50 



BOTANY. 



of one or more tissues; this redaction may be so great as 

 to leave but a single tissue, which in many cases is com- 

 posed of only a few spiral ves- 

 sels or tracheids (Fig. 32). In 

 other cases, instead of spiral 

 vessels the bundle may consist 

 of a few fibres of bast; or of 

 elongated, thin - walled cells, 

 which are doubtless to be re- 

 garded as meristem-cells which 

 failed to fully change into one 

 of the ordinary permanent tis- 

 sues: this last is a very com- 

 mon accompaniment of reduced 

 bundles. 



Practical Studies. — (a) Break a 

 stem of the Indian corn and note 

 ■with the naked eye tlie tough string- 

 like flbro- vascular bundles wliich run 

 through the soft tissues. Examine 

 in like manner the fibro-vascular 

 vSSlS-T;?X??i'l°?iaTre<S bundles of the common door-yard 

 to tracbeids and spiral vessels. Plantain. 



(6) Make a very thin cross-section 

 of tlie stem of Indian corn and, using tlie microscope, study the bun- 

 dles (.•arefully by comparing with Fig. 35. In bundles from young 

 siirns the fll)rous tissue will not show as good a development as In 

 Irii' fisure. 



(c) Now make thin longitudinal sections of a bundle in such a man- 

 ner as to have the sections pass through a and i in the figure. This 

 may \v done by slicing the stem in a longitudinal radial direction. 

 Study again by comparison with the figure and with the previous 

 specimen. 



(d) Make thin longitudinal sections of a bundle at right angles to 

 the last (by longitudinal tangential sections of the stem). 



(e) Study In like manner the bundles of sugar-cane and asparagus. 

 (/) Study by similar sections the Imndles of the young stem of 



