510 
R. J. HARVEY-GIBSON AND ELSIE HORSMAN ON 
lateral plates and companion cells ; as in P. peltatum, no fibres and no parenchyma 
are present. 
The material examined was herbaceous and no cork was noticeable, although it is 
given by Solereder as sub-epidermal in origin. 
The rhizome shows a distinct ring of large bundles, with a few smaller ones 
outside in the cortex, but the arrangement is not as definite as "in Achlys. There is 
no peripheral ring of pericyclic fibres such as is shown by the rhizome. In the main 
bundles the xylem consists of a few scalariform tracheids, wide vessels showing a 
variety of markings — spiral, loosely reticulate, long oval pits, and bordered slits, — 
and many parenchyma cells showing no lignification. The phloem is very little 
differentiated and consists of radially arranged elements, a few of which are sieve 
tubes, while most seem to be parenchymatous in their nature. The tissue bordering 
on both phloem and protoxylem consists of smaller cells which are slightly sclerotic, 
with simple pits in their walls. The central parenchyma cells, which are slightly 
elongated, contain resin. 
The petiole resembles the aerial stem in having a ring of bundles towards the 
periphery and irregularly scattered bundles in the centre, formed from the bundles 
nearest the upper surface of the leaf. 
Diphylleia cymosa, Michx., is very similar to Podophyllum in anatomical 
structure. In the aerial region there is the same ring of sclerenchyma towards 
the periphery and a ring of bundles with their phloems partly embedded in the 
sclerenchyma. The other vascular bundles are scattered irregularly, as in Podo- 
phyllum, and have sclerenchyma on the outer margins of their phloems. The 
phloem and xylem elements, as also the anatomy of the rhizome and petiole, agree 
with the description given for Podophyllum. 
The chief characteristics of the stem of the Podophylleee : — 
1. The' bundles are scattered, the larger being towards the centre, as in Mono- 
cotyledonous stems, while the outer and smaller bundles have their phloems embedded 
in a sclerotic ring. 
2. In the aerial axes the main bundles are in the form of a ring with smaller ones 
more peripherally placed. 
3. The xylem consists chiefly of vessels with annular, reticulate, and scalariform 
thickenings and long, oval bordered pits. 
4. No prosenchymatous fibres were found, but unlignified parenchyma cells are 
present among the vessels. 
5. The central parenchyma is practically homogeneous, although a few cells near 
the protoxylems are slightly sclerotic. 
In comparing the stem anatomy of the Berberidese, Epimedese, and Podophyllese 
it may be noted — 
1. Thai all three subdivisions are characterised by possessing a ring of pericyclic 
sclerotic fibres in their aerial stems. 
