ioo TUFTS COLLEGE STUDIES, VOL. II, No. 3 



V. F.; P. B.-A., No. 1221. Cell 17-25X5 /*, lanceolate in 

 outline, more or less oblique, subacute or apiculate, apiculum 

 straight or curved ; stipe short, base not expanded. Fig. 6. 

 Mass., Cal. Europe. 



3. C. ELLIPSOIDEA G. S.West, 1905, p. 288, PI. CCCCLXIV, 

 fig. 8. Cells 15-22X8-10 //., ellipsoid, apex obtusely rounded, 

 stipe stout, very short, without basal disk ; chromatophores 4. 

 Barbados. 



The stipe is so short that the cell might be considered practi- 

 cally sessile. 



4. C. SUBULATA (A. Br.) Borzi, 1894, p. 152 ; P. B.-A., 

 No. 1370 ; Characium subulatum A. Braun, 1855, p. 47, PI. 

 V. G. Cell 12-20X4-5 M> obliquely lanceolate, sessile, with no 

 distinct stipe, but with sharply contracted base and basal disk ; 

 apex acuminate, more or less oblique; cells often gregarious, 

 with confluent basal disks. Cal. Europe. 



Class II. CHLOROPHYCEAE. 



Alga* of true green color, usually producing starch, almost 

 always with pyrenoid ; reproduction in most cases by pyriform 

 zoospores, with cilia of equal length, attached to the smaller 

 end; mostly two, sometimes four, in a few genera many cilia; 

 zoogametes of similar form, with tw r o or four cilia. 



Motionless spores of various kinds, and sexual reproduction 

 by oogonia and antheridia, are found in many genera. 



KEY TO THE ORDERS OF CHLOROPHYCEAE. 



i. Frond of one or more cells. 2. 



I. Frond usually of relatively large size, multinucleate, without dis- 

 tinction of cells. 6. SIPHONALES. 

 2. Vegetative cells ciliate and motile, always or except during resting 

 periods, or easily passing into a motile condition. 



2. VOLYOCAI.ES. 



2. Vegetative cells motionless; reproductive cells motile or not. 3. 

 3. Reproduction by zygospores formed by the union of two non-motile 



cells. i. CONJUGATES. 



3. Reproduction by zoospores, zoogametes or aplanospores, not by 



zygospores as above. 4. 



4. Cells solitary or in spherical or net-like combinations. 



3. PROTOCOCCALES. 

 4. Cells forming simple or branched filaments or membranes, rarely 



proliferously branching and vesicular cells. 5. 



5. Cells uninucleate, chromatophore usually single, disk-, net-, or 

 star-shaped. 4. ULOTRICHALES. 



