£0 ELEMENTS OF AGRICULTURE. 
branch, and those with stamens on another; but with 
hemp, for instance, these reproductive organs are upon 
different stalks. When the two organs are found upon 
the same stalk, though in different flowers, they are called 
monoecia (one-housed plants) ; when upon separate and 
distinct stalks, dioecia (two-housed plants). 
41. When plants of the same family are cultivated in 
the vicinity of each other, it frequently happens that 
their produce differs from the parent plant, because it par¬ 
takes of the nature of both. This is particularly the case 
with the cabbage family. We then say tha't hybridation 
has taken place. Hybrid plants, in the vegetable kingdom, 
are what mules are in the animal kingdom, 
OTESTIONS. 
1. What is meant by organs of reproduction ? 
2. Which are the most essential ? 
. 3. What is a pistil ? 
4. Where are the stamens ? 
5. What is the pollen ? 
6. What is the germ, or ovule ? 
7. What is the fruit ? 
8. What plants are called hermaphrodites ? 
9. What monoecia 1 
10. Plants called dioecia, what are they ? 
11. What is the meaning of hybridation ? 
LESSON VII. 
FRUIT. 
42. A. fruit is divided into two parts: 1. The_pe> carp . 
2, The seed. 
43. The pericarp is that part which, in a pear or an 
apple, is destined to be eaten. In the interior of the peri¬ 
carp exists a cavity, lined with a thin membrane. It is in 
