166 



had been prevented from settling on the leaves with the 

 formerly described resuit. 



Similar tumours as the yellow, thickened leaf-tips of 

 Gneium G-nemon really are, hâve also been repeatedly 

 observed with other plants and described under the name 

 of „yellow specks" (Gelbfleckigkeit), oedemata or intumes- 

 cences. The Word „Intumescentia" was introduced into 

 phytopathological nomenclature by Sorauer with the défi- 

 nition '): „Intumescentia" sind „diejenigen Erscheinungen, 

 die das gemeinsame Merkmal haben, als kleine knôtchen- 

 fôrmige oder drûsige Auftreibungen der Blatter aufzutreten, 

 die meist an diesen Stellen gelb verfarbt erscheinen und 

 eine aussergewôhnliche Zellstreckung ohne wesentliche 

 Zellvermehrung zeigen". That the thickened leaf-tips of 

 Grnetum Gnemon are not indeed „ kleine Auftreibungen" 

 and do présent „wesentliche Zellvermehrung" need not 

 necessarily prevent us from counting them among the 

 intumescences, since as well very large 2) or mutually 

 coalescent ^) as typically hyperplastic *) intumescences hâve 

 been described for other plants. 



We cannot now deal with the very divergent views of 

 différent investigators about the cause of the formation of 

 intumescences; we will only mention that in most cases 



1) P. Sorauer, Die symptomatische Bedeutung der Intumes- 

 cenzen (Bot. Zeitg. 48 Jalirg. 1890. pag. 241). 



2) H. V. S c h r e n k, Intumescences formed as a resuit of chemical 

 stimulation (Missouri botan. garden. 16*'' ann. report. 1905. pag. 125). 



3) Miss. G. E. Douglas, The formation of intumescences in 

 potatoplants. (Bot. Gazette Vol. XLIII. 1907. pag. 233). 



4) E. K û s t e r, Ueber experimentell erzeugte Intumescenzen. (Ber. 

 deutsch, bot. Ges. Bd. XXI. 1903. pag. 452). P. S r a u e r, Ueber Gelb- 

 fleckigkeit. (Forsch. a. d. Geb. d. Agrik. Phys. h. v. Dr. E. W 1 1 n y. 

 Bd. IX. 1886. pag. 387) and Intumescenz bei Solanum floribundum. 

 (Zeitsclir. f. Pflanzenkrankh. Bd. VIL 1897. pag. 122). 



