342 Barber . — Ciipressinoxylon veciense . 
that the specimens are smaller branches and roots, an 
assumption which is supported by a number of other 
characters, although a few difficulties are met with. 
It should be pointed out in passing that this distinction 
between root- and stem-structure must be used with a certain 
amount of caution. If, as Mohl holds, it has its explanation 
in fundamental differences in the function of the two organs, 
it will be capable of wide application h There are, however, 
instances of stems exhibiting the typical root-arrangement. 
Thus Strasburger, in describing the last- formed layers of 
an old moribund Larch, states that the stem-rings are small 
and consist of very wide spring-tracheides followed suddenly 
by narrow thick-walled summer-cells. The same arrange- 
ment was found in the wide rings of a perfectly healthy 
Larch forty-eight years old. It is indeed stated by Nord- 
linger to be a common feature of Larch-wood 1 2 . Lastly, Mold 
expressly remarks on the small difference between the outer 
stem- and root-rings of the Larch. It cannot then be con- 
sidered altogether safe to use this character alone in deter- 
mining the root- or stem-nature of fossil woods. To give an 
example, Cupressinoxylon distichum , described by Mercklin 8 , 
is now regarded as a root, and yet the rings (which are stated 
to be the outer rings of a very thick trunk) correspond exactly 
with those of Strasburger’s old dying Larch stem 4 . 
In one of the specimens the rings are wavy, i. e. thrown 
into a series of irregular arches around the section (Fig. i). 
This has been noted as an occasional occurrence in many 
recent Coniferae ; and among fossils in Citpressinoxylon 
nodosum (root) by Goppert 5 and C. erraticum Terebinum and 
C. Fritscheanum by Mercklin 3 . The arches render the 
measurement of the elements difficult, since the cells are 
much smaller where two arches meet, as if these regions 
were subject to pressure. Possibly this is due to the nearness 
1 Mohl, 1. c. 2 Strasburger, 1. c., p. 24. 3 Mercklin, 1. c. 
4 See also Kobbe, Ueber die fossilen Holzer der Mecklenburger Braunkohle, 
Inaug. Diss., Rostock, 1887. 
5 Goppert, Monograph. 
