38 PISTILS AND STAMENS 
mature pod is threshed, only one seed is found. In Alfalfa only 
about one third of the ovules produce seed. In the Apple, Pear, 
Tomato, and other fruits some of the ovules often fail to develop, 
and in case of seedless fruits none of the ovules complete their 
development. In most fruits the production of seed is not an 
important feature to the plant grower, the seedless fruit in many 
cases being more desirable; but in case of Clover, Alfalfa, Flax, 
and other plants valuable for seed, the value of the plant as a seed 
producer is directly related to the number of ovules which be- 
A, B 
Fic. 44. — Surface view of an ovule 
at two stages of development. A, Fic. 45.— Section through 
stage of development showing the the ovule of Red Clover show- 
integuments (a, b) growing up over ing the embryo sac. em, em- 
the nucellus (nm). B, older stage in bryo sac with the egg (e) and 
which the integuments have closed the primary endosperm nucleus 
over the nucellus, leaving only a (en) indicated; i, integuments; 
small opening, the micropyle (m). s, m, micropyle. Many times 
the funiculus. Much enlarged. enlarged. 
come seed. How much could the seed yield of Clover and Alfalfa 
be increased if they could be made to develop all of their ovules 
into seed? If clover seed were selling at $10 per bushel, what 
would be the value of the increased yield on ten acres of average 
Clover? 
Parts of the Ovule. — The ovule consists of a main body and 
a stalk known as the funiculus which connects to the ovary wall. 
The main body consists of a central (usually rounded) portion 
called nucellus, which is enclosed by one or more coverings called 
integuments that grow up from the funiculus. In Figure 40, 
showing the ovules of Clover, the stalk or funiculus is at st; the 
central portion or nucellus of the main body is at n; the coverings 
or integuments of the nucellus are at ?. Turn to this Figure and 
point out these parts. In the ovule of the Corn, shown in Figure 
41, the funiculus is apparently absent. In Figure 44 is shown a 
