Scrophulariaceae and Orobanchaceae 145 



with ample green leaves that have evolved along at least three 

 main lines. One line, as beautifully traced by Dr. Henderson 

 (11) in a recent paper, shows condensing and degrading simpli- 

 fication through saprophytism till low herbaceous shrubs with 

 few scattered leaves like Chimaphila are reached, while these 

 lead to the colorless greatly degraded genera of the Monotro- 

 paceae like Sarcodes and Monotropa. Still another line leads 

 to the parasitic Lennoaceae, the carpels of which have probably 

 increased in number by subdivision of a primitive five, that re- 

 main as many celled but the ovules have become reduced to two 

 or one in each cavity. A third line passes to highly evolved 

 types like the Azaleas, Kalmias, and Rhododendrons with ample 

 leafage, and roots that are nonsaprophytic or only slightly sa- 

 prophytic and ovary that is five-celled. 



In the Gentianaceae, that frequently tend to be slightly or 

 markedly saprophytic, the ovary is still two-celled in the subdi- 

 vision Exacineae. In others like Lisiantheae the ovary is strict- 

 ly one-celled but has deep almost adjacent placental ridges. In 

 the Gentianeae the one-celled ovary has shallow ridges that 

 reach a climax of shallowness in the colorless degraded sapro- 

 phytes Voyria and Leiphaimos. 



In the Convolvulaceae the ovary throughout is typically two- 

 celled and this is retained in species generally of the parasitic 

 genus Cuscuta, but a one-celled parietal condition is present in 

 Erycibe. Similarly in Rafnesiaceae, the ovary is one-celled. 



From the above it is abundantly evident that alike in sapro- 

 phytic and parasitic families simplifying and degrading sapro- 

 phytism and parasitism nearly always are accompanied by a 

 transition from a several-celled central type of placentation to 

 a one-celled parietal type. 



Accepting the foregoing as an indubitable fact, the question 

 may now be asked: Can close morphological affinity be traced 

 from Scrophulariaceae through types that become more or less 

 parasitic and eventually degraded colorless parasites, to forms 

 typical of the purely parasitic and non-chlorophylloid Orobanch- 

 aceae? The demonstration of this is the main thesis of the pre- 

 sent paper. As strongly favoring such a position, it may be 

 noted that in such a genus as Gerardia the most gradual transition 

 can be traced from tall leafy green species, like G.flava (Aureo- 

 laria villosa) to G. pedicularia, thence to G. purpurea, to G. oli- 



