PARASITIC FLORIDE.E OF THE CALIFORNIAN COAST. 83 



the latter at the point of attack. From this basal tissue rise small 

 leaflets, resembling the Nitophylhim in structure, which are almost 

 wholly given over to reproductive purposes. 



The structure of the reproductive organs bears a close resemblance 

 to the corresponding parts of the host plant, so much so that the 

 parasite is placed with the Nitophyllete in classification. 



Hitherto, Gonimophyllum has been observed only at Deal on the 

 British coast, where it occurs on Nitophyllam laceratum, Grev. 



Janczewskia verrucseformis Solms-Laubach, was collected at 

 Pacific Grove and Monterey Bay, California, in December, 1896, 

 and May, 1897, growing upon Laurencia pinnatifida Larax, and 

 also upon Rhahdonia Coulteri Harvey. The identification of the 

 latter specimen, however, rests upon vegetative characters only. 

 Its occurrence upon the latter form is an interesting circumstance, 

 in view of the fact tliat the various parasitic Florideje occur, in so 

 many cases, upon genera nearly related to themselves. A consid- 

 erable quantity of the Janczewskia was obtained in all stages of 

 development and including the three forms, male, female, and 

 tetrasporic. The procarps and cystocarps were carefully examined 

 and compared witli the figures and descriptions given by Solms- 

 Laubach (Mem. d. 1. Soc. nation, des Sc. natur. de Cherbourg, 

 Tome xxi, 1877) with which they closely agreed in external appear- 

 ance and internal structure. Material was also sent to Professor 

 W. G. Farlow, of Harvard University, who kindly examined 

 the specimens and verified the determination. Tlie fronds of 

 Janczeioskia grow upon any part of the Laurencia, forming small, 

 knobby outgrowths, light red in color, which are readily distinguished 

 from the darker hue of the host, so that the parasite is plainly seen 

 in the water. The plant reaches a height in some cases of five 

 millimeters. The three forms are distinct from each other and 

 when well developed have each a characteristic appearance. 



The procarps first appear as small cellular outgrowths upon the 

 surface of the frond, but the cystocarp later becomes surrounded by 

 a thick-walled pericarp, formed by the growing out of the vegetative 

 tissue about the })rocarp. The antheridia are borne in little hollows 

 in the thallus as modified lateral branches of the thallus cells. 

 The tetraspores are formed by the growth and division of cells 

 lying in the cortex of the parasite. 



