compared with other genera of Cycadeae . 609 
the fact that in none of the rings could I detect any callus- 
formation seems to point to the conclusion that the growth 
of the stem as a whole had been arrested ; this seems the 
more probable from the fact that the whole organ was 
infested in every part, from apex to base, with the mycelium 
of a Fungus, a condition of things which might tend to 
materially affect the normal functions of the stem. Indeed, 
the reason why this stem had been handed over to the 
Laboratory was that the apex was in a state of decay, and 
the plant had therefore become worthless for purposes of 
cultivation. Bordering on the sieve-tubes are extremely 
narrow long elements which are albuminous cells. Ordinary 
phloem-parenchyma, consisting of broader, shorter cells, is 
also present. 
Returning once more to the transverse section from the 
lower part of an adult stem, we find, immediately abutting 
on the normal vascular ring, a second ring equal, or almost 
so, in breadth to the first. The inner portion of its wood 
abuts directly on the outer, first-formed phloem of the normal 
ring (Fig. 2). 
It may be mentioned here that the segments of each of 
these two successive rings do not always lie evenly parallel 
one with the other. Occasionally one sees a large, wedge- 
shaped segment, really appertaining to the second ring, which 
has become pushed out of line, and lies embedded in a large 
medullary ray of the normal ring ; so that it is at first not 
quite easy to tell to which of the two rings it really belongs 
(Fig. 1). There is, indeed, especially in the lower region 
of the stem, great irregularity in the whole structure, which 
may be partly due to the free play afforded to the expansion 
of the parenchymatous tissues in a stem whose vascular 
portion is so loosely compacted. 
This first anomalous ring succeeds the normal ring just as 
has been described for Cycas and Encephalartos ; and, at first, 
one would suppose that, in the plant I am describing, there 
was no more to be added to this point. But, on a subsequent 
more minute examination of the region where the phloem of 
