ur 
218 DR. D. H. SCOTT : 
On the whole of the characters available for comparison, it seems clear 
that C. Saturni is very distinct from C. annularis and C. americana, while 
the two latter species show a remarkably close agreement with one another. 
ÜALAMOPITYS AMERICANA, Scott & Jeffrey. 
A short summary of the chief characters of this species is all that need be 
given here, 
Primary xylem-strands eccentrically mesarch, with the centrifugal portion 
smaller and smaller-celled than the centripetal. Strands united laterally to 
form an almost closed xylem-ring. 
Pith “ mixed,” containing a varying proportion of medullary tracheides. 
Leaf-trace dividing into two as it passes through the secondary wood. 
Each leaf-trace bundle, where it leaves the wood, surrounded by a zone of 
secondary thickening. 
Secondary wood with high, multiseriate medullary rays, not enlarged 
outwards, "Tracheides with several series of alternating bordered pits on the 
radial walls, 
Leaf-base with the structure of Kalymma, containing a number of mesarch 
bundles, each with from 2 to 5 protoxylem-groups. 
The details are fully described in the paper by Prof. Jeffrey and myself 
(1914), supplemented by the more complete account of the course of the leaf- 
trace given in the first part of the present communication. 
CALAMOPITYS FASCICULARIS, Scott. 
Lristophyton fasciculare, Zalessky. 
This species was shortly described, under the name Araucarioxylon 
Jasciculare, in 1899 (Scott, 1899, p. 615) and a full illustrated account was 
given three years later, when I placed it in the genus Calamopitys (Scott, 
1902, p. 332). No new specimens have come to light since then and there is 
little to add to the published deseription. "The species is mentioned and a 
figure given by Dr. Zalessky (1911, p. 22 ; Pl. 3. fig. 7), who contests its 
affinity with Calamopitys and transfers the plant to his new genus Evristophyton. 
A brief recapitulation of the principal features may be given here, reserving 
the discussion of the systematic position to the conclusion of the paper. 
The pith is small (2-3 mm. in diameter) and of very uniform parenchy- 
matous structure; it contains no sclerotic nests. A few of the cells have 
dark contents and may possibly have been secretory in function. There are 
no medullary tracheides. 
The pith is surrounded by a ring of about 8 or 9 primary xylem- 
strands, of mesarch structure (Scott, 1902; Pl, 3. fig. 1). They are of 
very unequal size. Those which are about to enter the secondary wood 
as leaf-traces are very large, from 0:8 to 1 mm. in diameter. Those 
eut lower down in their course are much smaller, diminishing rapidly as 
