Age 244 ; “ Ss frachiedl and a Plysolgiod Botany. - ‘ 
- Cryptogamia are again divided into four ‘groups or sub- _ 
oe VIZ. 
THALLOPHYTES or Leafless Cellular Cryptogatne mr 
Plants which have no leaves and no vascular tissue, but are 
constructed of cells only. There are, however, certain 
transitional forms which must not be overlooked between 
these and the leafy Cryptogams. To this sub-division be- 
long: 1, Ale ; 2, Fungi; and 3, Lichens. It is impossible 
to lay down accurate lines of demarcation between these ~ 
three classes ; but it may be stated broadly that Algze con- 
tain chlorophyll, and are therefore able to avail themselves 
of inorganic food-materials ; while Fungi contain no chloro- 
phyll, and are therefore not able to make use of absorbed 
unassimilated food-materials, but are compelled to live as 
parasites on other organisms, or on organic remains. 
Lichens, again, assume an intermediate position, uniting in 
themselves the characters of Algee and Fungi. 
CHARALES. Submerged water-plants readily recog- 
nised externally by their organs of reproduction, which re- — 
semble a spirally striated nucule surmounted by a coronet. 
Their distinguishing characteristic lies in the peculiar pheno- 
mena connected with the formation of the organs of reproduc- 
tion (Figs. 418-420, pp. 292, 293). | 
3. MuscinEz. We have here a distinctly marked allies 
nation of generations. From the spore 1s developed either _ 
directly (in most Hepaticae) or indirectly, as the lateral 
branch of a so-called fro-embryo (in some Hepaticee and 
all Musci) a plant which bears the organs of reproduction; 
this is the first [sexual] generation. The result of fertilisation 
is the second [nonsexual] generation, a fruit-like structure, 
the sporogonium, in which the spores are formed. This ~ 
group is divided into two classes: 1, Hepatice, and 2, 
Musci, of which the former has capsular sporogonia, usually — 
opening with valves, and containing, in addition to the — 
spores, eaters, i.e. elongated spirally thickened cells (Fig. 422, _ 
Ill. p. 295) [the object of which 1s to assist the disseminas a 
/ 
