278 S topes. — A Note on Wounded Catamites. 
canals undisturbed, as can be seen in his diagram (loc. cit ., Fig. 80). The 
callus wood in his case, therefore, though bending across to close up the 
wound, is simply formed in the normal direction. As the cylinder was 
not broken through, the 
edges could not inroll, 
thus making the case 
much simpler than in 
the larger stems with 
deeper wounds. 
In the latter, as may 
be seen in PI. XXIII, 
Fig. 1, c , the wound- 
cambium was very active 
in the neighbourhood of 
the injury, curving in 
and out round the pri- 
mary bundles, adding 
new tissue where there 
was room for it. The 
injured primary strands, with small quantities of secondary tissue associated 
with them, have been cut off and isolated from the rest of the wood by 
this cambium band (see PI. XXIII, Fig. 1, /), and had evidently partly 
decayed while the rest of the stem was still vigorous, judging from the 
different states of preservation of the two tissues. 
That there was a definite formation of inverted wood in addition to 
the callus wood curving 
round the edges may be 
seen by the position of the 
cambium zone, which ex- 
tends round the primary 
strands some distance be- 
yond the actual wound- 
gap. This cambium does 
not simply form a mass of 
new tissue, but tends to 
produce bundles facing 
the normal ones (see PI. 
Diagram 2. Neighbouring sect. R. 101. x 2. Externally YYTTT Ficrc: t nnrl o A 
wound further closed, inrolled wedges of callus less developed. > 1 s b * > V* 
The inverted masses of 
tissue are thinner-walled than the bulk of the woody elements, but are 
thickened and definitely pitted, as examination with the high power clearly 
reveals. Where the callus wood is cut obliquely it shows that some of the 
tracheides are very irregular and much curved. This has been described 
X 
Diagramt. Trans, sect, of wounded Calamite, x 2. Wound 
at x. externally just closed up. In the pith cavity on either 
side are the curved wedges of callus wood completely inrolled. 
R. 100, Manchester University Coll. 
