1893.] 
Root Tubercles of Leguminose. 791 
EXPLANATION OF PLATES.. 
A. Longitudinal section of a mature tubercle of Melilotus alba. 
a. Cork layer. 
b. Phellogen. 
c. Vascular bundle in longitudinal section. 
d. Infected area showing the Rhizobia radiating from the 
nucleus as a centre. 
e. Vascular bundle, cross section. 
f. Apex of cambium layer. 
h. Starch layer next to infected area. 
i. Rhizobium mutabile of Melilotus alba as seen in the early 
part of November. 
j. Calcium oxalate crystals. 
k. Parenchymatous tissue continuous with that of the 
root. 
r. Noninfected cells in the infected area bearing starch. 
B. Cross section of a tubercle of Phaseolus vulgaris. 
a. Cork layer consisting of rounded cells. 
b. Phellogen. 
c. Lenticels. 
d. Infected area, Rhizobia are arranged in zoogloeae. 
e. Vascular bundles, all in cross section. 
g. Calcium oxalate crystals. 
i. Rhizobium frankii var. majus from bean tubercle. 
j Normal nucleoli. 1. Nuclear wall. 3. Nucleoli 4. 
Nucleoplasm. 
k. Much modified nuclei form infected area. 1. Nuclear 
membrane. 2. Processes of the nucleoplasm. 3. 
Nueleoli. 4. Nucleoplasm. 
C. Details. 
l. 
Small portion of tubercle of Trifolium pratense invaded 
by the “Infektions fäden” (Schinzia leguminosorum). a. 
Hyphe of the fungus. b. Enlargements next to cell wall. c. 
* Haustoria." 
