210 DR J. M. MACFARLANE ON THE 



'. Lapageria Root. — Transverse sections of the root of 1 (Plate I. fig. 3) show that the epidermis 



t. Phiiageria s00n ruptures, and is destroyed by abrasion or is shed in patches. Where tracts of it 

 >•. Phiiesia buxi- are l e ft like the one seen in the figure, the cells are equilateral or columnar in outline with 

 more or less rounded angles, and measure 40 /x across. A considerable degree of variability 

 is shown in the outline of these, and this is in striking contrast with corresponding cells 

 of 3, which are very uniform. As might be expected from its duration, and as is proved 

 when soft young roots are examined, the cuticular layer is always thin. The epidermis of 

 3 is strongly persistent (Plate I. fig. l), and is made up of cells which are one and a half 

 to two and a half times broader than deep, measuring 80 by 60 /x on the average. Each 

 has a very thick cuticle on its outer face, which is continued as a thinner layer inwards 

 between adjoining cells, and the cuticular lamellae are very evident. Large unthickened 

 areas, with pore apertures, occur over the transverse partitions. In 2 the epidermis (Plate 

 I. fig. 2) persists well on the whole, though here and there one finds areas over which 

 rupture and decay of cells has begun. Each cell is from equilateral to columnar, but 

 considerable variability is shown, thus the cells in the figure are slightly columnar, but 

 others in my possession are decidedly more like those of 3. But a very constant feature 

 is the amount and disposition of cuticular substance. As shown by comparison of 

 figs. 6, 5, and 4, the amount is about half of the parent extremes, and is thickest externally, 

 thinning out round the sides. On the transverse partitions are unthickened areas 

 that show smaller and more minute pores than in 3. 



The outer cortex of 1 (fig. 6), to the extent of eight to ten layers, is greatly thickened 

 in its elements, by sclerenchyma deposits, of which the external three or four zones are 

 smaller in size and more thickened in their walls than those internal. The latter pass, 

 by a pretty gradual transition, into the large-celled parenchyma of the inner cortex. 

 The average size of the sclerenchyma elements is 20 /*-. In 3 the outer cortex (fig. 4) 

 is strongly thickened only in the sub-epidermal cell layer, each element of which has a 

 greater amount of thickening over its outer than over its lateral faces, and measures 60 \i. 

 across. Beneath this are one or two layers very feebly thickened and smaller than the 

 last (40 to 50 m), which are demarcated abruptly from the thin-walled large-celled paren- 

 chyma. In 2 (fig. 5) four to five layers are thickened, and of these the external one is 

 made up of rather larger cells which show a greater thickening of their outer than of their 

 lateral walls. The cells measure 32 to 35 /a across, and are continuous, by a row of transi- 

 tion cells, with the inner large-celled parenchyma. 



The inner cortex of 1 is a cylinder of twenty to twenty-five cell layers, the average size 

 of the elements being 45 to 50 /x. The two or three innermost layers next to the bundle- 

 sheath are shallow and flattened. That of 3 is a cylinder of eight to nine open loose- 

 looking cell layers, the cells of which are 100 to 120 /x across. Only the innermost layer 

 may be slightly smaller but not flattened. In 2 the cylinder consists of fifteen to seven- 

 teen layers whose elements are 70 to 75 /a ; the innermost layers are flattened, and the 

 one external to it smaller in its cells than those of the general cortex. 



The bundle-sheath is of considerable interest. In 1 (Plate I. fig. 9) it consists of small 



