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The Structure and Parasitism of Aphyllon 

 Uniflorum, Gray. 



iWITH PL A TES XIII-SV.) 



By Amelia C. Smith, B. S. 



Aphyllon imiflorum^ or the Naked Broom-rape, belongs to 

 the large parasitic order of the OrobanchacccB, and is by some 

 included in the genus Orobanchc. It is typically a North 

 American species, and is a pure parasite, being without 

 chlorophyl. The present study was undertaken at the sug- 

 gestion of Professor ]\Iacfarlane, and was carried out under his 

 direction. All of my material has been collected from one 

 very limited locality at Glenolden, Pennsylvania, where it 

 grows luxuriantly. It appears toward the end of May, when 

 Aster plants are about nine inches high, and by the end of 

 June the seeds are matured and the plant is withering. I have 

 invariably found it parasitic on the roots of Aster corymbosuni. 

 Chatin states that it is parasitic on Solidago and other Synan- 

 theras, while Beck gives the following list of host-plants : 

 Species of Artemisia, species of Solidago, Sedian stowpcta- 

 han (!) By carefully cutting out and lifting a large sod con- 

 taining several Asters and a clump of Aphyllon, and then 

 washing away the soil until the roots were exposed, I was able 

 to trace the root-connections with certainty. 



Methods. 



Some of my material was killed in saturated aqueous solu- 

 tion of corrosive sublimate, a smaller quantity in absolute 

 alcohol, and a great deal of it was simply preserved by plac- 

 ing it at once in 70 per cent alcohol. For general structure, 

 all of the above methods gave equally good results. For 



