102 



MISS NELLIE BAN'CEOFT OlS 



EXPLANATION OP THE PLATES. 



Plate 10. 



Figures 1-12 diagraramatiCj figures 14-18 drawn with the aid of a camera lucida. 



Fig. 1. 



Transverse surface of the stem, after cutting, showing the main features {cf. PL 11. fig. 8^ 

 a photograph of the complete Section A, taken from this surface, and representing a level 

 slightly higher in the stem) : l-13j steles of the inner series ; a~g^ partial steles of the outer 



series. Nat. size. 



Figs. 2-8. Transverse sections of the vascular structures of the stem^ drawn from the complete 



Section A^ shown in PL 11. fig. 8. Comparison should be made with this and with fig. 1 

 for the relative positions of the vascular masses of the stem, tr signifies transverse section 

 of the xylem elements ; oi, oblique section ; and Iffy longitudinal section. The shaded out- 

 lining of the steles indicates the brown crushed tissue. 



Fig, 2, stele 3 of the inner series ; jgm, partial pith ; px^ protoxylem ; at oi a trace is seen 

 separating from the larger inverse part of the stele. Fig- 3, steles 4 and 5 of the inner 

 series, and partial steles c and d of the outer series : a and ^^ normal and inverse xylem^ 

 respectively, of the inner steles ; 7, xylem evidently belonging to y3, but more or less 

 separated from it by breaks in the continuity of the radial series of elements : similar 

 breaks are seen in partial stele c ; Sy sclerotic nests. Figs. 4, 5, and 6, steles 6, 7, and 8, 

 respectively. Fig. 7, stele 9, showing sclerotic nests in the crushed tissue at s. Fig. 8, 

 central stele ; pd, bands of periderm. Figs. 2-7, x3 ; fig. 8, X 5. 



Fig. 9. Central stele, at a slightly higher level than fig. 8. (From an incomplete Section.) x5. 



Fio"s. lO&ll. Vascular structures at the level of Section B, shown in PI. 11. fig. 7. Fig. 10, steles 5 



and 6 of the inner series, and partial steles d and e of the outer series : vb^ isolated and 

 irregular vascular strands ; other lettering as before, x 3. {Cf. figs, o & 4.) Fig. 11, central 

 stele : wy^, xylem elements enclosed in periderm ; /ry^^ xylem elements scattered in ground- 

 mass, x 5. (Cf. figs. 8 & 9.) For the position of the central stele as shown in figs. 8, 9j 

 & 11, relative to that of the other vascular structures of the stem, refer to fig. 1 and PL 11. 



figs. 7 & 8. 

 Fig. 12. Diagram showing the relation between the vertically striated bands of the outer surface of the 



stem (c/. PL 11. fig. 1) and the vascular masses of the cut transverse surface. Kat. size. 

 Fig. 13. Portion of a tangential longitudinal surface, showing the straight course of two inner steles 



(7 and 8) : a, ground-mass. Nat. size. 

 Fig. 14. Xylem elements, showing the layered siliceous filling of the cell-cavities (see also figs. 15 



& 18). Kote indication of middle lamella, ml. x450. 

 Fig. 15. Protoxylem group of stele 3 {cf fig. 2). X 450. 



Fig. 16. Sclerotic nests in the crushed tissue of stele 9. x 90. {Cf fig. 7, s, and PL 11, fig, 4.) 

 Fig. 17. Pitting of the tracheides : a, typical ; i, from the limb of the central stele, x 280. {Cf PL 11. 



fig- 5.) 

 Fig. 18, Tangential section of xylem, showing the uniseriate medullary rays. Note the layering of 



siliceous material in the cells of the rays, x 280. 



