KNOWLEDGE OF MONOCOTYLEDONOUS SAPROPHYTES. 165 
increase in the elements of the xylem. Each bundle has a 
large group of wide tracheides, and protoxylem in the form of 
spiral vessels. The phloém, too, is well developed, and consists 
of sieve-tubes, companion-cells, and parenchyma. The vascular 
bundles are embedded in lignified parenchyma. Towards the 
attachment of the buds and of the inflorescence-axis, the lignifi- 
cation of the ground-tissue diminishes. 
Structure of the Flowering Axis. 
In my specimen there was only one flowering axis, five inches 
in length, and bearing three large fruits. From its base adven- 
titious roots arise. The scale-leaves aré attached close together 
at the base, but higher up they dwindle in size and are separated 
by longer internodes. 
Taking sections about halfway up this axis, the structure 
revealed is as follows :— 
1. Epidermis composed of narrow cells much elongated longi- 
tudinally, with thick heavily cuticularized outer walls. The 
cuticularization is continued into the lateral walls. No stomata 
occur. Even at this height, pegs similar to those formed by 
mycorhizal hyphe in the root and rhizome are found. 
2. Cortex made up of cells elongated longitudinally. Exter- 
nally are a number of layers of collenchymatous cells with small 
intercellular spaces. Travelling inwards from the epidermis, the 
collenchymatous thickenings diminish and the intercellular spaces 
increase in size, but are small at their maximum. Then succeeds 
a general sheath composed of several layers of sclerenchymatous 
fibres, with small lumina and with very small intercellular spaces. 
No thin-walled cells interrupt this sheath. 
3. Embedded in this sheath and lying in the stelar parenchyma 
are numerous vascular bundles. 
There is only a small central mass of parenchyma free from 
bundles. No starch occurs. Only a few isolated mucilage-cells 
are present, so that transverse sections may be taken in which 
no mucilage-cells are visible. 
Structure of the Vascular Bundles (Pl. IV. fig. 3).—Each 
bundle is collateral and has a sheath of sclerenchymatous fibres 
round it. 
The phloém consists of sieve-tubes with terminal and oblique 
Sieve-areas, long companion-cells with elongated narrow nuclei, 
LINN, JOURN.—BOTANY, VOL. XXXI. N 
