HEPATIC^E. 



[ 388 ] 



HEPATIC^E. 



receptacles (see MARCHANTIA) ; in the leafy 

 forma they are free in the axils of the 

 leaves (fig. 323). 



Fig. 322. 



Fig. 323. 



Fig. 324. 



Haplomitrium Hookeri. 



Fig. 322. Axillary antheridia. Magn. 30 diams. 



Fig. 323. Fragment of wall of antheridia ; the reni- 

 form loose cells belong to the inner layer. Magn. 200 

 diams. 



Fig. 324. Spermatozoids from ditto. Magn. 200 diams. 



Fig. 325. Fig. 326. Fig. 327. 



Marchantia polymorpha. 



Archegonia in various stages. 



Magnified 100 diameters. 



The arcfagonia or pistillidia are likewise 

 developed in various places, indicated here- 

 after in the tabular view of the families. 

 They consist of a kind of flask-shaped cellu- 

 lar case (figs. 325 to 827), enclosing at first 

 a single cell (embryonal cell), which subse- 

 quently grows into a sporange, apparently 

 after one or more of the spiral filaments of 

 the antherids have come in contact with it, 

 by passing into the neck of the flask-shaped 

 sac (epigone}. The embryonal cell becomes 



increased by cell-division into a globular 

 cellular mass, which acquires various forms 

 in the different genera and families. The 

 epigone enlarges for a long time with the 

 growing capsule, completely enclosing it 

 (fig. 328) ; but after a time the latter bursts 



Fig. 328. 



Haplomitrium Hookeri. 



Young sporange enclosed in the epigone. 



Magnified 20 diameters. 



through the top of the epigone, which thus 

 forms a kind of sheath round the base of the 

 sporange or its stalk, and is called the vagi- 

 nule. The epigone may tear irregularly, so 

 as to form an irregular vaginule or calyx, or 

 regularly, so as to present a circle of teeth ; 

 or it may be slit horizontally in a circle, and 

 half of it carried up by the sporange, which 

 it thus surmounts as a hood or calyptra. 

 This epigone is sometimes surrounded by 

 another envelope called the perigone. This 

 originates at a later period and in a different 

 way, since it gradually springs up as a cir- 

 cular sheath around the base of the epigone, 

 and by continued growth comes to surround 

 it as a kind of cup, like the corolla of a 

 flower (fig. 320). In Marchantia, only one 

 archegone is found in each perigone; the 

 perigones of Juugermannieae always enclose 

 several, but only one is developed into a 

 sporange. In some kinds, as Sarcoscyphus, 

 there are always several archegones in a 

 perigone, and two or three produce spo- 

 ranges. Sometimes the archegones, with or 

 without perigones, are solitary; more fre- 

 quently they are in groups. Whether soli- 

 tary or grouped, they may have a further 

 envelope composed of slightly modified 

 leaves, free or confluent together ; these are 

 the perichcetial leaves, and constitute the 

 perichcete. When both perichcete and peri- 

 gone exist, it is easy to determine which is 

 which; but when only one exists, the history 

 of development alone gives the key; the 



