1 6 Wilson — Observations on 



well as Fig. 4 showed by higher magnification the spiral 

 tracheae, which make up about half of the fibro-vascular 

 bundles. The dark spots at the base of all these figures are 

 the sclerenchyma masses, which just below these buds make 

 up almost the entire mass of the tubercle. 



Each cell of the parenchyma of the shoot, in addition to a 

 well-defined nucleus and nucleolus, contains from one to seven 

 clear spherical, highly refractive bodies, on which even hydro- 

 chloric acid made no visible impression. Nevertheless, a set 

 of sections left over night in the acid had in the morning 

 scarcely a granule left, while another set which remained in 

 alcohol over night still retained them. 



These bodies are most numerous in the apex of the stalk. 

 Further down they have lost their spherical outline, look to 

 be disintegrating and finally disappear. About the region 

 where they begin to disappear the patches of sclerenchyma 

 begin to appear. 



The bundles are well differentiated almost to the apex. 

 They are made up, in about equal halves, of xylem and phloem, 

 the former consisting of spiral tracheae and wood cells. In the 

 adult phloem a few sieve tubes are found. The relatively 

 large amount of phloem is interesting and characteristic of 

 parasites in general. For obvious reasons such a plant does 

 not need much wood, and the rather large amount in this 

 case has some relation to the fairly abundant stomata, which 

 are so often lacking in other plants of a similar habit. 



Cross sections of a very young rhizome, just before it leaves 

 the tubercle, seem to indicate that the outer row of bundles is 

 first formed and that the inner circle is developed slightly 

 later. Nevertheless, since the inner row represents the normal 

 group of bundles, this is so contraiy to what might be ex- 

 pected that my evidence seems to me scarcely to justify more 

 than the suggestion that the order of development may be as 

 indicated. 



Chatin figures a third rov/ of bundles — leaf-trace bundles 



