MARINE ALG OF BEAUFORT, N. C. 441 
KEY TO SPECIES. 
Internal filaments 10 to 15 mic. wide, external filaments often long, plurilocular sporangia 
ovoid or ovoid-globose, 18 to 35 mic. wide.....).....0... eee ee eee eee 1. S. solitarium (p. 441). 
Internal filaments 5 to 8 mic. wide, external filaments short, plurilocular sporangia lanceolate, 
Obiisey torr sMiG, Wider Ns... Mantas damien th eile cc olsle al lard syacchchelals ats 2. S. invisibile (p. 441). 
1. Streblonema solitarium (Sauvageau) De Toni. Figs. 12-15. 
Ectocarpus solitarius, Sauvageau, 1892, p. 97, pl. 3, £. 24-27. 
Streblonema solitarium, De Toni, 1895, p. 576. 
Thallus mainly endophytic, filaments intercellular, 10 to 15 mic. wide, laterally and fairly pro- 
fusely branched, occasionally anastomosing, giving off upright branches forming usually simple solitary 
hairs projecting about o.r to 1 mm. above the surface, cells 9 to 15 mic. wide, 7 to 4 diameters long; 
“plurilocular sporangia’’ terminal on short, upright filaments or lateral on the longer ones, ovoid or 
ovoid-globose, 25 to 105 by 314 to 45 mic.; “unilocular sporangia’? unknown. 
On Dictyota dichotoma on the Atlantic coast of France. 
Fairly abundant on Dictyota dichotoma from the coral reef offshore from Beaufort, N. C., August, 1914. 
The external filaments of this species are plainly evident under the microscope, and the internal 
filaments can be traced for long distances in the host. The upright branches reach the exterior through 
evident pores formed in the cell walls of the host. These pores are conspicuous on the surface of the 
Dictyota after the decay of the Streblonema filaments. At Beaufort the sporangia are usually borne on 
the ends of short filaments (fig. 14), but are sometimes lateral on long filaments (fig. 15), or borne on short 
stalks on the internal filaments (fig. 13); the internal filaments are branched fairly abundantly and 
seem to anastomose occasionally (figs. 12 and 13); the external filaments are usually simple, but 
sometimes branch. Although differing slightly from the published descriptions, there seems no doubt 
of the identity of this species. 
This species is easily distinguished from the following by its larger size, its more luxuriant growth, 
the usually solitary paraphyses and sporangia, and the shape of the sporangia. It has not previously 
been recorded for North America. 
2. Streblonema invisibile sp. nov. Figs. 16-19. 
Thallus endophytic, filaments intercellular, usually 5 to 8 mic. wide, irregularly swollen here and 
there (in intercellular spaces?), variously and sparsely branched, traversing the host in all directions, 
giving off upright branches forming sporangia and short, simple hairs above the surface; “‘ plurilocular 
sporangia’’ numerous, occurring in irregular patches, accompanied by a few hairs, lanceolate, obtuse, 
25 to 55 by 11 to 17 mic., usually 4o to 45 by 14 to 17 mic.; ‘‘unilocular sporangia’ unknown. 
Thallo endophytico, filis intercellularibus, plerumque 5-8 mic. latis, hic illic inaequaliter tumidis (in 
spatiis intercellularibus?) varie et rare ramosis, passim hostem percurrentibus, ramos erectos sporangia 
et pilos breves et simplices externe formantes emittentibus; sporangiis plurilocularibus numerosis cum 
pilis paucis in locis inaequalibus, lanceolatis, obtusis, 25-55 x 11-17 mic., plerumque 40-45 x 14-17 
mic.; sporangiis unilocularibus ignotis. 
Abundant throughout the greater part of one tetrosporic specimen of Meristotheca duchassaingit J. Ag. 
collected on Bogue Beach, Beaufort, N. C., August 2, 1906. 
A minute species, invisible to the naked eye, and even with the microscope scarcely visible except 
in section. Of the described species it seems to resemble most closely Streblonema investiens Thuret. 
From this it differs in having coarser, more irregular filaments with large, irregular swellings, confined 
below the surface of the host, the hairs projecting beyond the surface being very different from the 
projecting filaments of that species. Frequently a sporangium and a hair occur together as branches 
from a common filament. 
This species is easily distinguished from the preceding by its smaller size, its less luxuriant growth, 
the occurrence of paraphyses and sporangia in clusters, and the shape of the sporangia. 
The type and the slides from which the drawings were made have been deposited in the U. S. 
National Herbarium. 
An undetermined species, apparently belonging to this genus, was abundant on several pieces of 
Nitophyllum medium collected on Bogue Beach in July and August, 1907, giving a brownish color to the 
host. The horizontal filaments branched irregularly, pursuing an irregular course among the cells of 
the Nitophyllum, from these short, vertical filaments, one to few celled, not visible to the naked eye, 
emerged to the surface. No fruit was observed, the specimens apparently being immature. 
