MODIFIED PLANT STRUCTURE. 
— 
Stems or Shoots.—The modified underground stems 
of Solomon’s-seal and Irish potato have already been 
studied. Review the work done on these. As examples 
of others, study tendrils of grape vine, woodbine and 
Japanese ivy, the so-called leaves of green-house smilax 
and stems of cacti, the thorns of honey locust and thorn 
apple. Why call these structures stems or shoots? What 
is the function of each? Draw a specimen of each. 
Leaves.—As examples of modified leaves or portions 
of leaves, study the leaves of a pitcher plant and onion; 
the spines of barberry, common locust and common this- 
tle; the tendrils of wild smilax and pea; and the petioles 
of poplar, Nasturtium and Solanum jasminoides. What 
has been modified in each case to form these structures? 
What is the function of each? Draw a typical specimen 
of each. 
Modified organs found in flowers will be studied 
later. 
Roots.—Roots become much less modified than 
stems and leaves. Can you see any reason for this? 
As examples of modified roots we have studied enlarged 
roots and aerial roots. Review the work done on them. 
Literature. 
Strasburger: Text Book of Botany........... 22-27, 34-36, 42-43 
Stevens: Introduction to Botany................... 134, 136-146 
Geddes: Chapters in Modern Botany............cccecceeees 1-57 
