118 



PLANT STRUCTURES 



special development has been in connection with the 



sporogonium (Figs. 93, 101). 



This complex sporogonium (sporophyte) has a large 



bulbous foot imbedded in the simple thallus, while 



above there arises a long pod-like capsule. The com- 

 plex walls of this cap- 

 sule contain chlorophyll 

 and air pores, so that 

 the sporogonium is or- 

 ganized for chlorophyll 

 work. If the foot could 

 send absorbing processes 

 into the soil, this sporo- 

 phyte could live inde- 

 pendent of the gameto- 

 phyte. In opening to 

 discharge spores the pod- 

 like capsule splits down 

 into two valves. 



Another peculiarity 

 of the Anthoceros forms 

 is in connection with 

 the antheridia and arch- 

 egonia. These organs, 

 instead of growing out 

 free from the body of the 

 thallus, as in other Liv- 

 erworts, are imbedded in 

 it. The significance of 



this peculiarity lies in 

 the f act t ] iat j t j^ a c h ar _ 

 . 



acter which belongs to 

 the Pteridophytes. 



The chief direction of development of the three liv- 

 erwort lines may be summed up briefly as follows : The 

 Marchantia line has differentiated the structure of the 



FIG. 101. Anthoceros gracilis : A, several 

 gametophytes, on which sporogonia have 

 developed ; B, an enlarged sporogonium, 

 showing its elongated character and de- 

 hiscence by two valves leaving exposed 

 the slender columella on the surface o^ 

 which are the spores; C, D, E, F, ela- 

 ters of various forms ; G, spores. After 



