smallii and are rounded rather than truncate at the 

 apex, a difference to be seen especially well in the perichaetial 

 bracts. The inflorescence is almost always subtended by an In- 

 novation, and the bracts are crowded and in several pairs. P. 



^ Bull. Herb. Boissier II. a : 870. 1902. 



•f L, c, 681. 



X L. c. 6S5. 



\ Sp. Hepat. Plagioch. 50. //. 10, 184I. 



