1914] Setchell: Parasitic Florideae, I 13 



tration the epidermal cells of the host elongate in the anticlinal direc- 

 tion to twice their length and become less than half their normal width, 

 thns producing a coiis])i('U()iis palisade-like layer. 



The tetrasporic plant is the largest, at least among those observed 

 by the writer, reaching 10 mm. in its greatest diameter, ordinarily, 

 however, as much as 8 mm., and is a more or less flattened cushion 

 fl^l. 1. fig. 5), covered with slender, free branches projecting as mnch 

 as, or a little more than, 2 mm. These free branches are blunt, of 

 equal diameter throughout, and simple. The antheridial y)lant is 

 usually much smaller, about 4 mm. in greatest diameter, more nearly 

 globular or somewhat flattened (pi. 1, fig. 6: pi. 3, fig. 16), more or 

 less moriform, with the crowded short free branches which are 0.6-0.8 

 mm. long and slightly enlarged above in fertile condition. The cysto- 

 earpic plant (pi. 1, fig. 4; pi. 3, fig. 15) is nearly as large as the tetra- 

 sporic, reaching a greatest diameter of 8-9 ram., is flattened and 

 irregular, with its crowded free branches 1.0-1.5 mm. long and more 

 or less swollen above at maturity of the cystocarps, of which two 

 frequently occupy the same summit. 



The tetrasporangia are tripartite and subepidermal on the outer 

 surfaces of the free branches. The antheridia occur in almost globose 

 or ellipsoidal conceptacles lining the entire inner surface. They occur 

 in closely crowded, elongated, simple plumes which project inwards 

 towards the center (pi. 5, fig. 25). They are in structure and arrange- 

 ment very similar to those of J. moriformis, but they are more slender 

 and more crowded. 



The cystocarps occur singly or in twos at the tips of the free 

 branches. The walls are moderately thick and the spores and sporif- 

 erous filaments are more slender and more eroAvded than in anv of 

 the preceding species. 



Janczeirskia Gardncri differs from J. moriformis in the uniformly 

 greater length of the free branches and in the dimensions and abund- 

 ance of the antheridial plumes and the sporogenous tissues in the 

 eystocarp. 



Janczcicskia Gardncri is found on Laurcncia pinnatifida, particu- 

 larly on that broad, coarse form called L. ^pcctohilis by Postels and 

 Ruprecht. It has been collected on Vancouver Island, B. C, by John 

 ]\racoun ; at W]iidl)ey Island, Washington, and near San Francisco, 

 Pacific Grove and San Pedro, California, by N. L. Gardner; at Fort 

 Roas (cf. Phyc. Bor. Am., no. 887) and about San Francisco. Cali- 

 fornia, by the writer; and at Monterey and Pacific Grove. Califoi'iii;i. 



