AFFINITIES OF BALANOPHOREÆ. 11 
the lobes of which project outwards as the bases of the medullary rays ; and between these 
lobes lie the axial ends of the vascular wedges. The following is a summary of these 
characters :—1. The axis is occupied by hexagonal cells, which become vertically elon- 
gated and woody (see 2.) towards the vascular wedges, and then radially elongated in the 
medullary rays, and pass insensibly into the membranous hexagonal tissue of the cortical - 
portion: these cells contain grains of starch, and chlorophyll in abundance. 2. The 
woody tubes forming the outer zone of the axis (which is in many respects analogous to 
a medullary sheath) consist of long and strong cylindrical pleurenchyma, with much- 
elongated angular sclerogen-cells: these are all extremely hard, and their walls are per- 
forated by innumerable canals. In old specimens the pith passes gradually into these 
tissues; its utricles becoming first cubical, with thick dotted or perforated walls; then 
becoming tubes elongated vertically ; which are succeeded by tubes with blunt ends and 
narrow cavities. 3. The wood consists wholly of scalariform vessels which are cylin- 
drical in young rhizomes, but polygonal with transversely barred or gashed walls in older 
ones; intermixed in every instance with smaller, more irregular and variously marked 
or perforated cells and tubes. 4. The liber-bundles consist of large, stout-walled, woody, 
hexagonal tubes, of great density ; their walls everywhere perforated by canals. 5. The 
isolated sclerogen-cells in the cortical portion in no respect but shortness differ from liber. 
Both in arrangement and in anatomical characters this description of the rhizome re- 
sembles in most particulars that of the stems of many Menispermee ; and a more close 
examination bears out this resemblance. 
- In a transverse section of the peduncle of Helosis mexicana (Plate XV. fig. 12), eight 
symmetrically disposed vascular bundles are seen, and outside of these a few smaller 
irregularly scattered ones: and, as in Balanophora, the anatomical structure of the ves- 
sels composing these differs from that of the rhizome only in degree. The bundles consist 
of a sheath of elongated cellular tissue, enclosing a few fusiform vessels, some scalariform, 
others with spiral bands or transverse bars, with a few woody tubes and sclerogen-cells ; 
and these may be traced up to the scales of the capitulum, to which scales much stronger 
bundles are given off than to the flowers. 
- In the rhizome of Helosis guyanensis (Plate XVI. fig. 80) I find—1. The whole pith 
torpid of the same woody vessels as surround the pith of H. mexicana; and this both in 
New Grenada, Trinidad, and Rio de Janeiro specimens; these pass into a muriform tissue 
of woody tabular cells, which occupy the broad medullary rays, and of polyhedral cells 
still with very thick walls, in the circumference of the rhizome. 2. The wood is seen in 
a transverse section to be formed of seven lanceolate wedges of soft, white, scalariform, 
or spirally unrollable tubes. 3. A very large reniform mass of liber-cells or short tubes _ 
is placed outside each wood-bundle, and in contact with it. This does not seem to in- 
crease annually, but other and equally large liber-bundles form a zone exterior to these, 
and alternate with them; as in many Menispermeæ. 4. Isolated masses of sclerogen- 
cells and long liber-vessels are scattered throughout the parenchyma of the periphery. — — 
The peduncle of Helosis guyanensis presents innumerable bundles of vascular tissue, 
composed of sclerogen-cells, spirally marked and scalariform vessels, and a few woody tubes, 
generally occupying definite relative pe In a specimen of H. guyanensis from 
c2 
