Dr. M. C. Stopes — The Kentish Rag ' Dragon-tree'. 57 



Previous work on extremely ill-preserved woods in greensand 

 matrices had prepared me to deal with wood in the condition of 

 a white, semi-silicified, fibrous mass, which crumbles to the touch. As 

 such remains are the only form which vegetable fossils take in some 

 deposits, it may be of value to note the simple point of technique 

 which I have found useful. With such specimens collodium casts 

 are not obtainable, as the collodium sinks into the fibrous surface and 

 does not form a proper film. Ordinary sections are out of the question ; 

 examination with a hand lens gives one no clue to the nature of the 

 wood, because it is generally so incompletely preserved as not to show 

 even its annual rings. I have found, however, that if one selects 

 a portion of the wood remains free from matrix, the point of a sharp 

 pen-knife will free with the lightest touch some of the fibrous powder 

 of the wood. If this powder is then mounted on an ordinary slide, 

 soaked in water for a short time under a cover-glass, it will be found 

 that it consists of short lengths of individual tracheids, generally 

 separate from each other or lying in pairs. 



Some of the powder from the pulverizing wood, as seen under the microscope, 

 showing the separate lengths of the tracheids, some of which show 

 bordered pits. 



Many of these tracheids show no markings, but in most woods that 

 I have examined, however poor they may be, at least a few of the 

 tracheids show their characteristic pittiugs. In this way I have 

 recognized in minute scraps of pulverizing wood true Abietineous 

 pitting, with round bordered pits in single rows, and other woods with 

 Ilrachyphyllum-like pits in irregular pairs. The sharpness of the 

 border in these bordered pits (which show sometimes the small central 

 opening also) is remarkable, considering the unpromising nature of the 

 material. In a few cases short lengths of medullary rays accompany 

 the tracheids, but in general one does not get more than the tracheal 

 markings to work upon. These, however, are sufficient to determine 

 the main group to which the plant belongs. 



