104 



MEDULLOSEAE 



[CH. 



in fig. 419 is based has been investigated by Weber and Sterzel 1 

 and by Solms-Laubach 2 . The figure is a slightly simplified 

 version of that given by Weber and Sterzel; it represents the 

 stem of Medullosa Leuckarti as a transparent object, the two 

 lower transverse sections, B and C, being seen in perspective through 



n 



FIG. 419. Medullosa Leuckarti. Diagrammatic sketch of stem showing longi- 

 tudinal and transverse sections: for explanation see text. (After Weber 

 and Sterzel.) 



the longitudinal faces. The steles are shaded obliquely in the 

 longitudinal sections, and in the three transverse sections, A, B, C, 

 the primary xylem (partial pith) is black and the enclosing 

 secondary vascular tissue radially shaded. The whole block is 

 9 cm. in length and 6 cm. broad. Only a part of the axial region 

 is shown internal to the peripheral snake-rings and in it are the 

 star-rings S, S, b, and c. Outside the main steles is the narrow 



1 Weber and Sterzel (96) B. p. 95, PI. ix. 



Solms-Laubach (97). 



