INTRODUCTION TO CRYPTOGAMIC BOTANY. 567 



affect the erratic blocks scattered over the plains of Germany. 

 Such species as Andrcea Rothii, Gatascopium nigritwm, 

 Grvmmia trichophylla, G. leucophwa, &c., are not species of 

 so low an altitude. The geological bearings of this anomaly 

 are obvious. See Itzigsohn in Bot. Zeit., 1853, p. 601, and 

 1856, p. 913. 



Page 547. — It ought to have been mentioned that the 

 structure of the stem in Botrychium is more nearly that of 

 Ferns than Lycopods. Two or more bundles of scalariform 

 tissue are disposed roimd a central mass of parenchym. In 

 OphioglossuTti vulgatuin the central tissue is wanting, and 

 about five vascular bundles are seated on the walls of the 

 cavity. 



Page 558. — The vascular bundles are sometimes confined 

 less exclusively to the centre in Selaginella. In S. Philippina, 

 Spring, besides the ordinary scalariform tissue, I find true 

 spiral vessels, and the bundles inclined to form a circle, and 

 vessels may probably be found passing from spiral into true 

 annular vessels, as in Equiseta. The normal characters, how- 

 ever, are not affected by such exceptions. 



