112 BRITISH GALLS 



Professor Tra.il, in 18S3, recorded the occurrence of 

 TyUnchis galls on the Mouse-ear Hawkweed. The flower 

 head was swollen, the stalk contorted and coiled on its axis. 

 The species of eelworm responsible for these malformations 

 is unknown; Connold designated it Tyknchus hieracii, but 

 did not describe it. 



Continental Eelworm Galls 



In addition to the ten species indicated above, Houard 

 describes in " Zooc6cidies des Plantes d'Europe " six others 

 that are gall-causers on the Continent. I am not aware 

 that they have been observed in Britain, but some allusion 

 to their galls seems desirable, as it is quite likely that all 

 will be found to occur in this country. 



Tyknchus Haversteini Ktihn deforms the entire plant in 

 Medicago sativa. The shoots remain closed, and are four 

 times in excess of the normal thickness; they are also 

 contorted and carry deformed leaves which are often trans- 

 formed into complete scales (No. 3,516). 



Tyknchus agrostidis Steinb. attacks various grasses of the 

 genus Agrostis, causing the ovary to become elongated and 

 tinted violet, and the glumes hypertrophied (No. 185, etc.). 



Tyknchus hordei Schoyen gives rise to nodosities on the 

 top of the radical root in Elymus arenanus Linn. (No. 350). 



A species of Tyknchus, probably T. hyacinthi Prillieux, 

 causes yellow spots on the leaves of a Eucharis. The spots 

 become brown later, and there are clearly deiihed depressions 

 on the lower surface (No. 433). 



Tyknchus nivaUs Kflhn causes swellings on the stem and 

 leaves of LeontopoUum (Gnaphalium) alpinum (No. 5594). 



Tyknchus phalaridis Steinb. attacks Phkum pratense. The 

 glume is elongated, thickened, enrolled like a horn around 

 the pistil (5 to 7 mm.), and of a yellowish tint. The ovary 

 acquires the shape of a cylinder or spindle, and becomes 

 yellowish-red or dull purplish-brown. The stamens are 

 abortive ((Nc, 179). 



