PROGRESS IN THE STUDY OF VARIATION. 565 



But Mr. Fletcher by starting with a normal female vionacha 

 raised by selection among her offspring, successively re- 

 peated for five years, a series of which a few in the latter 

 years are practically monacha, and in this series numerous 

 intermediates occur. 



In each case the indication is the same, that the results 

 depend on the strain employed. It is greatly to be hoped 

 that these experiments may be repeated and detailed statis- 

 tics of the results published. 



So far as I can learn those that have been hitherto per- 

 formed have not been for the most part recorded in any 

 detail and the specimens have been largely dispersed. 



The other case which I shall take in illustration of a 

 similar phenomenon is that of the hairy and smooth forms of 

 the Cruciferous plant, Biscutella IcBvigata. I have had oppor- 

 tunities of observing this plant in several localities in the 

 wild state, and in a recent communication to the Royal 

 Society Miss E. R. Saunders has given the results of 

 experimental cultivation and artificial fertilisation of its 

 varieties. The facts are these. The plant is a common 

 Alpine species with a rather wide distribution. Some 

 authorities describe it as hairy, others as glabrous. Gener- 

 ally it is stated that it may be either hairy or glabrous. The 

 essential fact to the student of variation is that in certain 

 localities the hairy and the glabrous forms may occur side by 

 side in the same meadow or on the same rock. In my 

 experience the hairy form is the commoner. The plant is 

 common, for instance, in the Val d'Anniviers, at Berisal, 

 near Airolo, and elsewhere, exclusively in the hairy form. 

 The leaves and stems are thickly covered with a short 

 pubescence, varying in texture, but commonly the hairs are 

 stiff. But in the Val Formazza, side by side with the hairy 

 plants, are others exactly resembling them in the rest of 

 their structure, but having the surfaces of the leaves and 

 stems smooth and devoid of hairs. In the great majority 

 of these smooth-leaved plants, however, the margins of the 

 leaves and the leaf-teeth, often also the mid-rib, bear hairs : 

 it is the surfaces which are smooth. In this valley, both 



