240 МВ. W. FAWCETT ON А NEW SPECIES ОҒ THONNINGIA. 
Burmeisteri" *, has shown that in its 4- or 5-sided rhizome there are four or five central 
bundles with normal orientation, and that near each angle in a transverse section there 
are several small bundles arranged on each side of an imaginary line joining the angle 
with the centre, in such a way that the bundles are placed sideways as regards the centre, 
with the xylem facing the imaginary line. But an opposite orientation, even more 
pronounced than in Thonningia, because repeated, occurs in the rhizome of Nelwmbium 
speciosum, in which there are several concentric circles of bundles, the first and second 
of which nearest the centre are normal; the third is opposite, the fourth is normal, and 
the fifth isagain opposite. Another example occurs in the cortical bundles of Calycanthus 
occidentalis. 
The parenchyma of the rhizome is composed of cells which are twice or thrice longer 
than wide. Towards the periphery the cells become smaller, and are of the same 
diameter longitudinally as transversely. The epidermis is composed of irregular 
projecting cells, as in Lengsdorffia. The hairs are a millimetre or more in length, 
composed of two cells, the basal one short and somewhat bulbous, the other long and 
slender. The cell-wall of the hairs is covered with very minute granular warts. 
Several of the cells have their walls so much thickened that the central cavity has the 
appearance of a long pore from which very numerous branching pores pass off to the 
periphery. These sclerenchymatous cells (** stone-cells," as the Germans call them) are 
longer and somewhat broader than the ordinary cells; they occur in masses, running in 
longitudinal strands parallel with the fibro-vascular bundles. In Langsdorffia the part 
of the cell-wall which is in contact with the soft-walled parenchymatous cells remains 
unchanged; this is not so evident in Thonningia, since the cavity of the cell is extremely 
narrow, but it also occurs, and then the pores appear almost as if they originated on the 
cell-wall. 
The axis of the rhizome is occupied by one of these sclerenchymatous strands of an 
elliptical outline in transverse section, and of so great a diameter that it is easily recog- 
nized by the naked eye. The cambium-layer of the four internal fibro-vascular bundles 
is fairly parallel with the long axis of the elliptical outline, which is vertical, the shorter 
axis being horizontal. Sometimes the cells in the centre of this axial strand have walls 
which are only half the thickness of those that occur elsewhere ; sometimes the upper 
and lower parts of the strand are entirely separated by a band of the ordinary parenchy- 
matous cells. The outer cells are occasionally compressed in a radial direction. It is 
interesting to trace the resemblance with Helosis, which has a greater differentiation of 
this axial strand, so much so that Eichler + speaks of the medulla and the rays. It is in 
this respect very much nearer Helosis than Langsdorffia. 
There are no sclerenchymatous strands corresponding in position to those which in 
Helosis are situated outside each fibro-vascular bundle, with a cup-like form in trans- 
verse section. They occur arranged somewhat concentrically, but still irregularly, 
gradually decreasing in diameter and in the number of cells to the periphery. 
* A. F. W. Schimper in Abh. der Natur. Gesell. zu Halle, 1880. 
+ Mart. Fl. Bras. fasc. 47, Balanophore:e, p. 25. 
