GENUS PALLAVICINIA 



METHODS 



Most of the material was killed with a I % aqueous solution of chro- 

 mic acid. Other material was fixed with alcohol containing 10% acetic 

 acid. Larger specimens were also preserved in commercial alcohol. 

 The material was imbedded in paraffin, cut uniformly 6u in thickness. 

 cleared in xylol, and stained variously for the study of different struc- 

 tures. Bismarck-brown proved the best stain for the vegetative parts of 

 the thallus, except the conducting tissue, which was well differentiated 

 by gentian-violet. The latter stain was also found useful in the study 

 of the spermatozoids. These were not satisfactorily stained with either 

 safranine or methyl violet. Haidenhain's iron-alum-haematoxylin proved 

 much the best stain for the nuclei, and was well differentiated by either 

 Bismarck-brown or Delafield's 'haematoxylin. 



Pallavicinia (Mittenia) Zollingeri (Gottsh.) Schiffner. 



Pallavicinia Zollingeri is one of the most striking members of the 

 genus, and has hitherto been collected only from Java and Sumatra. The 

 specimens here described were collected near the summit of Mt. Pan- 

 gerango, an extinct volcanic cone in Western Java, nearly 10,000 feet in 

 height. In this region the plant is very abundant, especially on the low 

 banks along the trail, where it occurs in dense mats of considerable size. 

 It fruits abundantly, and no trouble was experienced in securing an abun- 

 dant supply of material in various stages of development. In May, 191 3, 

 the plant was found on Mt. Banajao, near Manila; and probably the 

 same species was also found in the Benguet mountains. So far as we 

 know, this is the first record of its occurrence outside Java and Sumatra. 

 It grew at a height of about 2,000 metres, under much the same condi- 

 tions as on Pangerango in Java. 



From the slender, creeping rhizome the delicate fan-shaped erect 

 shoots, which are about 6 cm. in height, arise, vivid green in color, and, as 

 we have already stated, resembling so closely a delicate fern that they 

 might very well be mistaken for it (Figs. 1, 5). 



The method of growth is sympodial, the apex of the prostrate main 

 axis turning upward, and developing into the expanded, leaf-like erect 

 shoot. From the ventral side of the shoot, near the base, a branch devel- 

 ops which grows horizontally for a time, as a rhizome, and finally turns 

 upward to form another upright frond. 



The growth of the shoot is due to the activity of a single large apical 

 cell (Fig. 3, A, B). This appears broadly triangular in section, with seg- 



