174 
From these and other similar examples we 
are justified in the inference that such 
highly organized types represent the culmi- 
nation of lines of ancestors which must 
have extended far back into the earlier geo- 
logical periods, a view which gains weight 
from recent researches. 
Among the ferns the Eusporangiateae are 
recognized as representing the primitive 
forms, and they constitute the starting 
‘point for two parallel lines of descent, one 
of which leads to the Leptosporangiateae 
and finally culminates in the Heterosporeae. 
Recent studies of Parka decipiens have 
shown that this hitherto problematical or- 
-ganism from the Devonian is unquestion- 
ably to be regarded as one of the hetero- 
sporous felicineze, possibly allied to Marsilia. 
The occurrence of this plant in the same 
horizon as that in which the Eusporan- 
giateae first appear, somewhat abundantly 
and in a high state of development, is of 
-great significance, since it points without 
question to the origin of the ferns at a very 
much earlier date, probably not later than 
Silurian time. 
In studying a new Taeniopterid fern from 
the Lower Coal Measures of the Carbonif- 
erous of Henry county, Missouri, Mr. D. 
White notes certain resemblances on the one 
hand to Alethopteris, and on the other to 
Taeniopteris, to which he assigns his plant 
under the name of TZ. missowriensis. Dis- 
cussing this plant in relation to other known 
forms of the Marattiaceae, he endeavors to 
construct a hypothetical relationship which 
shows a Megalopteris stock of the Lower 
Devonian, to give rise in the Middle 
Devonian to Neuropteris, Alethopteris and 
Megalopteris proper. ‘Thence through suc- 
cessive formations these three lines of de- 
-scent lead to Dictyopteris and Odontopteris, 
which culminate in the Permo-Carbonifer- 
ous, and to Danaeopteris, Lomatopteris, Olean- 
dridium, Taeniopteris, ete., which either 
culminate or have their origin in the 
SCLENCE. 
[N. S. Von, XIII. No. 318. 
Trias, while Angiopteris originates at this 
latter horizon and Danaea makes its first 
appearance in the Jurassic. ‘The hypothe- 
sis is a suggestive one, but as the fructifica- 
tion of these plants is wholly unknown, and . 
as we have no data derived from the inter- 
nal structure, while the relations exhibited 
are based entirely upon leaf characters, it is 
impossible to attach very great weight to it 
except as a possible starting point for fur- 
ther observations. 
Recent studies of modern HEquisetaceae 
and the various species of Calamites by 
Jeffrey, offer some very suggestive conclu- 
sions respecting the phylogeny of this most 
interesting group of plants now in the later 
stages of decline. Embryological studies 
show that similar structures in the pro- 
thalli, the absence of a basal cell from the 
archegonia and the epibasal origin of both 
root and shoot, serve to establish a definite 
connection between the Equisetaceae and 
the Homosporous Lycopods, a relation 
which is further justified by a comparison 
of the stem structure. He also shows that 
-the close agreement between the Equi- 
setaceae and the Sphenophyllaceae makes 
the latter the protostelic ancestors of the 
former. An acceptance of these conclu- 
sions would carry our knowledge of the 
phylum back to Lower Devonian time, and 
show that while the direct line of descent 
passes through the Sphenophyllaceae and 
Equisetaceae, the Calamites arose as a side 
line. 
The phylogeny of the Gymnosperms has 
for many years constituted a subject of the 
foremost importance and interest, and it 
has received the most careful consideration 
at the hands of both paleontologists and 
botanists. The deep interest which cen- 
tered so largely in the Cycadaceae, has 
within the last few years received addi- 
‘tional strength not only through the dis- 
-covery of those remarkable collections of 
‘Cycads from the Mesozoic, which Ward 
