THE TWO GENERATIONS 411 
foot extends into the gametophore and absorbs food which is 
supplied to the elongating stalk and developing sporangium. 
In the sporangium are produced numerous spores and also 
elongated twisted cells called elaters, which assist in scattering 
the spores. When the spores are 
mature the sporangial wall opens 
and the spores are scattered. When 
the spores fall on a moist substra- 
tum, they germinate and produce 
new thallus plants like the ones 
described. 
The Two Generations. — The ob- 
long body produced by the fertilized 
egg, and consisting of foot, stalk, 
and sporangium, is regarded as a 
plant within itself. When fully  p. s66.— Highly mnethed 
mature it is so small that one must vertical section through the 
look closely under the finger-like expanded top or conceptacle of 
lobes to find it. It doesn’t look a male gametophore, showing 
much like a plant, since it is so the antheridia (a) imbedded in 
: the gametophore and consist- 
simple and depends upon the ing of a short stalk and of a 
gametophore for food and water, jacket enclosing numerous cells 
but it is this plant that differenti- which form sperms. 
ates and becomes the conspicuous 
plant body of the higher plants. Since it produces spores, it 
is called a spore plant or sporophyte. When one is reminded 
that a Corn plant or Apple tree is all sporophyte excepting some 
microscopical structures within the flowers, then the significance 
of this small sporophyte of the Liverworts in relation to the 
origin of the higher plants may be realized. 
It is obvious that if this little sporophyte is regarded as a plant, 
then all of the remainder of Marchantia must be regarded as 
another plant. This other plant consists of all that has been 
described as the plant body of Marchantia. It consists of the 
flat prostrate thallus and the gametophores with the sex organs 
and gametes. Since it is the function of this plant to bear 
gametes, it is called gametophyte. 
It follows then that the complete life cycle of Marchantia in- 
volves two plants or generations as illustrated in Figure 367. 
The gametophyte generation develops from a spore and produces 
