68 CURREY, ON THE HIGHER CRYPTOGAMIA. 
lar body is produced which in the mosses forms the rudiment of the fruit, 
and in the vascular cryptogams, the embryo. The object of the second 
generation is to form numerous free reproductive cells—the spores—by 
the germination of which the first generation is reproduced. The leafy 
plant in the mosses answers therefore to the prothallium of the vascular 
cryptogams ; the fruit in the mosses answers to the fern in the common 
sense of the word, with its fronds and sporangia. The pro-embryo, that 
is to say the confervoid process produced by the germinating spore of 
most of the mosses and many of the liverworts, cannot be looked upon as 
a special generation any more than the similar organ (the suspensor) in 
phenogams. It isto be remembered that when new individuals are produced 
from single cells of the leaf of a moss, and also during the development 
of the gemme of many mosses, the formation of the rudiment of the 
first leafy axis is preceded by the formation of a similar confervoid pro- 
embryo. This holds good as well in the mosses* as in those liverworts 
which possess a pro-embryo. When new individuals are formed from 
the fragment of a leaf of Lophocolea heterophylla or of Radula compla- 
nata, the cell of the surface of the leaf which becomes the mother-cell of 
the new plant produces in the former of the above-named plants a single 
or double row of cells, and in the latter a cellular surface. In each case 
the body produced is exactly similar to the pro-embryo which originates 
from the germinating spore in both species. 
The vegetative life of the mosses is confined exclusively to the first, 
and the fructification to the second generation. The leafy stem alone 
sends forth roots: the spore-forming generation draws its nourishment 
from the first generation. The life of the fruit is usually much shorter 
than that of the leaf-bearing plant. In the vascular cryptogams this 
state of circumstances is reversed. It is true that the prothallia send out 
capillary roots: this is always the case in the Polypodiacez and Equise-~ 
tacez, and frequently in the Rhizocarpez and Selaginellz. But the pro- 
thallium lives a much shorter time than the leaf-bearing plant, which 
latter, in most cases, does not produce fruit for several years. The con- 
trast, however, is not so marked as it appears at first sight. The appa- 
rently unlimited life of the leaf-bearing moss depends merely upon con- 
tinual renovation. Phenomena of a similar kind are met with in the 
sprouting prothallia of Polypodiaces and Equisetacee. In the lowest 
liverworts (Anthoceros and Pellia) the structure of the fertile shoots 
is less complicated, and their duration little longer, than that of the 
fruit. On the other hand the ramification of the prothallium of the 
Equisetacez is very variable ; its life is not of shorter duration than that 
of an individual shoot. 
It is a circumstance worthy of notice that in the second or spore-form- 
ing generation of mosses and ferns, complicated thickenings of the cell- 
walls usually occur (witness the teeth of the peristome in mosses, the 
capsule-wall and the elaters in liverworts, and the vessels in ferns), whilst 
in the first generation these thickenings are rare and exceptional. 
An unprejudiced consideration of the subject will show that the sepa- 
ration into two groups only of the plants comprising the mosses on the 
one hand, and the liverworts (Jungermanniex, Marchantiex, Anthoce- 
rote, and Ricciee) on the other, is not natural. There is no marked 
feature by which these two groups can be distinguished. It is true that 
a pro-embryo like that in the mosses is wanting in most of the genera of 
liverworts, especially in all the leafless ones. Many leafy Jungermah- 
niew, however, especially the true Jungermanniz, exhibit the phenomenon 
* W. P. Schimper’s excellent work, ‘Recherches sur les mousses,’ 
renders it unnecessary for me to cite examples. 
