MacDougaL — -Symbiotic Saprophytism. 23 
localities transmit the hyphae from internode to internode 
after the manner of Aplectrum , which would give opportunity 
for similar variation in the formation of the mycorhiza. 
Cypripedium parvifiorum (Salisb.). 
The roots are long wavy cylindrical organs 1 to 2 mm. in 
diameter, arising from the lower nodes of the upright stems. 
The epidermal cells are flattened cylindrical, with the outer 
walls yellowish and thickened. So far as the material 
examined shows, there are no root-hairs or papillose exten- 
sions of the walls. The exoderm is composed of irregularly- 
angled cells with thin walls. These two outer layers of cells 
are rich in protoplasm, some of which contain starch-grains, 
and others convoluted masses of colourless hyphae. 
The cortical cells are polygonal, with copiously perforate 
walls, and characteristically large nuclei. One or two of the 
outer layers contain a small number of cells with hyphal 
clumps, and the remainder of the tissue is very rich in starch. 
The central cylinder contains a relatively large cross-section 
of conducting tissue. The endodermis opposite the xylem-rays 
is composed of thin-walled passage-cells which do not become 
lignified even in old roots. The cell-walls opposite the 
phloem are evenly and heavily thickened to such an extent 
that the cavity is nearly obliterated. Slight traces of ligni- 
fi cation are noticeable. The Fungus does not gain access 
to the underground stem. The hyphal clumps are com- 
paratively few in number, and are small and irregular in 
shape. They are closely appressed to the nuclei, in which 
but little variation from the normal is shown. The relation 
here of the Fungus and the host-plant is quite an indifferent 
one. From the size of the chlorophyll-apparatus and the 
limited extent of the mycorhiza, it is to be inferred that 
the symbiotic saprophytism of the species is but little 
developed. 
