107 



of great interest, since in Tecoma radicans Juss, a plant in 

 which very similar secondary fibro-vascular formations occur in 

 the pith, the development of a row-formed cambium is never- 

 the-less always preceded by the appearance of well-developed 

 groups of sieve-tubes ^), which have the irregular arrangement 

 characteristic of primary phloem. 



The amomalous cambiums of lodes tornentella appear, in the 

 internodes , at first as four short separate strips , those on each 

 side of the ellipse subsequently uniting to develope the inter- 

 mediate medullary rays just as the cambiums, which have 

 arisen in normal bundles, extend gradually to the parenchyma 

 lying between the bundles. To discover the origin of these four 

 short strips of cambium in lodes it is necessary to investigate 

 the nodal regions. This can be done most satisfactorily by 

 means of continuous series of cross-sections , and following such 

 a series from below upwards, that is to say, from the older 

 internode through the node to the younger internode, the 

 author has observed the following changes in the relations of 

 the tissues. The oft-mentioned elliptical ring of first formed 

 secondary wood becomes longer and its tissue takes on a some- 

 what looser character. The already much thickened leaf-trace- 

 bundles gradually separate themselves from the ring, leaving 

 wide gaps at the ends of the ellipse. The strips of anomalous 

 (!ambium advance more or less toward these openings and the 

 four ends of the normally oriented cambium left free by the 

 exit of the leaf-trace-bundles extend themselves inwards through 

 the openings in the ellipse, three of them finally efiecting a 

 union with the anomalous cambiums of the pith. The result 

 of this somewhat complicated process is represented in PI. XVIII 

 Fig. 4 where the complete continuity of the meristematic tis- 

 sue from c to c* etc. around arcs of more than 90° is shown. 



Such a relation between the normal and anomalous cam- 



1) Weiss, »Das markstandige Gefassbiindelsystem einiger Dikotyledonen in seiner 

 Beziehung zu den Blattspuren", pp. 14 — 19, Cassel , 1883. 

 Also Herail , 1. c. 



