9 



A Case of Gametic Coupling in Pisum. ■ 

 By Philippe de Vilmorin and W. Bateson, F.B.S. 

 (Received March 2,— Read March 30, 1911.) 



For some years past a variety of culinary peas has been grown at 

 Verrieres-le-Buisson, remarkable for the fact that it has no tendrils, each of 

 the normal tendrils being represented by a leaflet. The figure shows the 

 appearance of the leaves of this variety, with leaves of normal plants for 

 comparison. 



Fig. 1. — The four right-hand leaves are from " Acacia " peas ; the three left-hand leaves 

 are from normal plants. The figure on extreme left shows a leaflet with a tendril 

 opposite to it. Such asymmetries are common in the normal types. 



These " Acacia " peas, as they are called, breed perfectly true. Their 

 origin is unknown. The variety has wrinkled seeds. 



Crosses were made at Verrieres between the Acacias and a variety having 

 normal tendrils and round seeds. The tendrilled character was fully 

 dominant in ~F U which, of course, bore both round and wrinkled seeds. 

 When these seeds were separately sown it was observed that the round 

 seeds gave rise almost exclusively to tendrilled plants, and the wrinkled 

 seeds almost exclusively to Acacias, though there were a few exceptions each 

 way. 



