THE STEM 111 
contains sugar, which is chiefly for distribution of the 
seed, but may form humus. 
ON 
QUESTIONS ON CHAPTER IV. 
. Compare roots and stems with regard to structure, 
function, tropisms. 
. Give examples of herbs, shrubs, and trees. What points 
of likeness and difference do you note? 
. How would you distinguish the poplar, oak, willow, ash, 
and elm in winter time? 
. Describe the means by which plants elimb. What is the 
advantage of the climbing habit? 
. Define tuber, bulb, corm, rhizome, stolon, sucker, runner, 
off-set. What is the advantage of the rhizome habit? 
. Deseribe the structure of an onion bulb and of a potato 
tuber. 
6. Deseribe the stools of the dahlia and canna. 
18. 
i: 
. Compare one-year old, three-year-old, and ten-year-old 
stems of any available tree. 
. What are the advantages and disadvantages of prostrate 
stems? Deseribe any prostrate stems you know. 
. Draw sections of one-year old monocotylous and dicotyl- 
ous stems. Compare the arrangement of the tissues. 
. What advantage have hollow over solid stems? 
. Describe the structure of an ordinary bud. 
. Compare spring and autumn wood. 
. In what plants are the stems eaten, and in what others do 
the stems yield useful substances? 
. Give a tabular classification of stems. 
. Distinguish epiphytes and parasites. What are the com- 
monest epiphytes and parasites in New Zealand? 
. What are the functions of bast, wood, cortex, and 
epidermis? 
. How would you distinguish the following trees in winter: 
—ash, pinus insignis, plum, apple, pear, peach? 
Name three native trees with which you are familiar. 
Describe their habit, branching, buds, and bark. 
What is a growing-point? Compare the growing-points of 
roots and stems. 
