73 



161. Threads of the fruit much branched, many of them sterile. 

 Upper branches of the fruit-bearing threads ripening earlier than 

 the lower Fruit more or less lobed, each lobe producing numer- 

 ous spores grouped in no special order in mucus. Tetraspores 

 scattered through the frond or produced in special branches. 

 Frond sometimes tubular, but more commonly of a compacted 

 mass of cells, the outermost cells sometimes joined to form vertical 

 threads. RHODYMENIACE.E. 



Fruit-bearing threads ripening at about the same time. Spores 

 single, borne in the terminal joints of the threads. 



i 



Spore-bearing threads in very dense, numerous, short bundles. Tet- 

 raspores produced among the cortical threads of the frond, divided 

 crosswise. Frond made up of cells or threads very densely 

 interwoven. Fruit single or joined by twos. GELIDIACE.E. 



Spore-bearing threads long and branching, radiating in bundles 

 from the placenta, producing single spores in the larger, terminal 

 club-shaped cells. Tetraspores in the cortical stratum of the 

 frond, or in warts made up mostly of threads. Frond tubular or 

 solid, composed of threads or of cells not arranged in straight 

 lines. CHONDRIE^E. 



162i Fertile fruit threads bearing many spores in their upper joints. 

 Fruit compound, the parts arranged radially around the placenta. 

 Spores contained in mucus. Tetraspores divided by zones. 



ARESCHOUGIEJE. 

 Spores single, in the upper joints of the fertile spore threads. 



Fruit compound, the parts radially disposed around the central pla- 

 centa. Spores pear-shaped or club-form, borne singly in the ter- 

 minal joints of the thread branches, not contained in mucus. 



SOLIERIACETE. 



Fruit simple, with hardly any proper placenta, but made up of a 

 bundle of spore-bearing threads. Spores borne in the upper 

 joints of the threads. Frond often cylindrical, gelatinous, some- 

 times covered with a crust of carbonate of lime. 



HELMINTHOCLADE^. 



