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MANUAL OF NATURE STUDY. 
i. e., in monoecious prothallia, two organs called 
the antheridium and archegonium; the former 
answering to the stamens or anthers in the flower¬ 
ing plant, and the latter to the pistil or ovary. 
In other words, the antheridium is the male re¬ 
productive organ of the plant, and the archego¬ 
nium the female reproductive organ. As the 
pollen-tube of the flowering plant must reach 
the ovule for fertilization before the latter is ca¬ 
pable of development, even so must the energiz¬ 
ing influence of the spermatozoid fertilize the egg 
cell of the archegonium. Soon after this union, if 
the weather is favorable, a young fern plant starts 
out from the archegonium, and as soon as the fern 
is firmly established the prothallium withers away. 
The bean plantlet, you remember, draws its first 
nourishment from the cotyledons or seed leaves, 
and does not depend upon the soil until the 
best part of the food in these leaves is used up. 
The same may be said of beechnut or any flower¬ 
ing plant. In the young corn plant the *albu- 
men gives it the first start. Now the prothallium 
of the fern answers that purpose precisely. Two 
growing points start out from the archegonium at 
the same time; one is the leaf point and the other 
the root point; but the leaf point grows the faster, 
obtaining its food from the prothallium. As soon as 
♦The word endosperm, is preferable. 
