92 



BOTANY. 



it is a large air space, into which the chlorophyll-bearing cells 

 (cZ.) of the plant project (J). 



The sexual organs are often produced in these forms upon 

 special branches (G), or the antheridia may be sunk in discs 

 on the upper side of the stem (Z), an.). 



FIG. 57. Forms of liverworts. A, Riccia, natural size. S, Anthoceros 

 (horned liverwort), natural size. sp. sporogonia. C, Lumtlaria, natural 

 size, x, buds. Z>, giant .liverwort (Conocephalus), natural size. an. anthe- 

 ridial disc. E, small piece of the epidermis, showing the breathing pores, 

 x 2. F, common liverwort (Marchantia) , x 2. x, cups containing buds. G, 

 archegonial branch of common liverwort, natural size. H, two young buds 

 from the common liverwort, x 150. /, a full-grown bud, x 25. J, vertical 

 section through the body of Marchantia, cutting through a breathing pore (s), 

 x 50. K, surface view of a breathing pore, x 150. L, a leafy liverwort 

 (Jungermannia) . sp. sporogonium, x 2. 



Some forms, like Marchantia and Lunularia (Fig. 57, (7), 

 produce little cups (x) , circular in the first, semicircular in the 

 second, in which special buds (//, /) are formed that fall off 

 and produce new plants. 



The highest of the liverworts (Jungermanniacece) are, for 



