214 DR. D. H. SCOTT : 
The Halle specimen under the name C. annularis (Solms, 420) is remark- 
able for two features—the narrowness of the medullary rays and the 
smallness of the pith. The specimen (Phot. 19) includes the whole of the 
latter and a large portion of the wood, but probably not its full thickness, 
The present radius is about 14 mm. 
The pith, including the primary xylem, only measures about 2:5 x L7 mm. 
(Phots. 19, 20). No stems of C. annularis with a small pith like this are 
mentioned by Solms-Laubach, so presumably this specimen only came under 
observation after his paper was published. The question arises, is it rightly 
named Calamopitys annularis? The primary xylem forms an irregular zone 
in which some of the strands are fairly well defined, but appear to be con- 
nected by intermediate tracheides. At some places the xylem forms a 
continuous band, while elsewhere there are only scattered tracheides between 
the primary strands; this difference may simply be due to unequal pre- 
servation, It is extremely difficult to make out any protoxylem in the 
primary strands; where elements smaller than the rest occur, they lie 
towards the outer edge of the strand (Phot. 20). 
The pith is badly preserved ; a certain number of largish elements, with 
somewhat thick walls and clear lumina, persist and suggest tracheides 
(Phor. 20). The radial section confirms this suggestion. This section 
extends right across the pith, which contains many long tubes, agreeing in 
appearance and size with the tracheides of the primary wood. In the case 
of a stem with so small a pith one cannot be certain that the section, though 
apparently radial, may not be sufficiently tangential to the pith to pass 
through the inner part of the xylem-ring, However, it is probable that some 
of the more scattered tubes really represent medullary tracheides. 
The secondary wood is remarkable, for it nowhere shows the wide 
medullary rays characteristic of the species. Most of the rays seen in trans- 
verse section are uniseriate; about half as many are biseriate ; larger 
numbers (locally four rows of cells were seen in a single case) are extremely 
rare. There is no tangential section of the specimen, but one may con- 
jecture that the ray in this form commonly hada middle portion two rows 
wide, with a uniseriate extension above and below. The whole appearance 
of the wood is very different from that of the typical C. annularis 
(cf. Phots. 12, 18). The rays are also very narrow in actual dimensions, the 
single ray-cell being commonly about 12 w wide. 
The secondary tracheides are small; a rough average giving about 36 u 
for the diameter. Consequently the radial section shows few rows of pits on 
the wall; usually they are in 1-3 rows, rarely 4. Otherwise they appear 
to agree with the pits of the first specimen. 
The Halle stem is obviously different in certain points from the typical 
form of the species. It is certainly not C. Saturni, for, as will be seen 
presently, a specimen of that plant of about the same dimensions as regards 
