It is called an "antheridium," and within are produced, by internal division, numerous excessively small spermatozoids.    From Wordnik.com.  [Elements of Structural and Systematic Botany For High Schools and Elementary College Courses] Reference

The oögonium is formed above, the antheridium below.    From Wordnik.com.  [Elements of Structural and Systematic Botany For High Schools and Elementary College Courses] Reference

C. Longitudinal section of antheridium; st, stalk; w, wall.    From Wordnik.com.  [Encyclopaedia Britannica, 11th Edition, Volume 4, Part 3 "Brescia" to "Bulgaria"] Reference

The antheridium consists at first of a basal cell and a terminal one.    From Wordnik.com.  [Elements of Structural and Systematic Botany For High Schools and Elementary College Courses] Reference

Unlike the antheridium, the oögonia contain a great deal of chlorophyll, appearing deep green.    From Wordnik.com.  [Elements of Structural and Systematic Botany For High Schools and Elementary College Courses] Reference

The male plant has no definite stem, and consists of a single concave leaf protecting the antheridium.    From Wordnik.com.  [Encyclopaedia Britannica, 11th Edition, Volume 4, Part 3 "Brescia" to "Bulgaria"] Reference

The diameter of the antheridium now increases rapidly, and the central cells separate, leaving a large space within.    From Wordnik.com.  [Elements of Structural and Systematic Botany For High Schools and Elementary College Courses] Reference

These cells, especially the outer ones, develop a great amount of a red pigment, giving the antheridium its characteristic color.    From Wordnik.com.  [Elements of Structural and Systematic Botany For High Schools and Elementary College Courses] Reference

Both as regards the structure of the plant itself, as well as the reproductive organs, especially the very complex antheridium, the.    From Wordnik.com.  [Elements of Structural and Systematic Botany For High Schools and Elementary College Courses] Reference

They are discharged by the bursting of the antheridium, together with a mucilage formed of the degraded walls of their mother cells.    From Wordnik.com.  [Scientific American Supplement, No. 531, March 6, 1886] Reference

Frequently a smaller cell (antheridium), arising from a neighboring filament, and in close contact with the oögonium, may be detected.    From Wordnik.com.  [Elements of Structural and Systematic Botany For High Schools and Elementary College Courses] Reference

The other branch (antheridium) grows up in close contact with the archicarp, and like it is shut off by a partition from its filament.    From Wordnik.com.  [Elements of Structural and Systematic Botany For High Schools and Elementary College Courses] Reference

The antheridium undergoes no further change, but the archicarp soon divides into two cells, -- a small basal one and a larger upper cell.    From Wordnik.com.  [Elements of Structural and Systematic Botany For High Schools and Elementary College Courses] Reference

While this is in process of growth, peculiar oval capsules or sporangia (usually 2 to 5 in number) are formed in close proximity to the antheridium.    From Wordnik.com.  [Scientific American Supplement, No. 460, October 25, 1884] Reference

If a ripe antheridium is crushed in a drop of water, after lying a few minutes the spermatozoids will escape through small openings in the side of the cells.    From Wordnik.com.  [Elements of Structural and Systematic Botany For High Schools and Elementary College Courses] Reference

When ripe, if brought into water, the antheridium bursts at the top into a number of irregular lobes that curl back and allow the mass of sperm cells to escape.    From Wordnik.com.  [Elements of Structural and Systematic Botany For High Schools and Elementary College Courses] Reference

When ripe, the antheridium opens at the end and discharges the spermatozoids, which are, however, so very small as scarcely to be visible except with the strongest lenses.    From Wordnik.com.  [Elements of Structural and Systematic Botany For High Schools and Elementary College Courses] Reference

A second portion of the oogonial branch is cut off just below the oogonium and constitutes the antheridium.    From Wordnik.com.  [Transactions of the American Philosophical Society] Reference

When the fertilization tube is formed, most of the protoplasm and usually all of the nuclei of the antheridium pass into it.    From Wordnik.com.  [Transactions of the American Philosophical Society] Reference

A pair of pollen masses suspended from the glands at an angle of the antheridium, "&c.    From Wordnik.com.  [Mysteries of Bee-keeping Explained] Reference