Notes on the Sori of Macrocystis and Postelsia. 87 



EXPLANATION OF PLATE XX. 



Fig. i. Macrocystis pyrifera. Trans, section of frond (x 10). 



Fig. 2. Trans, section of a furrow of the fertile frond 



(x 66). 



Fig. 3. Sporangia and paraphyses ( x 450). 



Fig. 4. Postelsia palmaformis, Trans, section of frond ( x 10). 



Fig. 5. ,, Trans, section of a furrow of the frond ( x 50). 



Fig. 6. Sporangia and paraphyses ( x 440). 



N 



