a New Genus of P lasmodiophoraceae. 
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EXPLANATION OF PLATE XLV. 
Illustrating Messrs. Ferdinandsen and Winge’s paper on Ostenfeldiella, a New Genus of 
Plasmodiophoraceae. 
The figures are all microphotographs. 
Fig. 1. Part of a median, longitudinal section just below the growing apex of a Diplanthera 
stem infected with Ostenfeldiella Diplantherae. Cf. Text-fig. 4. To the left the central cylinder; 
to the right the inner cortex, where the small amoebae of the parasite are to be seen, x 600. 
Fig. 2. Longitudinal section on the limit between the second and the third internode (from the 
apex) of an infected Diplanthera stem. In the second internode (above) are seen only plurinucleate 
myxoplasms, whereas in the third internode (below) sporogenous plasms and spore masses have been 
developed, x 40. 
Fig. 3. Part of a longitudinal section through an infected Diplanthera stem. Giant cells from 
the inner cortex with sporogenous plasms or spore masses. The nuclei of the host plant are about 
to be dissolved. To the left the unaffected cells of the outer cortex with starch grains, x 325. 
Fig. 4. Part of a transverse section through the infected Diplanthera stem. The giant cells of 
the inner cortex are filled with spore masses of Ostenfeldiella (in some cells dropped out), whereas the 
central cylinder, as well as the outer cortex and the epidermis, is free from the parasite, x 50. 
Fig. 5. Mature spores of Ostenfeldiella Diplantherae , partly collapsed from the action of the 
fixing agent, 90 per cent, alcohol, x 950. 
