348 PHARMACEUTICAL BOTANY 
asexual or sexual. Asexual reproduction is accomplished by 
means of tuber-like bodies borne on submerged parts or by 
special branches which form rhizoids on their lower nodes and 
later become separated from the parent plant. Sexual reproduc- 
tion is effected through the formation of odgonia (female sex 
organs) and antheridia (male sex organs). These in some species 
are borne on the same plant; in others, on different plants. In 
all cases the sexual organs are 
produced at the nodes of dwarf 
branches. The oval oégonium is 
borne above the spherical anther- 
idium. The oégonium develops 
within itself a large ovum or egg. 
The antheridium produces within 
its wall numerous motile sperms. 
Upon the maturation of the an- 
theridium the sperms are liberated 
into the water, and, propelled by 
iS their cilia, find their way to the 
Fic. 252.—A, Portion of the axis of °0§0nia which they enter, the one 
Chara fragilis, a stonewort. s. Oogoni- best adapted fusing with the egg 
um (one-celled female sexual organ). in each case and’ fertilizing it. 
Abortive “leans” Br ie oom The resultant cell is called the 
“leaves.” c. Crown ofodgonium, B. 00Spore or zygote. The zygote 
Young stage of the same. r. Corti- undergoes a resting stage within 
Se sts 6. Antberiiien, sh Oligo 1h. odgonium. The odgonium 
nium. (From Small, after Sachs.) z 
with the enclosed zygote falls from 
the plant and sinks to the bottom of the water. The zygote later 
germinates as a proembryo or juvenile form of Chara plant. The 
proembryo consists of a small shoot of two nodes and a long 
rhizoid. From the upper node of this proembryo, the adult form 
of Chara arises as a side shoot, and from the lower node rhizoids 
are formed. 
Crass ITI.—BacitLariE& or DIAToms 
This class comprises several thousand species of unicellular 
plants called Diatoms which are found in fresh, brackish and salt 
water, forming much of the diet of small animals. While 
