I08 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN 



by southern New England plants that have been taken to be 

 identical with it are very different in form and size from those of 

 this Beaufort plant. Sterile specimens of D. vaucheriaejormis 

 collected by Harvey at Key West differ from D. turbinata in their 

 yellowish green color, less nitent facies, manifestly erect and 

 densely tufted habit, consistently dichotomous branching, and 

 smaller more polygonal chloroplasts. 



Streblonema solitarium (Sauv.) De-Toni, Syll. Alg. 3: 576. 



1895- 

 Ectocarpus solitarius Sauv. Jour, de Bot. 6: 97, 126. pi. 3. f. 24-2J. 



1892. 



On Dictyota dichotoma, dredged "in iT^yi-i^. fathoms," Lewis 

 Radcliffe, August 11, 1914; accompanied by Elachistea stellulata, 

 Phaeostroma pusiUum, Acrochaetium affine, etc. This species was 

 originally described as an endo-epiphyte of Dictyota dichotoma, 

 Dictyopteris [Neurocarpus] polypodioides, and Taonia Atomaria 

 from near Le Croisic on the western coast of France. In the 

 Dictyota, in France, it is commonly associated with Elachistea 

 stellulata, as is also the case in North Carolina. Both the Streblo- 

 nema and the Elachistea have inconspicuous endophytic vegetative 

 filaments that make their way extensively in or near the cell 

 walls of their host. The cortex of the host (in this formalin- 

 preserved material from North Carolina) is so transparent that 

 by focusing into and through it with the compound microscope 

 one may follow the course of the interior filaments in a tolerably 

 satisfactory manner. These filaments, in the case of the Streblo- 

 nema, are found chiefly in the plane of juncture of cortex and 

 medulla, but they often penetrate the medulla and sometimes 

 reach the opposite cortex. They commonly follow the vertical 

 and longitudinal walls so closely that they are not readily obvious 

 on a casual examination. The filaments may seem to anastomose 

 occasionally, but this is perhaps an oi)tical illusion due to the 

 close crossing of filaments in slightly different planes. The 

 exterior part of the plant in its simplest conditions consists simply 

 of a single sessile plurilocular sporangium, or the sporangium 

 may be terminal on a simple few-celled exterior filament, or, in 

 better-developed conditions, the exterior filament, remaining 

 simple or subsimple, may attain a length of 750 ^ and may bear 



