EQUISETUM 157 



tion. Does their distribution on the rhizome 

 bear any constant relation to the point of origin 

 of the aerial branches? 

 4. Make drawings showing all points observed under 



C, 1-3- 

 D. Asexual Reproduction: 



1. Vegetative Propagation. 



(a) Describe the possibility of the multiplication 

 of new individuals by the isolation of pieces of 

 the rhizome. 



2. Reproduction by Spores. 



(a) Sketch the strobilus or cone (X 3). 



(b) Make a cross-section of the cone at about one- 

 third of the distance from the apex, and observe 

 the central axis, and the manner in which the 

 sporangiophores are borne. 



(c) Carefully dissect off a sporangiophore, and ob- 

 serve (i) its stalk; (2) its peltate (shield-like) 

 top; (3) hanging from the under surface of 

 the shield, the sporangia. How many spor- 

 angia on each sporangiophore? Examine sev- 

 eral sporangiophores to see if the number of 

 sporangia is constant. Describe the dehiscence 

 of the* sporangia. 



(d) Examine the spores under the microscope. 

 Can you detect more than one size; i.e., is 

 Equisetum a homosporous or a heterosporous 

 plant? 



(e) Describe the appendages (elaters), of the 

 spores. How many on each spore? They are 

 formed by a modification of the outer coat of 

 the spore. Observe their behavior when 

 breathed on at frequent intervals. 



(/) While the spores are morphologically homo- 



