294 CONSERVATIVE ORGANS. [LECT. VII. 



a. If a solid rnonocotyledonous stern, that of 

 a Palm for example, be cut, either longitudinally 

 or transversely, it is seen to consist of an epider- 

 mis enclosing ligneous bundles or cords, more or 

 less symmetrically distributed in a parenchyma or 

 medullary substance. If the section be longi- 

 tudinal, these ligneous cords are observed to run 

 longitudinally, and extend from the base to the 

 apex of the stem, sometimes in straight lines ; 

 but occasionally assuming a zigzag direction, so 

 as to touch each other at different distances : 

 closer together and firmer towards the circum- 

 ference of the stem, and more apart and softer 

 as they approach its centre *. If the section be 

 transverse, the divided extremities of the ligne- 



* Vide Plate 5, fig. 2, 3, 4. Fig. 2 represents the section 

 of a transverse cutting of a Palm, the Ptychosperma gracilis 

 (copied from a plate of Mirbel) ; a. the ligneous bundles 

 closer together, more indurated, and in greater numbers than 

 in the space marked b, in which also, however, they are less 

 distant and more compact in that portion which is farther from 

 the apex of the section, than in that which is nearer to the 

 centre of the stem. 



Fig. 3. A. 'a transverse slice of the scape of the Tiger- 

 flower, Tigridia pavonia, slightly magnified ; the ends of the 

 ligneous bundles being shown by the white dots, which in 

 the natural stem appear on a green ground. 



Fig. 4-. A longitudinal section of the scape of Great Reed- 

 mace, Typha latifolia, showing the ligneous bundles, which 

 in this instance do not inosculate. 



