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



22. Fronds always attached. 46. 



22. Fronds floating, except in earliest stages. 



16. C. cxpansa f. glomerata. 



23. Fronds floating, except in earliest stages. 24. 



23. Fronds always attached. 28. 



24. Ramuli in long pectinate series at ends of filaments. 26. 



24. Ramuli scattered. 25. 



25. Main filaments 100-150 /u diam. 16. C. e.rpansa. 



25. Main filaments 30-60 fj. diarn. 27. 



26. Filaments 40-100 fj. diam. ; cells 4-8 diam. long. 



21. C. gracilis v. radorum. 



26. Filaments up to 160 /j. diam. ; cells 3-5 diam. long. 



21. C. gracilis v. expansa. 



27. Ramuli straight ; color light. n. C. flavescens. " 



27. Ramuli curved ; color dark. 13. C. crispula. 



28. Frond of a spongy texture. 14. C.flexuosa f. densa. 



28. Frond not of a spongy texture. 29. 



29. Ramuli short, acute, spine-like. 7. C. polyacantha. 



29. Ramuli not spine-like. 30. 



30. Articulations long, up to 20 diam. 3. C. Rudolphiana. 



30. Articulations not over 8 diam. long. 31. 



31. Ramuli long, in pectinate series at tips of branches. 32. 



31. Ramuli not in pectinate series at tips of branches. 33. 



32. Branching patent ; main filaments flexuous. 



21. C. gracilis f . australis. 



32. Branching erect ; main filaments angular. 21. C. gracilis. 



32. Branching very erect ; fronds up to i meter long. 



21. C. gracilis f. elongata. 

 33. Fronds light or pale green ; plant of exposed rocky shores, No. 



Atlantic and Pacific. 14. C.flexuosa. 



33. Frond light yellow-green ; little known So. Atlantic species. 



10. C. lutcola. 



34. Ramuli curved. 35. 



34. Ramuli straight or nearly so. 38. 



35. Frond of a spongy texture. i. C. albida v. refracta. 



35. Frond stiff and firm. 36. 



36. Ramuli closely set throughout. 37. 



36. Ramuli dense at tips only. 17. C. scitula. 



37. Main branches 80 fj. diam. or more. 23. C. refracta. 



37. Main branches not over 50 ^ diam. 24. C. Bertolonii v. hatnosa. 



38. Branches opposite or whorled. 29. C. ntpestris. 



38. Branches not opposite or whorled. 39. 



39. Filaments not exceeding 30 M diarn. i. C. albida. 



39. Filaments over 30 /j. diam. 40. 



