162 
17. What is the cause of the ring- 
like markings seen in the cross-section 
of a tree-trunk? (S8.K.E.) 
18. Describe and explain as much 
of the texture of a deal plank as can 
be made out with the naked eye. 
(S.K.E.) 
19. Describe, with diagrams, the 
primitive structure and the mode of 
growth in thickness of the stem of a 
dicotyledonous plant. Why does the 
stem of dicotyledonous plants usually 
increase in thickness? (S.K.E.) 
20. Explain the modes by which 
stems may increasein diameter. Point 
out the causes of the difference be- 
tween the spring and the autumn wood 
EXAMINATION QUESTIONS. 
of dicotyledonous trees with annual 
growth. (S8.K.A.) 
21. Explain the difference in the 
| growth of the bark of a tree and that 
of the wood. (S.K.E.) 
22. What is the structure of the 
cambium; how does it originate in 
the stem, and to what tissues does it 
give rise? (S.K.A.) 
23. From what source is the starch 
derived which is stored up in a potato 
tuber? By what means has it been 
transported thither? (S8.K.E.) 
24. State what is the tissue in which 
water travels from the root to the 
leaves, mentioning illustrative experi- 
ments. (S.K.E.) 
3. Foliage Leaf. 
25. Describe a bud. To what struc- 
tures do the outer coverings corre- 
spond? What is the origin and use of 
the resinous secretion with which they 
are often covered? (S.K.E.) 
26. How do the outer leaves of a 
bud generally differ from the inner? 
(S.K.E.) 
27. Whatisa leaf? What is its use 
to the plant? (8.K.E.) 
28. Of what parts is a leaf made up? 
What is the use of the leaf as a whole, 
and what are the uses of the several | 
parts? (S.K.E.) 
29. Give instances of foliar organs 
in which only the part corresponding | 
to the petiole of the leaf is developed. 
(S.K.A.) 
30. Describe the nature of stipules, 
and illustrate from British plants the 
forms which these organs may assume. 
(S.K.A.) 
31. What are stipules? Describe the 
stipules of the rose and of the sweet- 
pea. (S.K.E.) 
32. What is the general plan of ar- 
rangement of leaves ona stem? Why 
is it the most advantageous to the 
plant? (S.K.E.) 
33. Give instances in which leaves 
are only imperfectly developed. What 
useful purposes may they serve in such 
cases? (S.K.E.) 
34. Mention, with examples, special 
purposes to which leaves are adapted 
in different plants. (S.K.A.) 
35. Describe the structure of an 
onion. (S.K.E.) 
36. What is the use of the leaf to an 
ordinary green plant? (L.M.) 
37. What components of the atmos- 
phere are taken from it by plants, and 
for what purpose? (S.K.E.) 
38. From what source does a green 
plant obtain its carbonaceous food, and 
in what form and by what organs does 
it absorb it? What are the conditions 
upon which the assimilation of the car- 
bonaceous food depends? (S.K.E.) 
39. Plants are said to ‘‘starve in the 
absence of light.” Explain this state- 
ment, (S.K.E.) 
40. State why absence of light is in- 
jurious to plants. (S.K.E.) 
41. Explain what is meant by trans- 
piration, and state how this process 
may be experimentally demonstrated. 
(S.K.E.) 
42. What is meant by transpiration ? 
Under what circumstances do plants 
transpire most? (S8.K.E.) 
43. Explain why it is that plants 
| droop on a hot day, and recover their 
freshness in the evening. (S.K.E.) 
44. Describe the structure, develop- 
ment, and mechanism of the stomata. 
What is the effect of exposure to light 
upon the stomata? (S.K.A.) 
45. A withered branch on a tree with 
deciduous leaves retains its leaves in 
winter when the living branches have 
lost theirs. Explain the reason of this. 
(S.K. A.) 
46. When a branch is cut off a plant, 
the leaves uponit shortly begin to droop. 
Explain why this happens. (S.K.E.) 
