OF BUCKXEYA QUADEIALA, B. ET H. 11 



veloped overlapping a greater part of the periphery of the host- 

 root. The folds, in the majority of eases, are in two or three 

 pairs, among which the inner ones are always smaller, appearing, 

 in cross-section, like a pointed process frequently directed toward 

 the interior of the haustorium (Fig. 7 at'). In Thesium Pitra 1 ' 

 and Solms j) mentioned the occurence of numerous folds in the ease 

 in which it had attacked some monocotyledonous roots, but only 

 a single pair in the ease of dicotyledonous roots. The latter 

 author regards this difference in the number of the folds in 

 monocotyledonous and dicotyledonous roots, to be the results of 

 differences in the resistances exerted by the host-roots for the 

 penetration of the haustorium and of difference in the degree of 

 its development. He observed that the fold-formation ceases as 

 soon as the apex of the haustorium has applied itself to the. 

 endodermis of the host, though many folds may, up to that time, 

 have been formed successively. 11 He observed also that, in dicoty- 

 ledonous roots, the penetration of the haustorium and its con- 

 nection with the wood of the host are very easily accomplished, 

 the differentiation of the tissue in the haustorium being early 

 finished before the formation of any fold other than the primary 

 vnv has taken place ; while in monocotyledonous roots, as the 

 resistance is greater, the haustorium is allowed to produce numerous 

 folds till its tissue is completely differentiated.^ So he regarded 

 a, certain cell-mass in the corner of the adult sucker in a dicoty- 

 ledonous root as the rudiment of a secondary fold.'- 1 have not 

 yet obtained any haustorium of Buckley a on a monocotyledonous 



1). loc. cit. 



2). loc. cit. 



3). Inc. cit. p. ÖÖ-1. 



A), loc. cit. p. 555. 



5). loc. cit. Tai". XXXIII, Fig. 2 hi. 



