348 The Botanical Gazette. [September, — 
With no desire, however, to overestimate its importance, 
I wish to place before you the position in the botanical sys- 
tem of a comparatively obscure group of plants and to call 
your attention for a brief time no less to their own differen- 
tiation than to their important relation to the evolution of © 
the plant world. I desire to set forth in something of a rea- 
sonable way the characters of the group and to correct some 
misunderstandings that have resulted from an imperfect appre- 
ciation of its relations. The group commonly known as He- 
tive of this triply developed group of plants, notwiths 
the fact that the other members of this trio are vastly a 
important—one in the nature and extent of its devine 
per se, and the other in its important relations to the oun 
opment of the higher groups of the plant world. ere 
mentary text-book that has in general done much to @") 
the standard of botanical teaching in America ee 
: atice / 
past decade opens its account of the Hep the most 
words: ‘In the liverworts the plant body is fo 
part either a true thallus or a thalloid structure. This 
there is a differentiation into stem and leaves, o ncepti 
statement may be taken as fairly representing 4 | aoe 
of the group common among botanists and bola ; 
The hepatics among us are popularly supposed t0 ?¢ 
or thalloid plants and Marchantia is regarde 
representative. As opposed to this wide-sprea 
tion, it should be noted that as far back ast tice (1847) 
last publication of a general synopsis of the Hepa 
the relative numerical importance of the Marc 
only 17 per cent. of the entire group and 
that time has been even more largely in t 
other groups, especially the foliaceous Junger™ 
represent at once the most numerous and best 
he direction 
aniace® ™ 
aye one 
the increase of the 
which 
differentia” 
