14 Universify of California Publications in Botany [Vol. 6 



by C. P. Nott and the writer. It is the plant, as noted above, which 

 has been confused with Janczewskia verrucaeformis by the writer and 

 others, and will doubtless be found wherever the Pacific Coast form of 

 Laurencia pinnatifida is abundant. 



It may be mentioned here that Reinsch (1874-5, p. 65, pi. 58) 

 has figured and described a parasite on Laurencia pinnatifida from 

 the Straits of Magellan which he names Choreocolax macronema. It 

 is possible, but by no means certain, that this plant of Reinsch may 

 ultimatelj^ prove to be a Janczewskia and possibly even identical with 

 J. Gardneri. Were it not for the host plant being identified as the 

 same, however, the suspicion would not obtrude itself in this con- 

 nection. 



Janczewskia lappacea sp. nov. 



PI. 2, figs. 9-14; pi. 6, figs. 28-32 



Parasitic on Chondria nidifica Harv., the plants of this species 

 form pink burrlike growths on the stems or branches, or at the inter- 

 sections of the two, and reach a maximum diameter of from 3-5 mm. 

 The thalli in this species are more regTilar in general outline than 

 those of the last species, being flattened globular with radiating free 

 branches which are proportionally long, especially in the tetrasporic 

 and cystocarpic plants. 



The penetration of the host plant is most conspicuous and most 

 complete and there is usually a slight bending at the point of infection. 

 The cells of the body of the tubercle are gorged wnth granules, as are 

 also the short cells of the branched, hyphal, penetrating filaments 

 which encircle all the inner cells of the host and show, in a cross- 

 section (pi. 6, figs. 28, 29), as a perfect network, the slender, granular 

 cells of the hyphal filaments being conspicuous among the large, 

 rounded, clear cells of the host. Pit connections between the haus- 

 toria of the parasite and the cells of the host are conspicuous (pi. 6, 

 fig. 29). The epidermis of the host has the cells very much elongated 

 in the region of the attachment of the parasite. 



The tetrasporangial plant (pi. 2, figs. 10, 13) is about 5 mm. in 

 greatest diameter, flattened globular, with the tubercle rounded and 

 the numerous spreading, slender free branches 1.5-2 mm. long. 



