PLATE IX. 



Nitella spanioclema Groves & Bullock-Webster. 



FIG. 



1, 2. Plant, natural size, from Lough Shannagh, West Donegal. 



3, 4. Branches with branchlets showing short, solitary and 

 rudimentary secondary rays, and conspicuous scars 

 left by fallen antheridia and oogonia. x c. 10. 



5. Oogonium. x c. 30. 



6. Oospore. x c. 30. 



7. Membrane showing wart-like protuberances and minute 



granular decoration. x c. 200. 



8. Portion of membrane showing disposition of granules. 



x c. 800. 



