MacDougaL — Symbiotic Saprophytism. 
47 
EXPLANATION OF FIGURES IN PLATES I 
AND II. 
Illustrating Prof. MacDougal’s Paper on Symbiotic Saprophytism. 
PLATE I. 
Fig. i. Typical specimen of Pterospora andromedea, actual height 80 cm. The 
apical flowers are unopened, while seeds have been matured in the basal ones. 
The entire system of roots is present. Drawn from a specimen collected by the 
author at Schultze’s Pass, San Francisco mountains, Arizona, August 3, 1898. 
Fig. 2. Young specimen of Pterospora, showing buds b, b, b at base of stem. 
The portion of the root-system cut away is indicated by the dotted outline. 
Fig. 3. Cross-section of root-system showing relation of roots to enclosed 
humus, x 20. 
PLATE II. 
Fig. 1. Mature specimen of Aplectrum developed from coralloid offset, m, 
coralloid offset or stem-mycorhiza. r, separatory layer of leaf. 
Fig. 2. Apex of coralloid formation (stem-mycorhiza) of Calypso, showing 
rudimentary leaves. After Lundstrom. 
Fig. 3. Apex of stem-mycorhiza of Calypso without leaves. After Lundstrom. 
Fig. 4. Diagram of the method of branching of the stem-mycorhiza of Calypso. 
After Lundstrom. 
Fig. 5. Diagram of the method of branching of root-mycorhiza of Pterospora. 
Fig. 6. Apical portion of rootlet of Pterospora showing the branches of the 
third order as conical projections. 
Fig. 7. Outer layers of root of Pterospora and mycelium : n. nucleus of 
epidermal cells; v. vesicular formation of Fungus. 
Fig. 8. Diagram of cross-section of Aplectrum with adhering tree-mycorhiza. 
Fig. 9. Aplectrwn. m. coralloid mycorhiza : s. scission layer. 
