1920] Setchell^Gardner : Chlorophyceae 155 



rliizoidal portion. It is now placed near to ProtosipKon, which it 

 more closely resembles than any other genus. The description given 

 above is adapted from Collins {loc. cit.) and expresses well the general 

 characters. 



Halicystis ovalis (Lyngb.) Arescli. 

 Plate 14, fig. 3 



Thallus solitary or gregarious, obovate-ovoid, 0.5-1 cm. high, 

 about half as wide ; membrane tough, 10-12ja thick ; basal prolongation 

 penetrating the substratum; zoospores 12-14/x long, 7-8/x wide; 

 gametes ( ?) 7-8/a long, 2-3/a wide. 



Growing on Lithothamnwn and on other crustaceous corallines 

 adhering by means of the rhizoidal portion penetrating deeply into 

 the host. Vancouver, British Columbia, to Monterey, California. 



Areschoug, Phyc. Scand., part II, 1850, p. 447 ; Kuckuck, Abhandl. 

 Meeresalg., 1907, p. 139, pi. Ill; Collins, Green Alg. N. A., 1909, 

 p. 372. Valonia ovalis (Lj^ngb.) Agardh, Sp., vol. 1, part 2, 1822, 

 p. 431; Saunders, Four Siphon. Alg., 1899, p. 2, pi. 350, f . 2 a, b ; 

 Setchell and Gardner, Alg. N. W. Amer., 1903, p. 232. Gastridium 

 ovale Lyngbye, Hydr. Dan., 1819, p. 72, pi. 18 B. 



This ver}^ curious and interesting species has been most carefully 

 studied, described and illustrated by Kuckuck (1907) and seems to 

 be the same as that found on our own coast. Very little material is 

 available for study, neither of the present writers has had the oppor- 

 tunity of collecting it, and only one of them (Setchell) has had the 

 privilege even of examining a living plant.. In general appearance 

 and structure, however, the Pacific Coast plant agrees thoroughly with 

 the descriptions of the European writers. 



It was first credited to our coast by Saunders (1899) who found 

 it at "Point Lobos" (or Point Carmel) in Monterey County, Califor- 

 nia. Later it was found in successive years at a locality near Point 

 Cypress, only a few miles north of "Point Lobos" by Professor Harold 

 Heath of Stanford University, and the third and last locality is Port 

 Renfrew in British Columbia, where it was collected by Misses Butler 

 and Policy. It is alwaj^s found growing on living crustaceous coral- 

 lines into the thallus of which it bores its way. It will probably be 

 found at other points along the coast, since it undoubtedly escapes 

 observation as it is small and grows at, or just below, the lowest 

 tide mark. 



