1915] BURLINGAME—ARAUCARIANS 21 
case, the cones of the two resemble one another closely in apparent 
structure, and will probably both be eventually satisfactorily 
explained in the same way. 
The seed of Araucaria resembles that of Cordaites in having the 
nucellus free from the integument to a zone below the female 
gametophyte. It is doubtful whether this is a character of any 
great consequence, inasmuch as there were seeds of both types 
known among paleozoic plants. Nevertheless, it remains true that 
this ancient type is not known in any other modern plants. Cor- 
daitean seeds, so far as yet definitely known, appear to have had 
pollen chambers in the nucellus. Since the pollen has been found 
in these chambers, in some cases apparently sealed in, one can only 
infer that the method of pollination was essentially the same as 
that of modern Abietineae. In this respect the Araucarineae 
differ very markedly. To the writer the difference appears so 
great, and the method of the Cordaitales so much superior, that it 
is difficult to believe that having been once attained it would ever 
have been given up (36). If there is any dependence to be placed 
on the facts that appear to indicate that podocarps have been 
derived from an araucarian ancestry, it would appear that the 
tendency of evolutionary selection had been in this case in the other 
direction. This objection does not appear to be very formidable 
at present, for we know many more seed genera from impressions 
than we have plants to assign them to. Moreover, we know the 
internal structure of very few of them. It is not unreasonable to 
Suppose that the Cordaitales may have borne more than one sort 
of seed, and that among them may have been some which were 
pollinated in the araucarian fashion. 
When the pollen cones are considered, it is at once evident that 
the closest resemblances to those of the Cordaitales are found in 
three rather widely unrelated groups: Ginkgo, araucarians, and 
taxads. Doubtless they have all inherited their resemblances from 
a common source, though along little related lines. So far as the 
evidence goes, it constitutes a notable resemblance between the 
araucarians and cordaiteans, in which the abietineans do not share. 
The araucarian type, with its free pendent sporangia, has apparently 
been transformed into the more common conifer type with two 
