141 



3. Pileus azonate ; spores white. L.ajjim Pk 

 Pileus zonate or subzonate. 4 



4. Stipe scrobiculate-spotted, hollow. L. insulsus Fr 

 Stipe smooth, not spotted, solid. L. zonarius (Bull.) Fr 



5. Stipe spotted, hollow ; pileus gray or grayish-lilac. L. maculatus Pk 

 Stipe not spotted (or rarely so in L. trivialis). 6 



6. Lamellae staining when wounded. 7 

 Lamellae not staining. ■ 9 



7. Pileus gray with pink or lilac shades ; lamellae staining greenish. 8 

 Pileus gray with greenish shades ; lamellae staining cinereous. L. blennius Fr 



8. Pileus 5-18 cm.; stipe 2.5-15 cm. long. L. trivialis Fr 

 Pileus 2.5-5 cm.; stipe equal to or longer than diameter. L. trivialis gracilis Fk 



9. Lamellae and spores white ; stipe 5-7 cm. long. L. cinereits Pk 

 Lamellae and spores yellowish ; stipe 4 cm. long. L. acer (Bolt.) Fr 



New York Botanical Garden. 



THE PITH CELLS OF PHYTOLACCA DECANDRA * 



By Henry Kraemer 



The structure of pith cells is so characteristic and so constant 

 for certain species and genera, as was pointed out by Gris, that 

 it will in all probability be found to have a taxonomic value 

 in deciding the position of a number of more or less disputed 

 genera and families. While the anomalous structure of the root, 

 stem and leaves of certain species of Pliytolacca has been more 

 or less carefully studied, the pith cells of Phytolacca decandra 

 are so marked in character as to warrant our attention in this 

 connection. 



The pith of this plant is unusually large, its diameter being 

 about five sixths that of the entire stem. The active pith cells are 

 more or less hexagonal in transverse section, the diameter being 

 about three times that of a longitudinal section. The protoplasm 

 lies near the walls and contains a number of chloroplastids and a 

 single nucleus, and surrounding the latter are not infrequently a 

 number of plastids. Some of the cells, which are either nearly 

 isodiametric or considerably elongated, have the large vacuoles 

 replaced by raphides and a small amount of mucilage. The 



* Read before Section G of the American Association for the Advancement of 

 Science, Pittsburg, July 3, 1902. 



