TRANSLOCATION OF CARBOHYDRATES 267 



tubes, as Lecomte has pointed out) is proportional to the 

 amount of wood. In the case of Monocotyledons this proportion 

 is more constant, since here the phloem consists almost entirely 

 of sieve-tubes and companion-cells. In some Dicotyledons, 

 however, as in Glycine and the root of Lappa major, although 

 the phloem is fairly well developed, only a few small sieve-tubes 

 occur. On the other hand, in Vitis, Cucurbita, Lagenaria, Im- 

 patiens, etc., the sieve-tubes and companion-cells form nearly 



Fig. 9. — Bundle ending in leaf of Fuchsia globosa. 



A, vessel ; B, phloem parenchyma ; C, small sieve-tube ; D, large companion-cell ; 



E, transition-cell ; F, parenchymatous bundle sheath. 



Fig. 10. — Transverse section of fine bundle of Ecballinin elatenim. 



Lettering as in Fig. g. 



(Figs. 9-10 after Haberlandt.) 



the whole of the phloem and only a small amount of parenchyma 

 is present. 



Westermaier and Ambronne, in 1881, stated that the vessels 

 and sieve-tubes of climbing plants are the largest in diameter 

 and their opinion is quoted without qualifications by Haberlandt 

 in the third edition of his Physiologische PJlanscnanatomie. 

 Herail, in 1885, confirmed some of the results of Westermaier 

 and Ambronne and also showed that the diameter of the largest 

 vessels in a climbing species is often very much greater than in 



