70 MORPHOLOGY AND LIFE HISTORY 



grow? If it branches, describe- its manner 

 of branching. 



(6) Does the rhizome bear any outgrowths besides 

 the leaves and roots? If so, describe their 

 structure, color, relative number, and location. 



(c) The places on the rhizome where the leaves are 

 borne are called nodes. What is the region 

 between two nodes called? 



Note. The directions below (d-i) apply especially to 

 the bracken fern, Pteris aquilina. 



(d) Observe the end of a rhizome, cut squarely 

 across. If preserved material is used, the cut 

 surface should be kept moistened during the 

 study. The observations may best be made 

 from a piece 5 to 10 mm. thick, cut transversely 

 and placed in a watch-glass of water. Do not 

 cut or injure your specimen in any way, as it 

 will be collected for further preservation at the 

 end of the study. 



(e) Distinguish the following tissue-regions: 



(1) The epidermis (black in preserved material) . 



(2) Underneath the epidermis a narrow, dark- 

 colored region of hypodermal sclerenchyma. 



(3) Within the hypodermal sclerenchyma the 

 fundamental tissue (parenchyma). 



(4) Imbedded in the parenchyma two promi- 

 nent elongate, dark-colored areas, the central 

 sclerenchyma, or stereome (sometimes fused 

 into one). 



(5) Also imbedded in the parenchyma, and sur- 

 rounding the inner sclerenchyma, several 

 areas of fibre-vascular bundles. In fresh 

 specimens these areas are yellowish, in 

 preserved material they are lighter colored 



