302 
Kisch. — The Physiological Anatomy of 
that the periderm was an empty, air-filled tissue, as is the cork of recent 
plants. Of course a very large number of the cells are empty, while others 
contain black lumps, such as may also be seen in the xylem, or are coloured 
brown in large patches. But cells with traces of apparently real contents 
are also found, some types of which are illustrated in Text-fig. 14. Of these 
the appearance of one cell of B may have been produced by the mycelium 
B 
E 
Text-fig. 14. Types of the contents of periderm cells. A, Lepidodendron selaginoides. 
U. C. L. Coll., A 0122. B, Sigillaria scutellata. U. C. L. Coll., B n. C, Lepidodendron fuligi- 
nosum. U. C. L. Coll., A 32. D , Stigmaria. U. C. L. Coll., D 8. E, Lepidophloios sp. U.C.L. 
Coll., A 39 c. x 265. 
of a fungus. 1 In E certain of the cells have an even brown stain, which may 
represent tannin or a like substance, while the contents of the periderm 
of Lepidodendron Wunschianum in tangential section have also been com- 
pared in appearance to vacuolated tannin. 2 Tannin and its decomposition 
products may, however, be found also in true cork. 3 
1 Cp. Lignier (16), p. 197, Fig. 4. 2 Seward and Hill (29), p. 916, PI. Ill, Fig. 20. 
3 Haberlandt (13), p. 124. 
