338 



PRACTICAL COURSE IN BOTANY 



upper part, the neck, which is perforated by the neck canal, 

 ca. The venter contains the egg cell, o, and the ventral canal 

 cell, vc. The neck canal is filled with small cells which, 

 at maturity, dissolve into a mucilaginous substance that 

 swells on being wet and discharges itself through the top 

 of the neck, leaving an open passage to the venter, where 

 the egg cell is ready to be ferti- 

 lized. 



Make a drawing of the section as 

 seen under the microscope, labeling 

 all the parts. 



392. Fertilization. — In the liver- 

 worts, and in cryptogams generally, 

 this process has to take place under 

 water, as the antherozoids are motile 

 only in a liquid, but the amount re- 

 quired is so small that a few drops 

 of rain or dew will enable them to 

 make their journey to the archego- 

 nium. The mucilaginous substances 

 discharged from the neck canal at- 

 tract them to the mouth of the open- 

 FiGs. 480, 481.— 480, young iug, ouc or more of them penetrates 



archegonium of M polymor- ^ ^j^ ^ j^ ^^^ fertilization is aC- 



pha ; V, ventral portion ; o, egg _ °=' ' 



cell ; vc, ventral canal and cells ; COmplished. Do yOU SCe any aual- 



ca, neck canal with cells; 481, • 1 1 it • 1 ±1 



the same ready for fertilization Ogl^S bctween thlS and the Same 



after discharge of the mucilagi- function amOUg floWCring plauts? 



nous fluid. /^_^ ^^^ s 



(250, 251.) 

 393 . The spore case. — After fertilization the egg becomes 

 an oospore, capable of producing a new plant. Instead, 

 however, of separating from the mother plant and giving 

 rise to an independent growth, it germinates within the ar- 

 chegonium and produces there a small, stalked body, called 

 a sporogonium, or sporophyte, which at length ripens into 

 a spore case, as shown at /, Fig. 479. At maturity this 

 capsule-like sporophyte ruptures at the apex, and discharges 



