Scrophulariaceae and Orobanchaceae 149 



Did we know the parasitic root relations of Harveya and Ilyo- 

 banche,these in all probability form a more perfectly graded con- 

 nection between the two supposed distinct orders. 



From the above we pass to Orobanche, e. g., 0. minor 

 (Plate XII, Fig. 4), in which a dense mass of secondary roots 

 starts from a swollen shortened primary-root and these roots 

 form by their surfaces intimate and close connections with the 

 host roots, as described and figured by Koch (16). In 0. cru- 

 enta the primary root swelling becomes more pronounced and 

 the place of junction between stem and root is collar-like in ap- 

 pearance. Here two lines of deviation seem to start in conden- 

 sing degradation. 



One line, simplifying and short-lived, leads to Aphyllon 

 (Plate XIII, Fig. 6) in which as figured by the writer there is 

 even more close and extensive parasitic connection with the host 

 than in the previous types and the parasite itself, in that sec- 

 ondary and probably primary roots parasitize. At the base of 

 the short stem arises the primary root, now slightly swollen, 

 and from this are given off secondary roots in such numbers as 

 to form a very much tangled mass. 



Another line leads to the larger stronger genus Epiphegus 

 (Plate XIII, Fig. 7) of annual duration, in which a tuberous 

 swelling from a half inch to an inch across represents a fused pri- 

 mary root below and a greatly condensed vegetative stem-axis 

 above. From the lower part or primary root short and now 

 functionless rootlets start, while from the condensed stem adven- 

 titious roots, similar in relation to the secondary ones, arise at 

 any point of the stem axis. Accordingly parasitic connection 

 with the host is easily and directly made by the germinating 

 primary root as already pointed out by Cooke and Schively (17). 

 The roots of Epiphegus form around and above the beech roots 

 on which this is parasitic. The secondary and adventitious 

 roots are short and delicate. 



In Conopholis (Plate XVI, Fig. 33), which may be regarded 

 as the climax type of the group, the root system so far as known 

 is entirely hidden from external view, being represented by a 

 large swelling and which usually terminates the oak root on 

 which it grows. Alike roots and leaves have been entirely ab- 

 sorbed, although in Epiphegus rudiments of both are present. 

 From the swelling arise numerous flowering shoots. 



