4 GENUS PALLAVICINIA 



some of the less known forms must be done before it will be possible to 

 determine the relationships of the different genera of the Anacrogynae. 



At present the classification of the Anacrogynae is in a most unsatis- 

 factory condition, and it is certain that radical changes must be made in 

 the scope of certain genera, and in the grouping of the families as they are 

 at present constituted. 



Most of the Anacrogynae are plants of relatively simple structure, 

 being thallose forms for the most part, although in certain genera, e. g., 

 Blasia, Fossombronia, Treubia, leaf-like marginal lobes are present ; and 

 the transition from the typically thallose Anacrogynae to the much more 

 numerous leafy liverworts (Jungermanniales acrogynae) is by no means 

 an abrupt one. 



During a stay in Western Java, in 1906, a number of rare liverworts 

 were collected, including several species of Pallavicinia. Among these 

 were three which have been seldom collected, and which so far as we 

 know have never been critically examined as to tiheir anatomy and develop- 

 ment. As it was thought that a careful study of these species might 

 be of value for a better understanding of the morphology of the genus, 

 the specimens were given to Miss Williams for investigation. The 

 making of the preparations upon which the present paper is based, as 

 well as most of the drawings, are the work of Miss Williams. 



The genus Pallavicinia as understood by Schiffner [1], comprises 

 the two old genera, Morkia and Blyttia, of Gottsche. In his recent 

 excellent resume of the Liverworts, Cavers [2] has expressed the opinion 

 that these older genera should be revived, and the name Pallavicinia be 

 discarded. Should this view be accepted, all of the species here con- 

 sided would be transferred to the genus Blyttia, unless the sub-genus 

 Mittenia is separated as a distinct genus. 



Most of tjhe species of Pallavicinia are found in the moist tropics, 

 being especially abundant in the more elevated regions. Several species, 

 however, e. g., P. Lyellii, occur in the more humid parts of the temperate 

 zones. 



Stephani, in his review of the Hepaticae [ 1 ] , recognizes 29 species of 

 Pallavicinia, which are placed in two sections: Procumbentes, 1 with 20 spe- 

 cies, and Dendroideae, 2 with 9. In the Procumbentes (Eupallavicinia) the 

 plant is a prostrate thallus (Fig. 1, B), usually attached for its whole length 

 to the substratum by numerous rhizoids. The members of the section Mit- 

 tenia have the thallus differentiated into two parts, a prostrate rhizome-likc 



''The section procumbentes = Schiffner's sub-genus Eupallavicinia. 

 2 The Dendroideae = Mittenia Gottsch. 



