HORNWORTS 245 
(the sporophyte), whose interior cells divide into spores, 
but there are no “elaters.”” Although still surrounded by 
the distended archegone this sporophyte is not organically 
connected with any part of the gametophyte. The spores 
escape by the decay of the surrounding layers of cells, and 
on germination give rise to gametophytes like that with 
which we started. ; 
428. In the Hornworts (Anthoceros) the gametophyte 
is a thin thallus of somewhat more compact tissue than 
in Riccia, and growing on moist earth. The antherids 
Fie. 118.—Riccia. - Fie. 119.—Anthoceros. 
and archegones are sunken in the upper surface, and 
resemble those of Riccia. When fertilized the egg de- 
velops into an elongated, cylindrical sporophyte whose 
upper part emerges from the neck of the archegone, 
while the enlarged base remains seated in the venter. 
The sporophyte is made up of a considerable mass of 
green tissue, and is surrounded by an epidermis which is 
supplied with stomata like those of higher plants. This 
the first appearance of true stomata in the Vegetable 
Kingdom. 
429. The lower part of the sporophyte continues to 
grow in length indefinitely. Internally there is a layer 
of cells by the division of which spores are formed, and 
intermingled with these spores are the elongated sterile 
cells called ‘‘elaters.’’ As the spores ripen above the 
sporophyte splits from the top to permit their escape. 
