THE GREEN ALGAE OF NORTH AMERICA 381 



secondary branches, whose swollen tips constitute the surface of 

 the frond, and which when young bear each a simple or branch- 

 ing hair ; sporangium containing a single large spore, probably 

 an aplanospore, with an operculum at the base; development 

 unknown. 



Rather insignificant appearing plants, the species much alike 

 in habit, demanding dissection and microscopic examination for 

 specific determination. Howe, 1909, gives full details of foreign 

 as well as of American species. 



KEY TO THE SFECIES OF NEOMERIS. 



i. Branches of the second order subfusiform, hardly forming a cortex. 



4. N. Cokeri. 



i. Ends of the branches of the second order forming a cortex with dis- 

 tinct facets. 2. 

 2. Sporangia laterally coherent by the calcareous coating. 



3. N. annulata. 



2. Sporangia strongly calcified but mutually free. 3. 



3. Plants 1-2 mm. thick, 15-20 times as long. i. N. diiDiefosa. 



3. Plants 1.5-2.5 mm. thick, 4-8 times as long. 2. N. mucosa. 



1. N. DUMETOSA L,amouroux, 1816, p. 243, PI. VII, fig. 8; 

 Howe, 1909, p. 77, PL I, fig. i ; PI. V, fig. 20; PI. VI, figs, i 

 and 2. Gregarious or scattered, subcylindrical, slender, 20-40 

 mm. high, 1-2 mm. thick, apex acute or acuminate ; primary 

 branches 500-700 //, long, 14-30 /j. diam., 28-40 in a whorl, whorls 

 300-400, averaging 100 p. apart, more distant near the apex ; 

 secondary branches capitate, inflated at the tip to 100-185 p. 

 diam., outwardly rounded, strongly calcified except on the 

 outer surface ; sporangia strongly calcified but mutuall) 7 free, 

 containing each an aplanospore 135-160X130-155 p.. W. I. 



Europe. 



The original species of the genus, and the one to which all 

 forms were first referred ; not found in recent years in the West 

 Indies, very likely narrowly limited in its localities, like some 

 of the other species of the genus. 



2. N. MUCOSA Howe, 1909, p. 84, PI. I, fig. 5 ; PI. V, figs. 

 1-14. Gregarious, mostly in clusters of 3-20; subcylindrical or 

 fusiform, 8-20 mm. high, 1.5-2.5 mm. thick, apex acute or 

 acuminate ; primary branches 275-400 ^ long, cylindrical or 

 clavate, mostly 40-100 ^ diam., 28-48 in a whorl, whorls 120-300, 

 averaging 120 /u, apart ; secondary branches capitate, inflated at 

 the tip to 100-220 /u, diam., strongly calcified except at the end 

 surface, which is mammiform, subconical or subrostrate, with 

 very^thin, mucilaginous wall ; sporangia strongly calcified but 



