1920] Setcheil-Gardner: Chlorophyceae 271 



10. Ulva stenophylla S. and G. 



Plate 21, fig. 2, and plate 24 



Frond simple, linear-lanceolate, tapering abruptly at the base to 

 a very short, flattened, euneate stipe, 5-8 dm. high, 5-10 cm. wide, 

 plane in the middle with undulate margins ; membrane 60-1 lO^u thick ; 

 cells squarish in surface view, 14-20/t diam., 1.5-2 times as long as 

 the diameter in section, chromatophore a thin parietal layer, covering 

 a part or the whole of the cells; pyrenoids absent. 



Growing on rocks in the lower littoral belt. Central California. 



Setchell and Gardner, Phyc. Cont. I, 1920, p. 282, pi. 26, fig. 2, and 

 plate 29. 



The plants described under this name are quite distinct from the 

 other species of Ulva in shape, texture and anatomical details. They 

 are dark green, tough and harsh to the touch. The usually simple, 

 long, lanceolate shape serves to distinguish them from other species 

 at a glance. 



11. Ulva vexata S. and G. 



Plate 17, figs. 4-7 



Frond small, unbranched, rigid, linear to oblanceolate or spatulate, 

 plane or slightly undulate, more or less bullate with euneate base and 

 small, solid stipe, 1-3 cm. long, 3-10 mm. wide, dark green, black on 

 drying ; meinbrane 45-55/t, up to 100/x thick, cells vertically elongated, 

 ll-15ja, up to 18/x long, 3.5-5ja wide, with thick walls and very blunt 

 angles in surface view; chromatophore filling the cell, pyrenoids 

 absent. 



Growing on rocks along high-tide level. In the vicinity of San 

 Francisco, California. 



Setchell and Gardner, Phyc. Cont. I, 1920, p. 282, pi. 22, figs. 4-7. 

 Ulva calif ornica Reed, Two Ascomycetous Fungi, etc., 1902, p. 149 

 (not of Wille). 



Ulva vexata has been observed only in the vicinity of San Fran- 

 cisco, as mentioned above, where it grows in considerable profusion. 

 It seems quite probable that it may be much more widely distributed 

 both north and south of San Francisco. It might be suspected of 

 being a malformation due to the parasite always found more or less 

 infesting it, but the size and proportions of the cells of the less para- 

 sitized portions seem to mark it as a distinct species. 



