TRILLIUM 193 



C. The Shoot: 



1. General. 



(a) Note its division into a main, thickened under- 

 ground part (rhizome), bearing numerous roots, 

 and a long slender aerial branch. 



2. The Rhizome. 



(a) Describe its attitude (horizontal or erect), and 

 its general appearance. Compare Trillium 

 with the fern in this respect. 



(b) Are there branches, besides the aerial branch? 



(c) Note the thin membranous scales near the 

 apical end. Record their number and position. 

 Carefully remove them with the scalpel. What 

 purpose may they serve? What is their 

 homology? Make a drawing of one (X i). 



(d) Observe the nodes and internodes. What 

 do the nodes represent? Note the remnants of 

 the old scales at each node. Compare the 

 lengths of the internodes. What is the mean- 

 ing of this? 



(e) Describe any other scars on the rhizome. Are 

 t they on nodes or internodes? What do they 



represent? 



(f) What develops each year at the growing end? 



(g) A plant that is continued indefinitely, from year 

 to year, by means of a persistent root or stem, or 

 both, is a perennial; one that persists for two 

 years only, setting seed and dying at the end of 

 the second season is a biennial, plants that set 

 seed and perish at the end of one season are 

 annuals. Name illustrations of each of these 

 three classes of plants. 



(h) State, with reasons for your opinion, the age 

 of your specimen. 



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