THE ANATOMY OF THE STEM OF THE BERBE RIDACE2E. 
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the cells in. the centre of the rays are thin- walled, flanked by sclerotic cells. 
The Menispermacese agree with the Lardizabalacese in often having unlignified 
medullary rays. 
Berberidopsis. — Hallier describes Berberidopsis as a syncarpous Berberis with 
points in common with the Flacourtiacese, while Engler and Prantl and Bentham 
and Hooker place it definitely in the Flacourtiacese. 
An examination of the stem structure of Berberidopsis corallina, Hook., presents 
the following characters (fig. 15) : — 
1. A thick cuticle is present on the epidermal cells. 
2. The external cortex often contains stellate crystals of calcium oxalate. 
3. The ring of sclerenchyma is very open and is interrupted in older stems. The 
cells are short and rectangular and have numerous simple pits in their thick walls 
(figs. 16, 17). These sclereides correspond to the stone cells in the cortex of young 
twigs of Acer and iEsculus, but in these two genera the sclereides accompany 
sclerenchymatous fibres, the latter being much more numerous, whereas in Berberi- 
dopsis the sclereides predominate and very few fibres occur. Haberlandt (ll) 
suggests that these sclereides are cortical parenchyma cells which have penetrated 
gaps produced in the mechanical cylinder of bast fibres as a result of tensions set up 
by the growth in thickness of the twigs. The cortical parenchyma cells afterwards 
become thick-walled and so restore the unity of the now composite mechanical 
cylinder. The varied shape and arrangement of the sclereides seem to support 
this view. 
4. The cork arises sub-epidermally and is normal in character, the cells being 
rectangular. 
5. The xylem contrasts markedly with that of Berberis, the elements are larger, 
and the main portion consists of large vessels which are slightly thickened and have 
very loose reticulations forming large irregular pits (fig. 18). Tracheids are present 
with oval bordered pits. 
6. Most of the cortical cells are thin-walled, but a few near the protoxylems are 
sclerotic, and all of them* show simple pits. The more peripheral cells often contain 
starch grains or crystals of calcium oxalate. 
7. No bast fibres are present in the phloem. The information available as to 
the anatomy of the Flacourtiacese is at present very meagre, so that a detailed com- 
parison with the Berberidacese is not possible. The following points of resemblance 
may, however, be noted : — 
1. In the Flacourtiacese the sclerotic ring may be continuous, or in patches 
joined by bridges or broken up completely into islands. 
2. In both the xylem shows wide reticulate thickenings. 
3. The medullary rays are numerous and vary from one to four cells in width in 
both families, but in Berberidacese the rays are wider and less numerous. 
