able from the nein: material, seems bi indicate that these 
“another; but in the present unsatisfac oe 
_ material now available, no final conclusion can be drawn. From ene 
the evidence at hand, however, it would : seem that the —— ele ~ = 
‘postion of the sclerenchym na: 
1897 | MYELOPTERIS TOPEKENSIS 19 
sides by rows of thick walled fibrous elements. The phloem, 
rather small in volume, is here much broken down, but it is 
situated radially outward, while in the other bundle (jig. 7), 
where it is rather more perfectly preserved, it is situated radially 
inward. The protoxylem is here seen as a group of smaller 
elements much altered by compression (fig. ¢), or in other 
instances more perfectly preserved (fig. 7), sometimes on the 
outer face of the vessels, and sometimes on the inner face, but 
always between them and the phloem. While the bundles vary 
considerably in size, they all conform to the collateral type and 
it is of interest to note that in all their structural features, they 
agree very closely with the bundles of a species of Myeloxylon 
described by Solms-Laubach,’ and also by Seward.° 
From the present material I have been wholly unable to 
obtain satisfactory details of the structure of the bundle in 
longitudinal section, beyond the fact that the vessels are dis- 
tinctly scalariform, and in this respect they conform to the type 
generally observed in ferns. 
The peculiar situation of these bundles is not altogether easy 
to account for. They certainly appear to lie between, and are 
therefore mingled with, the strands of sclerenchyma, from which 
circumstance I was at first led to suppose them to be collateral, 
as in the case of Phoenix and other palms, but a very careful 
examination fails to disclose any satisfactory evidence of such 
relationship, while in some cases at least the vascular bundle is _ 
separated from the nearest sclerenchyma strand by a broad zone 
of fundamental tissue. Indeed, the evidence, so far as obtain-— 
Bae ib one 
les and th 
| 26 ory ‘condition of. ‘the a 
me oe nor ra 
bundles have their extreme outward : 
: “From this 
Vien 161, fg. 1B. 
ieee Bot. 7 pl.T and Z/, j 
