Plate 15. 

 Ulva-composite. 



1. — Typical group of plants of Ulva Californica Wille, infested with Gnig- 

 nardia Ulvae Reed. (nat. size.) 



2. — Portion of surface view, showing "capsules" of cells of the Ulva sur- 

 rounded by the tips of the peripheral pigmented hyphee. (B. & 

 L., oc, 2, obj. 1/12.) 



3. — Cross section through the center of a perithecium. (B. & L. oe. 2, 

 obj. 1/2.) 



■i. — Three asci from a perithecium. (B. and L. oc. 2, obj. 1/12). 



.5. — Seven spores, ejected from a perithecium. (B. & L., oc. 2, obj. 1/12.) 



6. — Spores germinating in water. (B. & L. oe. 2, obj. 1/12.) 



Prasiola-composite. 



7. — Typical group of plants of Praslola horeaMs'Reed, infested hy Gu if/ >un-dia 

 Alaskana Reed. (nat. size.) 



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