THALLOGENS FINISHED. 



27 



Frond (L. frons, frondis, leaf). The terms thallus and 

 frond are usually 

 restricted to those 

 cellular parts which 

 are spreading and 

 leafy in appear- 

 ance ; they are al- 

 ways distinguish- 

 able from the true 

 leaf, however; for 

 they bear the floral 

 organs, whereas 

 the true leaf very 

 rarely bears them. „ ,„,„,,,, „ . , , „ „■ , , 



. ,•' , , Fia. 16. — 1, Badderlocks, Alana escvUnta. 2, Dictyoia 



And they are al- dichotoma. 3, Sea-thong, IJimanihalea lorea. 4, Sytijphlma 



ways without sto- "^'"^"'■ 



mcda, or breathing pores (Gr. stoma, mouth, pi. stomata). 

 Each cell of the thallus is not reproductive, however; 

 floral organs are produced only in special cells (sporangia). 

 These sporangia are either in superficial groups called Sari 

 (L. sorus, a heap), or in Conoeptaoks. The conceptacles may 

 be sunk in the frond ; or they may be in the form of tuber- 

 cles, as in Fucus (Fig. 17, a). But the spores themselves 

 are still naked. The flowers are always unisexual; they 

 may be dioecious or monoecious. 



48. Olive Seaweeds. — We are now fully entered upon 

 the domain of the Seaweeds, which are always lovers of 

 light, though various in texture and habit. Among the 

 olive-spored Seaweeds are the Peacock Laver (full-page 

 illustration. Lesson I.) of tropical seas, including our own 

 Southern coasts ; the edible Badderlocks of the Scotch coast 

 (Fig. 16, i), the name being a corruption of Balderlocks, in 

 honor of the long-haired god Balder ; the Dictyota (Fig. 

 1 6, 2), with its variable forms ; the great Sea-thong (Fig. 

 16, 3), with its small cup-shaped frond and long branch- 

 ing conceptacles. Here is the Dead-Man's-Rope (book 

 cover, front), so called because its slender fronds, rope- 

 like, tough, and sometimes fifty feet long, and tangled 

 into great submarine tracts, are the terror of swimmers. 

 It is a lineal descendant of the Old Chorda (Fig. 81, 



