MARINE AIGM OF BEAUFORT, N. C. 463 



cystocarp. The nonmotile spores (carpospores) borne in these fruits are discharged 

 into the water and germinate immediately. Carpogonia and sporocarps are borne 

 externally or immersed on specialized or unspecialized portions of the thallus. Sexual 

 and asexual cells are nearly always produced on different individuals, the sexual and 

 asexual plants, at least in some cases, alternating with each other in the life cycle; 

 antheridia and carpogonia are borne on the same or different individuals. Almost 

 exclusively marine, a few in fresh water, some endophytic. 



About 3,000 species throughout the world but most abundant in warm seas. 



KEY TO CLASSES. 



Thallus filamentous or foliaceous, usually unbranched; asexual and sexual organs formed 

 from ordinary vegetative cells i. BANGIOIDE^E (p. 463). 



Thallus variously formed, usually branched; asexual spores (usually four) produced in special 

 sporangia; sexual gametes borne in antheridia and carpogonia 2. FLORIDE.5J (p. 467). 



Class 1. Bangioideae De Toni. 



This class contains only one order. 



Order Bangiales. Schmitz and Hauptfleisch. 



Thallus filiform, disk shaped or foliaceous; asexual propagation by spores produced 

 from ordinary vegetative cells or by akinetes; sexual reproduction by apparently non- 

 motile spermatia and eggs produced from ordinary vegetative cells. 



Family BANGIACE^E (Zanardini) Berthold. 



Thallus small or of medium size, attached to rocks, etc., colored various shades of 

 red or purple, sometimes blue or greenish, sheets of one or two layers of cells, or of 

 disks, or of filaments composed of one or more cell rows; cells having a single nucleus 

 and a single star-shaped chroma tophore; asexual propagation by spores produced one 

 or more from ordinary vegetative cells, occasionally by akinetes; sexual reproduction 

 by minute, apparently nonmotile spermatia, which are discharged into the water, and 

 large eggs which are retained within the enveloping organ; numerous spermatia formed 

 by division of ordinary vegetative cells which function as antheridia; eggs usually pro- 

 duced singly, formed from ordinary vegetative cells, which may in some cases be regarded 

 as simple carpogonia, since they frequently form hairlike protuberances somewhat 

 similar to the trichogynes of Floridese, the spermatia then fuse with these protuberances; 

 the fertilized egg divides into a few (usually eight) spores, or, rarely, may be transformed 

 directly into a single spore; both the sexually produced and the asexual spores are 

 naked when first discharged into the water, and frequently are possessed of slight 

 amoeboid movement, but are soon surrounded by walls and apparently are always 

 passively transported. Asexual and sexual organs are, in different species, produced on 

 the same or on different individuals, as is also the case with male and female organs. 



About 45 species, nearly all marine, a few in fresh water, throughout the world, 

 especially in temperate seas. 

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