384 University of California Puhlications in Botany ["^^ol. 6 



stead of quadriciliate zoospores of two sizes, as stated by Moore; in 

 being completely embedded within the host, making entrance without 

 the formation of a tubelike projection characteristic of C. Mooreii in 

 those instances in which it partially embeds itself; and in size, being 

 40-60ju, diam. as compared with 16-26/* in C. Mooreii. It differs from 

 Chlorochytrium Beinhardtii in size and in the shape of the chromato- 

 phore; C. Reinhardtii differs from C. Cohnii Wright in shape, size, 

 characters of chromatophore, and reproductive bodies. 



Gayella constricta Setchell et Gardner sp. nov. 

 Plate 33, figs. 5-9, and Plate 32, fig. 5 



Filamentis, atro-viridibus, nanis, fasculatis, 1-4 mm. altis, basi 

 18-20/1, apice ad 175/x diam., cylindrico-clavatis, uncinatis, frequenter 

 intervallisque constrietis, basi parce ramosis ; cellulis discoideis, 10-15/i, 

 diam., primo et infero totaliter serie singulari, superne longitudinaliter 

 in giomerulis et in duobus aut multioribus planitiebus divisis et diam- 

 etron filamentorum augescentibus ; filamentis plerumque cylindricis 

 longe ad basem attenuatis, apice crassissimis, maturis passim (giomeru- 

 lis aliquibus cellularum non dividentibus) lente constrietis; parietibus 

 cellularum hyalinis, non stratosis, transversis valde tenuibus ; chloro- 

 phora singula, cellulam totam fere occupantibus ; pyrenoide obscura. 



Filaments small, dark green, somewhat tufted, 1-4 mm. high, 

 18-20/1 diam. at the base, up to 175/i at the apex, cylindrical-clavate, 

 uncinate, constricted at frequent intervals, sparingly branched at 

 the base; cells disk-shaped, 10-15/t diam., at first in a single series 

 throughout, remaining so for some distance at the base, but dividing 

 in groups longitudinally in two or more planes above, increasing the 

 diameter of the filament and preserving its cylindrical form in general 

 though gradually becoming larger, the terminal group of cells having 

 the greatest diameter ; at frequent intervals groups of 2-6 cells remain 

 undivided vertically, giving a constricted appearance to the mature 

 plants; cell walls hyaline, homogeneous; cross-walls very thin; 

 chromatophore single, occupying nearly the entire cell; pyrenoid 

 obscure. 



Growing in depressions and crevices in rock, above high-tide level, 

 kept moist by dashing salt spray. Tomales Point, at the mouth of 

 Tomales Bay, Marin County, California. 



This plant was found growing on exposed rocks in company with 

 a species of Prasiola. It is a rather unusual coincidence that the only 

 other known species of Gayelki, viz. G. pohjrhiza, is also frequently 

 found associated with a species of Prasiola. This has led to the belief 

 that Gayella is merely a stage in the life-history of Prasiola, and in- 

 deed B0rgesen (1902, p. 482) states that he has found the transition 

 stages between Gayella polyrhiza and Prasiola crispa. Collins (1909, 



