MARINE ALGJE OF BEAUFORT, N. C. 437 



and possibly small gametes(P). Occasionally gametes, either male or female, may 

 germinate without fusion. In addition to these, aplanospores may be formed in the 

 "plurilocular sporangia." Both "unilocular" and " plurilocular " sporangia are formed 

 in special branches or in portions of ordinary branches. 



KEY TO GENERA. 



Basal portion of the frond a filament expanded on the surface of the substratum ; sporangia 

 formed from special branches i. Ectocarpus (p. 437). 



Basal portion of the frond a filament penetrating within other algae 2. Streblonema (p. 440). 



Frond consisting of horizontal, more or less crowded, filaments, forming irregular or some- 

 what disklike patches on the surface of the host 3. Phaeostroma (p. 442). 



Genus i. Ectocarpus Lyngbye. 



Ectocarpus. Lyngbye, 1819. p. 130. 



Thallus consisting of few or many simple or branched upright filaments arising from 

 a horizontal filament; attached to substratum by the horizontal filament, often assisted 

 by rhizoidlike processes from the bases of the upright filaments; longitudinal growth in 

 the upright filaments intercalary, in the horizontal filaments apical; filaments usually 

 monosiphonous, very rarely polysiphonous by longitudinal walls here and there; asexual 

 propagation by laterally biciliate zoospores and nonmotile aplanospores produced in 

 "unilocular sporangia;" sexual reproduction by laterally biciliate motile gametes, 

 similar or differing in size, etc., produced in "plurilocular sporangia;" both organs of 

 fructification occurring in the place of branches, always singly, usually on different 

 individuals, sometimes apparently on the same individual; "unilocular sporangia" 

 usually globose, ellipsoid, or short pyriform, sessile or shortly pedicillate, opening by an 

 apical pore; "plurilocular sporangia" various in form, usually ovoid or silique form, or 

 narrowly subuliform, sessile, or pedicillate, usually opening by an apical pore, sometimes 

 tapering at the apex to a segmented hair. 



Numerous species described, but many on insufficient characters, about 40 to 70 

 recognized; in all seas, especially the North Atlantic. 



An extremely difficult genus which has not yet received sufficient study to establish 

 order among the innumerable forms occurring in it. One not familiar with the genus can 

 scarcely hope to determine the species. Fruiting specimens are always necessary. The 

 fruits are microscopic. 



KEY TO SPECIES. 



a. Frond 2 to 5 cm. tall, rarely more; "plurilocular sporangia" clavate, broad, obtuse or 



truncated at the apex, sessile i. E. duchassaingianus, (p. 437). 



aa. Frond usually 5 to 30 cm . and more tall b. 



b. "Plurilocular sporangia" conical -subulate, rarely short ovate, often tapering to a hair 



2 . E. siliculosus (p. 438). 



bb. "Plurilocular sporangia" short subulate or fusoid, not tapering to a hair 



3. E. confervoides (p. 439). 



bbb. " Plurilocular sporangia" elliptical oblong, obtuse 4. E. mitchella (p. 439). 



i. Ectocarpus duchassaingianus Grunow. Fig. 7. 



Ectocarftus duchassaingianus, Grunow, 1867, p. 45, pi. 4, f. I. 

 Ectacarfnts duchassaingianus, De Toni, 1895, p. 545. 

 P. B.-A. Nos. 985, 2077- 



