282 University of California Puhlicutions in Botany [Vol. 7 



in the size of these two species, jis well as in their methods of develop- 

 ment. M. zostericola is diminutive, remains saccate for some time, and 

 splits longitudinally, forming several lobes broadening outward. M. 

 areolaium verj'^ closely resembles the genus Prasiola in the grouping 

 of the cells as seen in surface view. 



Ulva stenophylla sp. nov. 



I'late 26, figure 2, and plate 29 



Thallo siiii])lici, lineari-lanceolato, ad basim in stipitem brevissi- 

 mum, coinplanatum, euneatum longe attenuato, 5-8 dm. longo. 5-10 

 cm. lato. medio piano, marginibus undulatis ; raembrana 60-1 10/x 

 crasso, cellulis e superticie quadratis, 14— 20/<, diam. in sectione trans- 

 versali, 1.5-2-plo diam. longioribus; chromatoi)horis tenuibus, parie- 

 talibus, omnino aut i)artim cellulam tegentibus ; pyrenoidibus nuUis. 



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

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

 jdane in the middle with undulate margins; membrane 60-110/x thick; 

 cells squarish in surface view, 14-20/1, diam., 1.5-2 times as long as 

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

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



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

 Type no. 5445 (Herb. Univ. Calif., no. 98511), Setchell. 



The plants described under this name are quite distinct from the 

 other species of Ulva, in shape, in texture and in 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. 



Ulva vexata sp. nov. 



Plate 22, figures 4-7 



. Thallo parvo, simplici, rigido, lineari ad oblanceolato aut spatulato, 

 piano aut parce undulato, plus minusve bullato, basi cuneato stipite 

 parvo et solido, 1-3 cm. longo, 3-10 mm. lato, atroviridi, siccitate atro; 

 membrana 45-55/1, usque ad lOO/x crassa, cellulis verticaliter elongatis, 

 11-15/1 usque ad 18/t longis, 3.5-5/t crassis, parietibus crassis et e 

 superticie angulos obtusos ostendentibus ; chromatophoris cellulas im- 

 l)lentibus: ))yrenoi(libus nullis. 



Fi-oiid small, unbranehed, rigid, linear to ol)hinceolate or si)atulate, 

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

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

 drying; membrane 45-55/i, up to lOO/i thick, cells vertically elongated, 

 11-15/1, U]) to 18/t long, 3.5-5/x wide, with thick walls and very blunt 

 angles in surface view ; chromatophore filling the cell, pyrenoids absent. 



