]89 



Further Studies on Anomalous DicotyledOxNous Plants. 



By D. M. ]Mottiei?. 



(Abstract.) 



The stiidip.s referred to deal with the development of the embryo 

 with special reference to the origin of the cotyledons in Actcii alba, 

 Stylnplioriiiii diiJiijllinii and Sancju'uiariti ccniadeiisis. In the origin of the 

 cotyledons all three species show, in varying degrees, the distinguishing 

 characteristics of typical anomalous dicots. In each the embryo be- 

 comes i)ear-shaped before any indication of the cotyledonar primordium 

 is apparent. The primordium of the cotyledons now appears as an 

 almost complete, circular, ridge-like outgrowth from the margin of tlie 

 broadly truncated end of the emiiryo. With tlie further growth oi: this 

 ridge a bifurcation soon appears at a point exactly opposite the pri- 

 mary cleft of the primordium, so that the Iavo young cotyledons, which 

 may or may not be of the same size, seem to represent two separace 

 and opposite lobes of the distal end of the embryo with one of tlie 

 clefts a little deeper than the other. In some cases (Stylophoruni) the 

 two cotyledons seem to arise as separate and independent outgrowths. 

 but a little later their common base grows faster on one side than 

 on the other, and in this manner the two clefts or liifurcations become 

 unequal in depth. 



It is important to note, however, that in embryos of different indi- 

 viduals of the same species the anomalous character is much more 

 strongly marked than in others. 



On the Germination of Certain Xative Weeds. 



By Stanley Coulter. 

 (By title.) 



