CURREY, ON THE HIGHER CRYPTOGAMIA. 69 
of the conversion of the germinating spore into a single row of cells, one 
of which cells, by repeated divisions in all three directions of space, be- 
comes the rudiment of the leafy axis. This phenomenon is as well 
marked as in any of the mosses. The outward form of the antheridia 
and archegonia in the two groups differs very slightly. The first stages 
of development of the fruit-rudiment of the mosses on the one hand and 
the Jungermanniz on the other, are, it is true, very different. In the 
former the longitudinal growth is caused by the continually repeated 
division of a single conical apical cell of the organ, by means of septa 
inclined alternately in two directions; in the latter this growth is caused 
by the repeated division by horizontal septa, of four cells constituting the 
upper end of the fruit-rudiment. But the normal mode of cell-multipli- 
cation in the fruit-rudiment of the Marchantiee (including the Tar- 
gioniez), and of the Ricciew, coincides exactly with that of the mosses. 
Lastly, Anthoceros exhibits a form of cell-multiplication of the endo- 
gonium which is the same as that of the punctum vegetationis of the ends 
of the axes of a great number (probably the majority) of phenogams. 
The septa produced in the one apical cell of the organ, are inclined in 
regular succession towards the four points of the compass. The presence 
or absence of a columella, or of elaters in the ripe fruit, are points of no 
characteristic value; Anthoceros has the columella, but this genus and 
the Ricciez have no elaters. Radula in the Jungermanniez has a vagi- 
nula, and so has Anthoceros. 
Upon instituting a closer comparison between the mode of develop- 
ment of different forms, four types soon become conspicuous, around 
which all the phenomena hitherto sufliciently investigated may be con- 
veniently arranged. We thus arrive at the following equivalent groups, 
which are not however equally rich in the number of genera and forms. 
1. Mosses according to the ordinary limits of the family, including the 
Sphagnacee. 
2. Jungermanniezx; in which the leafy ones are connected with the 
leafless ones by a succession of intermediate stages. 
3. Marchantier, Targioniex, and Riccier; all intimately connected 
with one another by the similarity of the earliest conditions of the fruit, 
as well as by many vegetative phenomena,* 
4. Anthocerotes. 
The mode in which the second generation originates from the first is 
much more various in the vascular cryptogams than in the others. All 
ferns however agree in the fact that the first axis of their embryo has only 
a very limited longitudinal development ; it is an axis of the second order 
which breaks through the prothallium and becomes the principal axis ; 
and they all agree further in this, that the end of the axis of the first 
order never forms the root. All vascular cryptogams are without main 
roots; they have only adventitious ones. 
In more than one respect the formation of the embryo of the Conifer 
is intermediate between the higher crytogams and the phenogams. Like 
the primary mother-cell of the spores of the Rhizocarpex and Sellaginella 
the embryo-sac is one of the axile cells of the shoot, which in the one case 
becomes converted into the sporangium, in the other into the ovule. In 
the Conifers also the embryo-sac soon becomes free from any mechanical 
connexion with the surrounding cellular tissue. The filling of the 
embryo-sac by the endosperm may be compared with the production of 
* As, for instance, the precisely similar succession of the shoots; the 
separation of the tissue of the shoots into an upper layer with intercellu- 
lar cavities, and a lower layer without cavities; the occurrence of pecu- 
liar thickenings upon the inner wall of the capillary roots, &c. 
