PLANT PHYSIOLOGY 159 
should be carefully marked, the shoot set in water and 
left for some days. If the opening buds can be marked 
while still on the tree and left to open naturally it will 
be bettcr, but as a rule the shoot will develop after it 
has been picked, if it is placed in water. 
PRACTICAL WORK. 
t. All the experiments described should be performed and 
the results varefully noted. Note also the time taken, and the 
particular plant used. The Transpiration experiments succeed 
best in the early spring, as do those on Root Pressure, but the 
other experiments can be performed at almost any time in 
this country. 
2. Specimens of Parasites, Saprophytes and Insectivorous 
Plants should be obtained and carefully studied. Dodder and 
Mistletoe occur in many parts of South Africa, so does at least 
one specimen of Drosera; Nepenthes and Sarracenia are fairly 
easy to cultivate in a hot-house, 
3. Xerophytes, Hydrophytes and Epiphytes should be 
studied in their natural surroundings. Almost any kopje will 
furnish numerous examples of Xerophytes, the same place 
should be visited before and after the dry season. The Karoo 
plants are practically all Xerophytes. Epiphytes are plentiful 
in Natal, and can be found anywhere where there are fairly 
dense woods and forests. Hydrophytes should be looked for 
in both still and running water and their characters compared. 
Cut sections of the leaves and stems of Xerophytes and Hydro- 
phytes and note how the internal structure differs from that of 
the typical Mesophyte, such as Sunflower. 
QUESTIONS ON CHAPTER IX. 
1, Give an account of the processes of root absorption. By 
what means are roots able to absorb substances which are 
insoluble in water ? 
2. What is a carbohydrate? Mention the chief carbo- 
hydrates, stating how they are distinguished from each other. 
How are oils and fats distinguished from carbohydrates ? 
