223 
method comes within the range of their capacities. Captivated by 
the readiness with which the Linnean method of counting the organs 
of reproduction could be applied to the phenogams, it was not illo- 
gical to conclude that the same organs would afford equal assistance 
among the cryptogams: ez wno disce omnes was the motto; but the 
authors who so unhesitatingly adopted it seemed perfectly unaware of 
the existence of a stumbling-block at the very threshold of the’ 
inquiry. The sepals, petals, stamens and pistils, so patent, so readily 
countable in the pheenogams, were either non-existent or undis- 
covered throughout the whole of the cryptogams; and systematists, 
instead of appealing to these parts, appealed to what they supposed 
would answer the purpose equally well. Sepals and petals were not 
to be seen ; but botanists supposed their representatives to exist in 
the monotonously isomorphous gemmules which dot the back of a fern- 
leaf. These, as we all know, are associated in clusters; and these 
clusters are sometimes round, and sometimes linear; sometimes 
naked, sometimes covered by a portion of epidermis; sometimes dis- 
cal, sometimes marginal. On these differences a system was invented 
by Sir James Edward Smith; and with this system the students of 
ferns are generally satisfied at the present day.* A system which, 
leaving the mere surface, should enter more fully into the inner life of 
the plant is, therefore, day by day growing more requisite and a more 
indispensable desideratum, especially amongst those who perceived 
and were ready frankly to appreciate the brilliant light thrown on the 
study of phenogams by the observation, that in some the increment in 
bulk was occasioned by the formation of new substance in the centre 
of the stem, and in others by the formation of new substance on the 
circumference of the stem,—a simple observation truly, but one which 
caused the almost immediate division of phenogams into Endogens 
and Exxogens. ; 
This radical difference, so to speak, in a physiological character, 
can scarcely be confined to the phenogams; and, inquiry having 
been once diverted from its original channel into one so totally new 
and unlooked for, it was to be expected that an extended application 
of the principle would be attempted in other portions of the world of 
plants. This has been the case. 
* Tt is not worth while to go back to the pre-Linnean era of Botany, or we should 
find Sir J. E. Smith’s system of ferns proposed by Ray. 
