1919] Setchell-Gardner : Myxophyceae 95 



3. Plants solitary' or few together, epiphytic or endophytic 6 



4. Filaments in caespitose or dense layers 5 



4. Filaments in hirsutely spongy layers 5. C. pulvinata (p 97) 



5. Layer loosely caespitose, filaments 30-40/a thick 2. C. robusta fp 96) 



5. Layer loosely caesi)itosc, filaments 10-18/a thick 3. C. scopulorum (p 96) 



5. Layer dense, smooth, almost crustlike, filaments, 9-15/a thick 



4. C. Contarenii (p 97) 



6. Filaments endophytic, bulbous at the base 6. C. parasitica (p 98) 



6. Filaments epiphytic, not bulbous at the base 7. C. epiphytica (p 99) 



7. Filaments simple or nearly so, growing in tufts on other marine plants 8 



7. Filaments slightly to profusely branched, growing in layers on rocks 9 



8. 1-2 mm. high, filaments 12-20/* (rarely 40/i.) thick, ending in a long hair 



8. C. Crustacea (p 99) 



8. Not over 0.5 mm. high, filaments 24-28/a thick, ending in a short hair 



9. C. rectangularis (p 100) 



9. P'ilaments rarely and irregularly branched 8. C. Crustacea (p 99) 



9. Filaments at least frequentl}^ branched in some definite order 10 



10. Filaments attached at the base 11 



10. Filaments attached at the middle, erect at both ends. ...12. C. pilosa (p 102) 



11. Branches solitary, emerging from beneath a heterocyst 



10. C. prolifera (p 101) 



11. Branches geminate (in 2s) emerging from the interval between 2 heterocysts 



11. C. vivipara (p 101) 



1. Calothrix consociata (Kuetz.) B. and F. 



Filaments gregarions and stellately fasciculate, growing on other 

 filamentous algae, dark green, rigid, 0.5 mm. high, 21-29|Li diam., 

 decumbent, curved, and slightly tliiekened at the base; sheaths close, 

 membranaceous, dilated funnel-shaped, lamellate, inner layer brown, 

 outer layer hyaline; trichomes 12ju, diam., olive green; cells three times 

 shorter than the diameter, heterocyst basal. 



Growing on plants in a salt marsh. Whidbey Island, Washington. 



Bornet and Flahault, Rev. I, 1886, p. 351 ; Setchell and Gardner, 

 Alg. N.W. Amer., 1903, p. 197. Schizosiphon consociatus Kuetzing, 

 Phyc. Gen., 1843, p. 234, Tab. Pliyc. II, 1850-1852, p. 17, pi. 54, fig. 3. 



Calothrix consociata was included by us in the Algae of Nortli- 

 western America on tlie evidence of a single collection which has, 

 unfortunateh% not been preserved or, at least, not placed in its proper 

 place in the collections. It is, therefore, included in this account 

 without further comment. The species is closely related to C. con- 

 fervicola (Roth) Ag., from which it differs in color of trichome, 

 greater diameter of filament, and thicker sheath, whose inner layers 

 are colored. C. canfervicola, although seemingly a widespread species, 

 has not, as yet, been detected with certainty on our coast, although it 

 is to be looked for. 



