1914] Setchell: Parasitic Florideae, I 9 



the apical pits. The young cystoearps finally emerge and at maturity 

 become almost or entirely superficial. The pericarp is nearly globular, 

 somewhat contracted above about the carpostome and at maturity is 

 not very thick. 



Janczcivskia vernicaeformis is parasitic on Laurencia ohtiisa, is 

 abimdant in the Bay of Naples in summer (cf. Falkenberg, 1901, p. 

 259), is found in the Adriatic Sea (cf. Hauck, 1885, p. 525), and has 

 been collected on the Mediterranean coast of France (cf. Solms- 

 Laubach, 1877, p. 218, Bornet, 1892, p. 301). It is said to occur in 

 summer and autumn. 



The writer has been unable to examine specimens of Janczewskia 

 verrucaeformis and has been compelled to rely entirely upon the de- 

 scriptions of Solms-Laubach and of Falkenberg. It is desirable that 

 this species be studied anew and a more extended description pub- 

 lished, especially as regards points of difference from, and resemblance 

 to, the following species. 



Janczewskia Solmsii Setchell et Guernsey sp. nov. 



PL 2, figs. 7, 8; pi. 3, figs. 17-19; pi. 5, figs. 26, 27 



Parasitic on a species of Laurencia which has commonly passed 

 under the name of L. virgata (cf. Harvey, 1853, p. 71 ; Collins, Holden, 

 and Setchell, nos. 293, 1195), but which is probably not that species 

 but the Chondriopsis suhopposita J. Ag. (1892, p. 149), wholly or in 

 part, as was determined by a study of the type specimens. The host, 

 then, being a true Laurencia, must receive the name. 



Laurencia subopposita (T. Ag.) comb. nov. 



Chondriopsis subopposita J. G. Agardh, Anal. Alg., p. 149, 1892. 



Well-developed plants of this Janczewskia are 5-8 mm. in longest 

 diameter, globular to reniform in shape, and ivory white in color. 

 They are attached to the host for a quarter to nearly one-half its 

 circumference and the branch is strongly bent away from the point of 

 infection, as a rule over 90 degrees, the tubercle occupying a position 

 on the convex side of the curve. The surface of the sterile, antheridial. 

 and tetrasporic plants is very slightly tessellated, while that of the 

 cystocarpic plant is botryoidal in true raspberry fashion on account 

 of the projecting cystoearps. The penetration into the host plant is 

 fairly deep through scattered and slender hyplial filaments. There 



