32 STUDIES OF PLANT LIFE. 
sporophyls. Do they have stalks or are they 
sessile ? 
3. Of how many sides does the distal flattened portion 
of a typical sporophyl consist? Why? 
4. Observe the form and position of the sporangia. 
What do they contain? 
5. With h.p. study the spores. What is their form, 
color, and structure? Observe the thread-like 
appendages (elaters) of the spores. 
6. Make drawings: (a) a distal end view of a typical 
sporophyl; (6) a side view of a sporophyl; 
(¢) one or more spores showing the elaters closed 
and extended; (d) a side view of a strobilus. 
C. Life Problems. 
1. Does it ive more than one year? Why? 
2. Are the leaves more or less important in the work of 
photosynthesis (carbonfixation) than the stem? 
Why? 
3. What conditions of soil favor the growth of horse- 
tails? Why? 
4. There are many related forms. How do they differ 
in general appearance from the one studied? 
5. Of what use are horsetails? 
6. How does its life history differ from that of the 
fern ? 
