368 On the Genealogy of Plants. [June, 
That the Conifere proper (Adietinee) have descended from the 
second or club-moss group, seems even better established than 
that the Cycads have sprung from the ferns. 
The affinities of the extinct Lepidodendron with this group have 
always been recognized. Those who claim for Lepidodendron a 
Coniferous character only strengthen this view by showing how 
closely the two groups approached each other in those ancient 
times. The Araucarian pine of the southern hemisphere is even 
now covered with scales over its entire surface, and presents no 
small analogy with the Lycopodiacee and with what is known to 
have been the character of Lepidodendron. We must, therefore, 
regard Araucaria as our nearest living representative of the early 
transition form through which the Pine family was derived from 
the Carboniferous Lepidophytes. And it is especially interesting 
to remark that it is just this Araucarian group of true Conifers 
which we find associated with the arborescent cryptogamic vegeta- 
tion, and whose scaly trunks lie side by side with the equally 
scaly trunks of Lepidodendron in the coal formation—a fact which 
shows at how early a period the differentiation began, and how 
little progress has been made within the same group during sub- 
sequent geologic ages. 
With regard to the great advance which must have been made 
in passing from the crytogamic to the gymnospermous reproduc- 
tive system, the evidence has already been briefly referred to. To 
the Rhizocarpee in the fern group correspond the Ligu/ate in the 
club-moss group, in which the asexual spore is completely differ- 
entiated into the sexual macrospore and microspore. In this 
order the only two genera thus far known, /soétes and Selaginella, 
have been faithfully studied by the foremost botanists of Europe, 
and the facts repeatedly verified. Hoffmeister’s generalization, 
which is of the highest importance and has been generally 
accepted, has already been adduced, and its direct bearing on the 
immediate question need scarcely be reaffirmed. 
The origin of the Gnetacee is far more obscure, and indeed so 
few positive facts have been brought forward to establish it that 
- all speculation may be pronounced idle. That there is conside: z 
able general resemblance between the genus Æphedra and cadens 
branching species of Eguisetwm, cannot be denied, but this simi- 
larity of habit is not accompanied by any corresponding similarity 
of structure either in the tissue or in the fruiting apparatus, while 
pee 
Fie, 
Ra Eee ow ee 
