i8 HAKDY EOOK 0? 



represents the wood ; this layer consists of branched fibres, 

 either horizontal or vertical, and inextricably laced together : 

 and surrounding these is a denser and darker layer, analo- 

 gous to bark in trees, and composed entirely of closely- 

 packed, yet simple fibres. Outside, and forming the outer 

 coat, is a very thin layer of small cells, loosely attached, and 

 capable of being readily separated. 



The root of both species is a conical expansion, half an 

 inch or more in diameter, by means of which they become 

 firmly attached to marine rocks or stones washed by the 

 tide. Some naturalists have doubted whether sea-weeds 

 derive nourishment through the root ; but this much is cer- 

 tain, that they are materially affected by the soil on which 

 they grow, for different rocks yield plants of the same 

 family in greater or less perfection. 



The Fucus 3£ackaii, on the contrary, presents a singular 

 deviation from this general habit ; its large globular tufts 

 invariably remain unattached, resting, apparently by their 

 own weight, on mud or gravel, or among loose stones, 

 where they flourish from year to year, and fruit abun- 

 dantly. 



Every plant has its own history; and that of the Fucus 

 serratus, which abounds on all the Atlantic coasts of Europe, 

 serves to elucidate a curious fact connected with Marine 

 Botany. This plant is a world of insect life ; and in order to 

 observe its full development, collect in winter, or early in 

 the spring, fresh specimens with orange-coloured receptacles, 

 and leave them to dry partially. There will then exude, 

 from the pores of each receptacle, drops of thick orange- 

 coloured lftfuid, which, on being moistened with salt water 

 and placed under a microscope, are found to consist of 

 innumerable antheridia, the homes of small yellow aniinal- 

 culee, which quickly begin to liberate themselves, and con- 

 sequently produce those strange motions which seem irre- 

 concilable with vegetable life. 



Exotic species, such as the Sargassum vulgare and Bacci- 



