512 
R. J. HARVEY-GIBSON AND ELSIE HORSMAN ON 
Stems of the following have been examined, viz : — Lardizabala biternata, Ruiz 
and Pav., Holbcellia latifolia , Wall., Akebia quinata * Dec., and Decaisnea Fargesii, 
Franch. They all show marked differences from the Berberidacese, but many of 
these differences may be accounted for by their climbing habits. For instance, 
vessels of the xylem are much more numerous and have considerably larger lumina 
than any Berberidacese, while prosenchymatous fibres are very few, being replaced 
by xylem parenchyma which is often lignified and shows bordered pits with slit-like 
apertures. Thus the supporting tissue which predominates in woody Berberidacese 
is replaced in the Lardizabalacese by conductive elements. In common with many 
other climbers these plants show large sieve tubes. In Decaisnea the sieve plates 
occur on the bevelled ends, the polygonal sieve areas being separated by bands of 
cellulose, while sieve fields also occur on the lateral walls. Phloem fibres are absent, 
but on the external margins of the phloem areas are semi-lunar bands of sclerenchyma 
with very thick walls and packed with calcium oxalate crystals ; they appear to be 
of pericyclic origin and correspond to the ring in Berberidacese. The ring in this 
case, however, is much more irregular since the sclerenchyma is formed in depres- 
sions in the interfascicular regions, producing the ridged appearance so characteristic 
of lianes. 
The cork arises sub-epidermally and is normal in character. 
Akebia shows a well-marked endodermis, the cells being thickened on three sides 
and thin-walled on the inner, which abuts on the parenchyma. 
In many respects the Lardizabalacese appear to form a link between the 
Berberidaceae and the Menispermacese. 
The Lardizabalacese and Menispermacese consist chiefly of climbing shrubs, whilst 
the Berberidacese are not climbers. 
1. The cork in Lardizabalacese is sub-epidermal in origin, as also in some Berberi- 
dacese and Menispermacese. 
2. The pericyclic sclerenchyma occurs in arcs outside the phloem bundles, and 
since the bundles are close together, the arcs of sclerenchyma unite more or less into 
a ring. In this respect the Lardizabalacese differ from the Berberidacese, where the 
ring is continuous, and resemble the Menispermacese, which do not possess a con- 
tinuous ring but have sclerotic arcs round the vascular bundles connected by groups 
of stone cells. 
3. Bast fibres are absent from the phloem of Lardizabalacese and Menispermacese, 
but present in woody Berberidese. 
4. The xylem of Menispermacese consists chiefly of vessels with large lumina, and 
this is true also of Lardizabalacese, whilst in Berberidacese prosenchymatous fibres 
predominate. 
5. All three orders agree in having broad primary medullary rays. In all the 
non-herbaceous species of Berberidacese the medullary ray cells are well lignified. 
In some species of Lardizabalacese all the cells are strongly lignified, but in others 
