82 DESCRIPTIVE CATALOGUE 



marked annual rings, of which 17 are present, wholly or in 

 part. This can he seen slightly enlarged in PI. Ill, fig. 1. The 

 details of the wood are beautifully preserved in a dark silicified 

 medium, but the wood was evidently much bored by teredos 

 before fossilisatior, for a number of large borings are filled with 

 the granular matrix. This also can be clearly recognised in the 

 photographs, PI. III. 



TOPOGRAPHY OF THE STEM. The pith is preserved and is large, 

 measuring nearly 3 mm. in diameter. The cells composing it 

 are all of one kind, and towards the centre are large, round, 

 and with small intercellular spaces. The pith is roughly 

 circular, but the deep bays of primary wood give it a stellate 

 character with rather long points, formed by about 12 principal 

 bundles. 



The primary wood is well preserved and is arranged in well- 

 marked bundles (see PI. III. fig. 2). There is a medullary sheath 

 of small cells round the protoxylems, but no centripetal wood 

 has been detected. The secondary wood is in well-marked regular 

 rings (see PI. Ill, figs. 1 & 3). About 25 to 40 elements in radial 

 series compose each ring, the largest of which measure about 

 2 mm. in extent. The extremely thickened autumn wood forms 

 a broad zone in each ring, and is on the average about ^ the 

 total thickness of the ring. The tracheids are rounded off at 

 the corners, and adjacent elements are generally on alternating 

 tangents so as to fit into each other. 



Resin-canals, either isolated or in rows, are found in the second 

 and all subsequent annual rings, principally in the middle of 

 the autumn wood and in a few cases just outside it (see text- 

 fig. 17 & PI. Ill, fig. 3). In some cases a row of canals almost 

 encircles the whole stem, in others a ring may contain fe\v 

 isolated canals. These canals all run vertically, and, so far as 

 I can discover, there are no horizontal canals. 



Medullary rays are numerous and very conspicuous in trans- 

 verse section. All are uniseriate, and are 1-15 tracheids 

 distant, principally 4-6. The ray-cells appear to be all of one 

 kind, though a number of them contain resin-like contents ; 

 all their walls are thickened and pitted. The rays vary from 

 1-20 cells high, the greater number being from 3-8 cells in 

 height. 



DETAILS OF ELEMENTS. The cells of the pitli are all roughly 



