352 PROCEEDINGS OF THE ACADEMY OF [May, 



THE FORM AND STRUCTURE OF THE MYCODOMATIA OF MYRICA CERIFERA L. 



BY JOHN W. HARSHBERGER, PH.D. 



Within the last decade or two considerable progress has been made 

 in our knowledge of the enlargements, galls, tubercles and coralline 

 outgrowths on the roots of the higher chlorophyll-bearing plants. 

 Some of them are due to insects, others are due to a perversion of the 

 physiologic activities of the plants on which they are found, while 

 others are attrilDutal^le to the stimuli occasioned by bacteria, slime 

 moulds and higher fungi. Our information concerning the tubercles 

 on the roots of the Leguminosse is reasonably complete, thanks to the 

 energies of Hellriegel, Willfarth, Winogradsky and others. Magnus^ 

 has summed up our knowledge of the growths joroduced by subterra- 

 nean fungi in a recent paper. He describes systematically the fungi 

 known to live as subterranean parasites, but barely mentions those 

 forms of enlargement called mycodomatia. Mycodomatia were known 

 to the botanists of a century ago. Meyen^ looked upon them as para- 

 sites having a habit in this respect similar to plants of the natural 

 orders Balanophoracese and Orobanchacese. Schacht,^ who was the 

 first to give a fairly satisfactory account of their external appearance, 

 regarded them as normal growths upon roots, but later he considered 

 them as abnormal. Jager* considered them as due to insects. Wo- 

 ronin,-^ in a paper published in the Memoirs of the Academy of Sciences 

 of St. Petersburg, believed that the coral-like swellings on the roots of 

 the black alder were due to a fungus closely related to one described by 

 Nageli inhabiting the roots of various species of Iris and called by him 



^Magnus, P., "Unsere Kenntniss unterirdisch lebender streng parasitischer 

 Pilze und die biologische Bedeutung eines solchen unterirdischen Parasitismus," 

 Abhandhingen des hotanischen Vereins der Provinz Brandenburg, XLIV (1902), 

 pp. 147-156. 



- Meyen, "Ueber das Hervorwachsen parasitischer Gewiichse, etc.," Flora, 

 1829, .S. 49. 



^ ScHACHT, "Die Pflanzenphvsiologie und Herr Dr. G. Walpers in Berlin," 

 Flora, 1853, pp. 1-13; also "Der Baum," 18(50, S. 172-174. 



^ Jager, "Ueber eine Krankhafte Veriinderung der Bliithen Organe der 

 Weintraube," Flora, S. 49. 



* WoRONiN, "Ueber die bei der Schwarzerle (Alnus Glutinosa) und der gewohn- 

 lichen Garten-Lupine (Lupinus mutabilis) auftretenden Wurzelausschwellungen," 

 Memoires de V Academie ImperiaJe des Sciences de St. Pctersbourg, VII Serie, 

 Tome X, No. 6, 1866. 



