Howe: Phycological studies 251 



ical Garden. The dissections and microscopic preparations, have, 

 however, been transferred from the glass slides, on which they 

 were studied and figured, to glycerine-jelly mounts on slips of mica. 

 New York Botanical Garden. 



Explanation of plates 11*15 



Plate ii. Halimeda scabra 



1. Photograph of plant, seven-ninths natural size. Specimen collected near 

 Jupiter Inlet, Florida, by A. H. Curtiss, September, 1895. 



2. Photograph of portion of fertile plant, one and one-half times natural size. 

 Type specimen, no. 2903 (Sands Key, Florida). 



3. Upper part of the same, three times natural size. 



PLATE 12. halimeda scabra 

 1. Portion of margin of segment, decalcified, in surface view, X 65. 

 2-6. Peripheral utricles, teased out and decalcified, in lateral view, X x 5°- 

 7. Filaments of central strand, showing mode of fusion, X 3&- 

 8-1 1. Sporangiophores and sporangia; 8 and II, X 38 ; 9 an d 10, X 2 4- I n 

 Fig. II, the prevailing distichous arrangement of the sporangia is illustrated and in the 

 older sporangia the position of the basal septum or plug is indicated. 



Figs. I, 3, 5, and 7-1 1 are drawn from the type specimen, no. 2905 (Sands Key, 

 Florida) and figs. 2, 4, and 6 from no. 2978 (Caesars Creek, Florida). 



Plate 13 



1. Photograph of Siphonodadus rigidus, natural size. From no. 1J97, collected 

 at Key West, Florida, October 30, 1902, and now preserved in fluid in the museum of 

 the New York Botanical Garden. 



2. Siphonodadus tropicus (Crouan) J. Ag. Photograph of specimen in hb. 

 Agardh, communicated by Maze as Apjohnia tropica Crouan, — ~/$ natural size. 



Plate 14. Siphonodadus rigidus 



1. Portion of plant, showing the more usual ramification, X 5- Near a, contigu- 

 ous branches connected by small fibular cells had been pulled apart. 



2. Portion of plant with numerous lateral branches or proliferations, X 5- 



3. Surface view of a somewhat similar fragment, X 5- 



4. Portion showing the small fibular cells and concrescence of branches at points 

 of contact, X J 6, optical section. 



5. 6. Fibular cells, X 66. 



7. Diaphragm showing mammilliform or tuberculiform elevations, in optical sec- 

 tion, X40. 



8. About one-fifth the area of a diaphragm, showing mammilliform or tuberculi- 

 form elevations in surface view, X 66. 



9. Cysts resulting from the division of the protoplast of a single cell, X *6. 



10. One of the filament-apices shown in Fig. 1 as it appeared after crushing under 

 the cover-slip, X J 6- 



