. Algæ. Vol. I. Myxophyceæ, Peridinieæ, Bacillarieæ, Chlorophyceæ, together with a brief summary of the occurrence and distribution of freshwat4er Algæ . Fig. 22. Part of a transverse section of tubercle-like root of Ci/ciis showing the algal zone ()containing Anab&na Cycadearum Eeinke and certain Bacteria, c., cork; , outer cortex;, inner cortex, x 400 (modified from Spratt). peculiar environment have not yet been investigated. Another occursin the stems of Gunnera. Hugo Fischer (04) has described a symbiotic relationship betweencertain of the Oscillatoriaceae which carp

---

. Algæ. Vol. I. Myxophyceæ, Peridinieæ, Bacillarieæ, Chlorophyceæ, together with a brief summary of the occurrence and distribution of freshwat4er Algæ . Fig. 22. Part of a transverse section of tubercle-like root of Ci/ciis showing the algal zone ()containing Anab&na Cycadearum Eeinke and certain Bacteria, c., cork; , outer cortex;, inner cortex, x 400 (modified from Spratt). peculiar environment have not yet been investigated. Another occursin the stems of Gunnera. Hugo Fischer (04) has described a symbiotic relationship betweencertain of the Oscillatoriaceae which carpet the ground (such as Phormidiumautumnale) and Azotobacter Chroococcum. The nitrogen-fixing activity ofthe Bacterium enables the Blue-green Alga to make use of atmosphericnitrogen. A still more remarka,ble member of the Nostocacete is Richelia intra-cellularis Johs. Schmidt, which lives within the cells of marine species ofRhizosolenia (fig. 23). As this Alga occurs within the living cells of thehost it may be assumed that it is a partial parasite. Helot-ism.

---

Size: 978px × 2555px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No

Keywords: ., bookcentury1900, bookdecade1910, bookpublishercambridgeengtheuni