HEPATIC^. 



[ 388 ] 



HEPATIC-E. 



receptacles (see Mabchantia) ; iu fhe leafy 

 forms they are free in the axils of the 

 leaves (fig. 323). 



Fig. 322. 



Fig. 323. 



Fig. 324. 



Haplomilrium Hookeri. 



Fig. 322. Axillary antheridia. INIagn. 30 diams. 



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

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

 diams. 



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



Fig-. 325. 



Fio-. 327. 



Marchantia polymorpha. 



Archegonia in yarious stages. 



Magnified 100 diameters. 



The archegonia or i^^^tilUclia are likewise 

 developed in various places, indicated liere- 

 after in th(3 tabular view of tlie lauiilies. 

 They consist of a kind of tlask-sliaped cellu- 

 lar case (figs. 320 to 327), enclosinir at first 

 a single cell {e^nhryonnl cell), which subse- 

 quently grows into a sporange, apparently 

 after one or more of tlie spiral filaments of 

 the antherids have come in contact with it, 

 hy passing into the neck of the fiask-shaped 

 sac {epiyone). The emhr^-onid cell becomes 



increased by cell-division into a globular 

 cellidar 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. 



HaplomitriuDi Hookeri. 



Young sporange enclosed in the epigone. 



Magnified 20 diameters. 



through the top of the epu/one, which thus 

 forms a kind of sheath rouud the base of the 

 sporange or its stalk, and is called the vagi- 

 nule. The epigone may tear irregularly, so 

 as to form an irregidar vagmide or cah/x, or 

 regularly, so as to present a circle of teeth ; 

 or it maj' be slit horizontally in a circle, and 

 half of it carried up by the sporange, which 

 it thus surmounts as a hood or cah/ptra. 

 This epigone is sometimes surrounded by 

 another envelope called the j^'^i'tgone. This 

 originates at a later period and in a diflferent 

 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 Jungermannieae always enclose 

 several, but only one is developed into a 

 sporange. In some kinds, as Sarcoscgphits, 

 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, thej' may have a further 

 envelope composed of slightly modified 

 leaves, free or confiuent together : these are 

 the perich<^tial leaves, and constitute the 

 perichcete. When both pericha-ie 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 j the 



