BRIEFER ARTICLES 



PHILIPPE EDOUARD LEON VAN TIEGHEM 



(with portrait) 



The younger generation of botanists perhaps does not realize the 

 important part played by van Tieghem in the progress of botany. In 

 recent years his publications, chiefly in the Annates des Sciences Natu- 

 relles, have had to do with the 

 anatomical details of various 

 families. Such work attracts very 

 little attention in these days. In 

 1886. however, when van Tieghem 

 and Douliot published the paper 

 entitled "Sur la polystelie," a new 

 epoch in the history of anatomy 

 was introduced. It was the first 

 formal statement of the stelar 



theory, 



as we have had it ever 



since. Before that time the sec- 

 tion of a stem was described as 

 consisting of "f undamental tissue 1 ' 

 which vascular strands traversed 

 in various ways. In other words, 

 pith, medullary rays, and cortex- 

 were all regarded as regions of the 

 same tissue. It may be said in 

 passing that this old conception is 

 still current in certain texts. It 

 was van Tieghem's good fortune 

 to present first the fact that the 

 stele is an entity, quite distinct 

 from the cortex. Curiously 



enough, the conception of the polystele presented in the original thesis 

 has disappeared, and the rest of the stelar terminology of VAN Tieghem 

 has been set aside, but the conception remains. 



Van Tieghem was born in 1839 at Bailleul. In 1879 he was appointed 

 Professor of Botany at the Museum of Natural History (Paris), and 



qL Vn#i~ biloA 



527] 



[Botanical Gazette, vol. 58 



