Spirogyra sp. (POND SCUM, GREEN SILK)* 



A. Classification: 

 Division I. Thallophyta. 



Subdivision I. Algae. 

 Class II. Chlorophyceae. 

 Order. Conjugates. 

 Family. Zygnemaceae. 

 Genus. Spirogyra. 



Species, sp. (i.e., not determined). 



B. Habitat: 



Ascertain from your own observations and from the 

 text, and record at this point in your notes, the habitat 

 of Spirogyra. 



C. Physiology: 



1. Explain, clearly but concisely, how the bodily form 

 of this plant is maintained. Account for any 

 variations in the shape of the cells. 



2. Do you find any roots or other organs for anchoring 

 the plant to the substratum? Do you think the 

 plant is suitably organized for growing in running 

 water? Explain. State a reason why roots are 

 not necessary for this plant. 



3. Explain the presence or absence of stomata. Do 

 you find a cuticle ? 2 Is photosynthesis possible with 

 Spirogyra? Respiration? Explain. 



1 The morphological characters of this plant have already been studied 

 (pp. 11-15). They should now be carefully reviewed, preparatory to the 

 consideration of the physiology and reproduction of the plant. 



2 True cuticle does not occur, but a modification of the outer portion 

 of the cell-wall, called the sheath, and which gives the plant its slippery 

 "feel," is similar to cuticle, though not identical with it. This sheath 

 is difficult to observe directly, though it may sometimes be identified on 

 the outside of the filament at the places where the cross- walls occur. 



