Abstract
Summary: Quantitative determinations of chlorophyll showed thatCuscuta hyalina and Striga hermonthica possesschlorophyll. No trace of chlorophyll was found in Orobanche ramosa. Autoradiographic evidence showed that both radiocarbon and radiophosphorous moved from host to parasite in alt three species. Photosynthesis occurs in S. hermonthica when the parasite is isolated from its host. The adventitious roots of S. hermonthica and O. ramosa appear to be functional in absorbing a proportion of the required inorganic substances and water. S. hermonthica is a hemiparasite,O. ramosais a holoparasite butC. hyalinais best described as a partial parasite.