364 



But in Figure 357 showing a similar branch all three cells are seen. 

 From these three cells the pericarp originates, in fig. 356 each of 

 the two cells seen have already produced a single cell each. 



Quite independently and separated from the auxiliary branch- 

 system the carpogonial branches are developed. These are formed 

 in much greater number than the auxiliary branches. In the part of 

 the tissue shown in the Fig. 356 six are to be seen. The carpogonial 

 branches are borne either from the large cells of the peripheral tissue 



or from the filaments 

 found here. It consists 

 of a variable number of 

 cells, about two to four 

 or sometimes five cells. 

 The trichogyne is long, 

 mostly screw-formed 

 with a thickened sum- 

 mit; in penetrating the 

 peripheral tissue it be- 

 comes thinner. In the 

 figure the trichogynes 

 of the carpogonial 

 branch to the left and 

 those of the carpogon- 

 ial branches nearest to 

 the right of the auxiliary branch have penetrated the peri- 

 pheral tissue to become fertilized. After the fertilization the 

 trichogyne gradually dies away, but at the same time the con- 

 jugating tube begins to grow out from the carpogone. The grow- 

 ing-out of this tube is seen in the carpogonial branch found close above 

 the auxiliary branch in Fig. 356. Sometimes two or even three of those 

 conjugating tubes are developed from the carpogone. These tubes 

 are mostly very thin and may reach a considerable length; they pro- 

 trude freely everywhere in the cavity of the thallus, until one of them 

 succeeds in reaching an auxiliary cell. Then the summit of the tube 

 becomes thicker and closely connected with it merging together with 

 it. This process seems always to take place at the basal end of the 

 auxiliary cell. Fig. 357 shows this stade of the fertilization; in this 

 ease the conjugating tube is issued from a carpogonial branch just 



Fig. 357. Agardhiella tenera (J. Ag.) Schmitz. 



The process of fertilization. 



(About 350:1). 



