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MISS NELLIE BANCEOET ON 



the normal part of stele 5 very closely. It is impossible to say wtether the two steles 

 5 and 6 are really distinct, for the appearances almost suggest an anastomosis between 

 them. In stele 6, as in 5, the elements are mostly oblique in direction. 



Stele 7 is more suggestive of a complete stele than any of the others shown in 

 Section A. The break in continuity of development at the left-hand side is very slight, 

 the chief evidence of it being a confusion of direction of the xylem elements here 

 (PL 10. fig. 5). It seems as if the outer and inner cambiums had almost joined at 

 this point. At the right-hand side, however, where a trace is evidently about to separate 

 from the inner mass, separation of the normal and inverse parts is very distinct. 

 As usual, the structure of the tissues external to the xylem and between the two 

 groups is obliterated. The transverse section from the opposite end of the stem- 

 fragment includes only a small portion of this stele; its straight course, indicating 

 but slight change of position or form, is shown by the vertical cut surface figured 



in PL 10. fig. 13. 



The other steks of the inner series, as 



shown in Section A, do not present any 



points of structure (see diagrams of steles 8 and 9, PL 10. figs. 6 & 7). In Section B, 

 stele 9 shows the same outlines as in the filrst, 7 and 8 are incompletely represented, but 



o 



T 



ht course and unbroken contours are shown in the diagram (PL 10. fi 



The position of steles 6, 7, 8, 9, and 10 ia Section B appears slightly closed in towards the 

 interior of the stem as compared with their position in Section A {cf. PL 11. figs. 7 & 8). 

 Stele 10 is complete in Section B. It is much smaller than the others, consisting of a 

 comparatively large, fan-shaped, inversely orientated part and a very small normal part. 

 There is a slight indication of a partial pith, and both parts of the stele possess much of 

 the brown phloem-like tissue (PL 11. figs. 7 & 4), 



Immediately external to the inner steles, at the periphery of the stem-fragment, are 

 several portions of large masses of normally orientated xylem (PL 10. fig. 1 ; PL 11. 

 figs. 7 & 8, a-ff)j representing presumably a second series of steles. They are evidently 



product of independent cambiums, which, so far as can be judged from the form of 



the incomplete masses, must have had a more or less arched course, as in the case of the 

 cambiums of the inner series of steles. The first-formed xylem elements of these masses 

 are sometimes almost in contact with the inner steles ; in every case the ground-tissue 

 between the two series of vascular structures is crushed. 



The members of the second series of xylem groups correspond to the small parts of 

 the inner ring, having no inversely orientated groups pairing with them. They are 

 thus, in terms of the inner series, " partial steles." Partial steles c, d, and e, as seen in 

 Section A, show breaks in the xylem, the medullary rays and radial series of elements 

 being discontinuous along certain lines, although the general direction of development 

 remains the same after the break as before (PL 10. fig. 3j. This indicates a cessation of 

 cambial activity for a time ; or a new cambium may actually have arisen. 



In association with the majority of these partial steles are patches and strands of 

 xylem elements. In the case of 5 a large strand is seen in actual connection ; but their 

 nature, and in most cases their origin also, is extremely problematical. They may be 

 developed by abnormal extensions of the cambium, or they may be ultimately connected 



