210 
Transactions of the Royal Society of South Africa. 
rather fantastically shaped (Fig. 4), and the larger specimens (Frontis- 
piece measure 6 in. or more across. 
Cutting through a young specimen longitudinally (Fig. 3), the peridium 
is seen to be composed of a number of peridiola (hence the name, from 
Greek polus, many, and saccus, a bag), and the following regions are 
distinguished : 
The young peridiola are a yellow ochre to grey chrome, and pass into 
Vandyke brown, which in the ripe peridiola becomes a raw umber separated 
by Vandyke brown walls. The peridiola are polyhedral, frequently elongated 
lengthwise, 4-6 x 2 mm., or 3 mm. across. They contain the basidia 
(Fig. 5), situated directly on mycelial cells and not forming hymenial layers. 
These basidia are pear-shaped (Fig. 6), and bear 2-6 spherical warty spores 
measuring 7"36-8"28 /x across. The peridiola ripen basipetally, the peridium 
splits irregularly, and on shaking the spores fall out as a dark powder. 
The fungal threads (Fig. 7) forming the walls of the peridiola are inter- 
twined, and the walls 62'5-150 /x thick, chrome yellow or Vandyke brown. In 
small specimens the stalk may only be represented by a sterile Vandyke 
brown region with yellowish cavities at the base of the peridium, but it may 
attain dimensions 6-17 cm. long x 5-10 cm. across. In fresh specimens the 
interior of the stalk is indiarubbery in consistency, but old stalks left 
standing in the field become extremely hard and woody. The interior varies 
in colour from yellow to a yellowish-brown, and whereas the part above the 
soil is externally a dark brown, that below is usually yellowish. The 
yellowish cavities mentioned above are sterile peridiola (Fig. 8), and appear 
also along the peridial wall, which they serve to strengthen. The rhizo- 
morphic threads are 5*3 mm. (seldom 1 cm.) across; the ends are thinner, 
ramify through the soil, and intertwine themselves between the soil particles 
much as root hairs do. The thicker strands are frequently flattened in 
contact with hard pieces of soil, and from them pass the thinner strands 
referred to. These rhizomorphic threads Ijecome adherent to old vegetable 
debris, are abundant to a depth of 1-2 in. below the soil, and even occur as 
far as 3 in. down. The thicker strands are of yellow ochre, but the thinner 
ramifications more of a dark brown. 
A section through one of the thicker shows one or more aggregations of 
a few thick- walled cells, which evidently serve the purpose of conduction. 
Kelation of the Fungus to the Eucalyptus. 
The fungus forms chrome yellowish masses (Figs. 9-11) over the thicker 
roots of the trees, and the thinner are at times covered in places by a coating 
of the fungus, from which pass the threads already referred to. Again, the 
threads running over the surface of roots become in places attached. 
A section through a root shows the yellowish fungus threads between the 
cork cells. These mycelial cells are frequently only -435 /x across, and later 
