PL cell. aph. 2. THALASSIOPHYT JE. 
317 
Fam. II. 2. THALASSIOPHYT^. Lamouroux. 
Algarum pars , Linnaeus and Jussieu, 
Thallus coriaceous, membranaceous, or fleshy; continuous 
or jointed; fibrous or cellular; sporidia enclosed in thecae, 
or immersed in the substance of the thallus*— Plants mostly 
marine, olive green or red, absorbing water by their sur- 
face in the immersed part, but not transmitting it to other 
parts ; emit oxygen gas by the action of light. 
A. Thallus jointed, membranaceous, titbular ; joints formed 
of a simple tube; sporidia enclosed in thecae. Ceramideae. 
Thallus olive-green, gelatinous, 
from a common axis Mesogloja. 26. 
Thallus green ; secondary branches 
simple, bristlelike, swollen at bottom .. BuLBOCHiETE. 27, 
Thallus brownish ; 
branches jointed ; thecae naked Ectocarpus. 28. 
Thallus red; knots pellucid; 
thecae naked Callithamnion. 29. 
Thallus red; knots coloured; 
thecae involucrated Ceramium. 30. 
Thallus red ; knots pellucid ; 
sporidia involucrated Griffitsia. 31. 
Thallus red, gelatinous; 
branches in whirls; thecae naked Borrichius. 32. 
Thallus green, gelatinous; 
branches in whirls ; thecae naked Batrachospemum. 38. 
B. Thallus jointed , coriaceous , or membranaceous ; main 
stem solid , or compoundly jointed ; sporidia enclosed in thecae * 
Hutchinsideae. 
Thallus olive- green ; 
branches in whirls; joints simple .... Cladostephus. 84 > 
Thallus olive-green; 
branches 2-rowed; joints compound .. Sphacelaria. 35, 
Thallus red ; 
branches scattered; joints simple; Ellisius. 36, 
Thallus red ; 
branches scattered ; joints compound . . . Hutchinsia. 37. 
Thallus red, pervaded by a 
central, jointed axis Vertebrata. 38, 
