Comparative Anatomy of the Casuarineae . 253 
elongated, fibrous elements with granular contents and starch, 
which Sanio 1 mentioned long ago under the name of ‘ Libri- 
formzellen 5 as constituting one of the chief differences between 
the anatomy of this plant and that of the Coniferae ; they 
are probably formed from cambium-segments which, after 
being cut off, undergo no transverse division whatever. The 
cambium-cells themselves appeared to be of great length. 
These elements are analogous to those in Gnetum (described 
above). 
The phloem is much the same as in Gnetum ; the elements 
composing it are approximately of the same diameter. The 
sieve-tubes have very oblique terminal walls with compound 
sieve-plates, these latter also occurring on the lateral radial 
walls. The albuminous cells adjoining the sieve-tubes have 
dense contents with large and long nuclei, some of which 
appear curiously constricted in the middle. There are very 
numerous brown fibres in the cortex. 
The anatomy of the node of Ephedra is very different in 
many respects from that of the internode. On looking at 
either a transverse or a longitudinal section of this part of the 
stem, one is at once struck with the uniformity of the structure, 
all the elements being approximately of the same size ; the 
characteristic vessels of the internode are entirely absent, and 
the tracheal tissue consists entirely of tracheides ; in fact, the 
wood here resembles very much that of Taxus or some other 
Taxaceous genus, owing to the complete absence both of the 
vessels and of the wider tracheides. Another peculiarity of 
this part of the stem lies in the striate appearance of most of 
the tracheides ; these striae, which usually form a double 
spiral round the element, are very faint, and in no way com- 
parable to the tertiary spirals seen in Taxus , Casuarina , &c. ; 
in many cases it was plainly seen that this appearance was 
due to a regular splitting of the wall, as the faint lines were 
continuous with the slit-like openings of the bordered pits, 
and formed often quite wide slits at these points. In other 
Loc. cit., 1863, p. 406. 
