246 Diseases of Greenhouse Crops 



is a degenerate flowering plant. According to Harsh- 

 berger,* the embryo of Orobanche has no trace of 

 root and stem, but it consists of a spiral filament of 

 delicate cells which feeds on the stored reserved food 

 of the seed. Upon coming in contact with the roots 

 of a suitable host it adheres itself closely and swells 

 considerably, assuming a flask-shaped appearance. 

 Secondary filaments are now produced from the 

 flask-shaped body which bore in and penetrate into 

 the vascular system of the roots of its host, where 

 it receives its food. At the point of union between 

 host and parasite, a bud is formed which later de- 

 velops into a thick flower bearing stem which grows 

 out above ground. 



The Croton (Codiczum variegatum) 



Cultural Considerations, Care should be taken 

 **^t to allow the plants to become pot bound. The 

 best foliage color is obtained when exposed to full 

 sunlight. The plants do well in a moist house with 

 frequent syringing of the foliage. The tempera- 

 ture at night should never be permitted to go down 

 below 70 degrees. 



Diseases of the Croton 



The Croton is considered a very hardy plant, but 

 one disease is of importance to the greenhouse man. 



* Harshberger, J. W., A text book of mycology and plant path- 

 ology: 299, 1918. P. Blakiston's Son & Co., Philadelphia, Pa. 



