262 The Scottish Naturalist. 



This species grows in spreading, short, dense turfs in salt 

 marshes, amongst grass which is sometimes entirely submerged. 

 It is monoicous, the oogonia are either sessile or on short lateral 

 branches, and are obovoid or pear-shaped. The antheridia are 

 sessile, lancet-shaped, and scattered along with the oogonia near 

 the tips of the branches. Farlow believes that he has seen on this 

 species the asexual fruit, in the form of oval spores, smaller than 

 the oospores, borne at the tips of short branches given off at right 

 angles to the main filaments. The short branches fall off with the 

 spores, and the latter after some time escape from the ruptured 

 end of the cell. They are motionless, and are destitute of cilia. 



V. synandra, Woron. (Fig. 3). Greenod, near Ulverstone ; 

 Dr. O. Nordstedt, Aug., 1885. 



This species grows near high-water mark, on soft mud, in exten- 

 sive patches about 1 inch high. The oogonia occur on the same 

 threads as the antheridia, and close to the latter. The species is 

 easily recognised when in fruit by the enlarged chlorophyll cell 

 attached to the thallus by a short empty cell, and bearing a number 

 of hooked antheridia on its surface. The oogonium is also fur- 

 nished with a decurved hooked beak. The asexual spores are 

 densely ciliated. 



Vaucheria sphserospora, Nordst. Dr. Nordstedt does 

 not appear to have found the typical plant in this country, but he 

 met with the var. dioica, Rosenv., abundantly, at Maldon, in Essex ; 

 in fruit in Aug., 1885. (Fig. 6 ; var. dioica Fig. 6 a). 



The description given by Harvey of his V. velutina, Ag., applies 

 tolerably well to this plant. It forms a short, pale green, dense, 

 spreading turf, on sandy mud in creeks, where the water is some- 

 what brackish. The tufts are densely intricate, with short erect 

 lateral ramuli. It is visible about \ inch above the mud. The 

 oogonia are pear-shaped, tapering into a well-marked pedicel, the 

 oospore being globular, and nearly filling the swollen head of the 

 oogonium. The antheridia in the var. dioica are scattered on 

 distinct threads, sometimes several near together, and sometimes 

 two, or even three, on one transparent intervening cell. The 

 antheridia are irregularly lancet-shaped, acute, with one terminal, 

 and one or two lateral openings. It differs from all the other 

 marine species in containing a chlorophyll cell in the pedicel of 

 the oogonium. The oogonium generally terminates in a short 

 recurved branch, and is separated from the thallus by a colourless 



