34 



PRELIMINARY STUDIES. 



new growth as one, count back five internodes of the 

 stem. Make a transverse section of the fifth internode. 

 Count the number of annual layers of wood. Repeat 

 with other internodes. How do the numbers of annual 

 layers compare with the numbers representing the inter- 

 nodes? How could you tell the age of a given part of a 

 Pine branch without cutting it ? 



7. Examine prepared microscope slides and photo- 

 micrographs of cross sections of Pine and Spruce stems. 

 The arrangement of the wood in a complete circle about 

 a central pith is the rule in the Gymnosperms. 



THE FLOWERLESS PLANTS. 

 The Ferns. 



1. Examine entire plants of as many of the following 

 Ferns as may be convenient: any variety of Adiantum, 



Asplenium, Aspidium, 

 Polypodium, Osmunda, 

 Pteris, and Onoclea. 

 Do this in the field, if 

 possible ; otherwise in 

 the laboratory. 



Only the leaves rise 

 above ground. Obser- 

 vation of the leaves as 

 they uncoil in the spring 



FIG. 13. Transverse section of stipe of 



should be made. The 



Cinnamon Fern, Osmunda dnnamomea. lar g e underground por- 



(x 35.) The curved figure is the fibro- tions are the stems, here 

 vascular bundle. ,, , ,. , 



called rhizomes. Branch- 

 ing from these are small fibrous roots. In removing the 

 specimens from the ground, be careful to injure the 

 rhizomes and roots as little as possible. Compare the rhi- 



