254 VEGETABLE ORGANOGRAPHY. 



and from the base of which is prolonged a radicle sur- 

 rounded with little radical fibrils ; it is not then doubt- 

 ful that the central body of this apparatus is a repro- 

 ductive body. But is it a monospermous fruit, as 

 Vaucher seems to believe ? Is it a fruit containing 

 several seeds, one only of which is developed at germi- 

 nation ? 



This remains to be investigated. 



§ 2. — Thalassiophytse. 



I designate with Lamouroux under this name all the 

 marine Algae described under the names of Fucus, Cera- 

 mium, and Ulva. In order to make their reproductive 

 system known, I shall select some examples from the 

 different groups. 



Fucus vesiculosns presents at the extremity of its ra- 

 mifications kinds of oval swellings ; these are not pro- 

 jecting tubercles, but simple dilatations of the tissue: the 

 surface of this dilated part presents kinds of round pores 

 disposed regularly. When, at the period of fructifica- 

 tion, this dilated part of the frond is cut, we see that it 

 is formed internally of a cellular tissue, very much swol- 

 len up with an abundant watery mucus differing in con- 

 sistence from the juice of the rest of the plant. Under 

 each of the pores on the surface is found a round mass, 

 which seems formed of divided filaments, transparent, 

 and interlacing one another : these masses, seen by the 

 naked eye, do not bear a bad miniature resemblance to 

 the prickly husk of the Chestnut. If they be cut across, 

 we find in their interior a grand number of oval mem- 

 branous bodies, which, at maturity, appear isolated from 

 the rest of the tissue, and destined to come out of the 



