192 REMINISCENCES OF 



and only referred them to some doubtful family of 

 monocotyledons. In 1846, Mr. Dawes of Birming- 

 ham made a much closer approximation to the truth 

 when he suggested that they were more probably the 

 piths of some arborescent plant like Lepidodendron. 

 In his " Tableaux des Genres des Ve'ge'taux Fossiles," 

 published in 1849, Brongniart still inclined to his 

 monocotyledonous suggestions, but at the date in 

 question no definite conclusions had been arrived at. 

 About this time I obtained some fine specimens of 

 these objects, especially a young twig, in a good 

 state of preservation, from the coal-field of Coalbrook- 

 dale, for which I was indebted to my friend, now 

 Professor Prestwich. 



Combining my microscopic preparations of this 

 plant with others in my cabinet, I succeeded in 

 discovering the interpretation of their structure. I 

 should say that what looked like a pith resembled a 

 vertical column of coins like pennies, but in most 

 cases thicker and with very prominent round edges. 

 So far as he went, Dawes was right in his sugges- 

 tion that Sternbergia resembled a cast of a pith, but 

 none of the observers who had studied these objects 

 seem to have been familiar with any living plant in 

 which a similar pith exists. 



It soon struck me that it had been of the form 

 known to the later botanists by the name of " dis- 

 coid." In this type the periphery of the medulla is 

 a continuous thin layer of cellular cylinder ; but its 

 more central portion splits up horizontally into 



