HOWE AND HOYT: MARINE ALGAE FROM BEAUFORT, N. C. 121 



Explanation of plates 11-15 



Plate ii 

 1-9. Phaeostroma pusillum 



1. Margin of thalliis, 'showing discrete repent filaments, plurilocular sporangia, 

 hair, etc. 



2. Enlarged detail, showing immature plurilocular sporangium, chromatophores, etc. 



3. A mature plurilocular sporangium in obliquely longitudinal view. 



4. A mature plurilocular sporangium viewed from above (end view). 



5. Margin of thallus (more compact than that shown in Fig. i), with unilocular 

 sporangia. A sorus at a and the beginning of a sorus at b. 



6. Enlarged detail of thallus, showing chromatophores and unilocular sporangia 

 as seen from above. 



7. A young unilocular sporangium, viewed from above. 



8. The beginning of a sorus, viewed from above. 



9. A mature sorus of unilocular sporangia, viewed from above. 



Figures I and 5 are enlarged 245 diameters; 3 and 4, 670 diameters; 2, 6, and 7-9, 

 1040 diameters. 



10-16. Derbesia turbinata 



10. Apex of thallus, showing a young lateral branch. 



11. Lateral branching, or "unequal dichotomy." 



12. A dichotomy of thallus. 



13-16. Usual forms of sporangia. Fig. 13 shows a short pedicel cell; 15, a longer 

 one; in 14 and 16, no septa have appeared. 



Figures 10-12 are enlarged 81 diameters; 13-16, 162 diameters. 



Plate 12 

 1-5. Erythrodadia recondita 



I. Portion of thallus near margin, viewed from above, showing outlines of proto- 

 plasts and of pyrenoids and also outlines of the cortical cells of its host. 



2 and 3. Portions of cross sections of the endophyte and its host, showing the more 

 or less exserted spermatia (spm) and the immersed vegetative cells. 



4. Portion of a cross section, showing a carpogonium with exserted trichcg>'ne. 



5. Portion of pseudoparenchymatous thallus, viewed from above, showing proto- 

 plasts of vegetative cells, spermatia {spm), carpogonium {cpg), and sporocarps {spcp ). 



Figures are all enlarged 670 diameters. 



6-1 1 . Erythrodadia vagabmida 



6. Portion of thallus, viewed from above, showing outlines of protoplasts and pyre- 

 noids and also outlines of the cortical cells of its host. The cells, here enlarged 415 

 diameters, appear of about the same size as those of E. recondita when enlarged 670 

 diameters (Fig. i). 



7. Portion of thallus, showing three vegetative cells, six sporocarps {spcp), and five 

 cavities from which carpospores have been discharged. 



8 and 9. Portions of thalli, showing vegetative cells and sporocarps {spcp). 

 10. A single carpospore lying on the surface of its host, in the outer walls of which 

 it is already partially immersed. 



II. A young filament (four-celled scage), viewed from above. 



Figures 6, 8, 9, and 11 are enlarged 415 diameters; 7 and 10, 670 diameters. 



