(423 ) 
ately behind the calyptrogen and may not be distinguished in 
Monotropa except by their position, and these regions in /y- 
popilys as well, do not become differentiated until some dis- 
tanc> back from the tip (Plate 11, Fig. 10). The pressure 
of the mycelial mantle and the crushing of the outer cells of 
the root cap gives rise to displacements of the initial elements 
in a radial direction. 
The stele is much reduced in all members of the family. 
Oliver notes that five xylem bundles are to be seen in Sar- 
codes, although our material showed six; three or four appear 
in Hypopitys according to Kamienski, but no exact statement 
may be made as to Afonotropa. Pterospora and Sarcodes 
exhibit five or six bundles of protoxylem surrounding a cen- 
tral medulla. ‘That of Sarcodes shows spiral vessels and 
scalariform ducts, but Prerospora has but three or four scali- 
form vessels in each bundle. Kamienski notes the presence of 
vessels half way between spiral and the annular form in //y- 
popitys, as well as sieve tubes, bast and wood cells. The 
phloem in all of the species appears to consist chiefly of elon- 
gated elements much like companion cells. The central cyl- 
inder of Afonotropa shows the greatest reduction of any seed 
plant which has yet been noticed. The xylem bundles at no 
time are distinct, but their remnants are crowded to the center 
and make a cluster of four or five scalariform vessels, five or 
six times as long as broad with oval perforations, obliquely 
placed (Plate 11, Fig. 5 and 7). The ends do not open into 
each other. Surrounding these vessels is an irregular circle 
of elements of slightly smaller dimensions and heavy protein- 
aceous content (Plate 11, Fig. 5). No endodermis may be 
made out. The cortex consists of seven to ten layers of glob- 
ular or cylindrical cells, which sometimes show much starch 
especially near the tips of the root. 
The epidermis is composed of columnar cells in Sarcodes 
and ovoid elements in the other genera. These cells are in 
contact with each other near the apex of the root but soon 
become separated by the hyphae which push in between, 
making a pseudo-parenchyma (Plate 12, Fig. 15). The 
