Plant identification: San Francisco, USA
I'm going to refrain from giving you the answers because the point of the assignment is to  learn how to do it yourself. 

You should likely start  by using a dichotomous key (likely provided by  your instructor).  

You could also try  searching the Jepson California eflora or CNPS Identifying Native Plants for online keys.  

Check out  the California Native Plant Exchange website if you don't know the name of the plant but know the general area where you saw it. 

If you don't know what general type of plant  you have,   you should try keying  the plants to family  first  to get better search terms.  Try here. 

If you don't know plant terminology  used  in  these keys,  try  "Plant Identification Terminology: An Illustrated Glossary" (Harris &amp; Harris, 2001)