626 
Spratt .— The Root-Nodules of the Cycadaceae . 
Fig. 6. Root-nodules of Macrozamia Macleyi. Nat. size. 
Fig. 7. Root-nodules of Ceratozamia mexicana. Nat. size. 
Fig. 8. Root-nodules of Dioon spinulosum (a) spherical masses and large swollen tip; ( b ) with 
algal zone present. Nat. size. 
Fig. 9. Part of longitudinal section of nodule of Encephalartos without an algal zone, 
x 70. 
Fig. 10. Portion of the algal zone of the nodule of Encephalartos . p. = papillate cells. 
n. = nucleus, x 325. 
Fig. 11. Part of longitudinal section of nodule of Encephalartos with an algal zone, g . = gap 
in algal zone by lenticel; E. — end of algal zone. A. Z. algal zone, x 35. 
Fig. 12. Part of longitudinal section of nodule of Stangeria showing the basal ridge of 
tissue — b.r. x 35. 
Fig. 13. Portion of a longitudinal section of nodule of Stangeria with enclosed areas of Bacteria 
and Algae, x 70. 
Fig. 14. Part of longitudinal section of root and nodule of Dioon, showing mass of fan-shaped 
parenchyma = b. at base of nodule; m. = meristematic tissue ; t. = tannin, x 35. 
