Ko.493] THE PHENOGAMOTJS PARASITES 21 



mostly perennial herbs, is confined to limited underground 

 pilfering. It is the simplest form of phenogamous para- 

 sitism but it is as persistent and hereditary as are the 

 more complex forms, and it is practised by a large number 

 of genera and species which have numerous near normal 

 relatives. Because they have normal roots and leaves 

 and produce chlorophyl they begin life with the ability to 

 procure an honest living, but they seem to be unable to 

 resist their inherited parasitic inclinations. The develop- 

 ment of haustoria at the points of contact of their roots 

 with roots of other plants begins after their germinative 

 birth from a normal embryo and an early stage of full 

 self-support obtained from the soil; but so firmly fixed 

 is the habit of pilfering in these plants that when they 

 have been experimentally forced to live honestly in good 

 soil, but beyond the reach of roots of other plants, they 

 have ceased to thrive, as if they were insufficiently 

 nourished. 



Group II 



Parasites attached to the stems and branches of woody 

 hosts upon the bark of which the seeds germinate, being- 

 affixed there by their glutinous covering. Embryo differ- 



