OR, PLAIN TEACHING. 



345 



The peacock's tail pavonia, 4, 

 is a curious species, growing 

 chiefly in rocky pools, where the 

 water is still, and exposed at low 

 tide. The frond is membraneous 

 and spreading, presenting various 



4 



1152. 



shades of brown, and yellowish 

 or reddish olive, which, with the 

 numerous darker and concen- 

 trical lines, and a white bloom- 

 lik3 powder, spreading over and 

 more or less modifying the multi- 

 plied hues, renders this one of 

 the most beautiful and remark- 

 able of all our marine vegetables. 

 Several generally rise from the 

 same base in erect or slightly 

 spreading tufts, seldom more 

 than two or three inches high, 

 the divisions arising apparently 

 not from growth, but from lace- 

 ration, or separation after growth, 

 the same concentrical lines being 

 continued in the same curve 

 through all the segments. 



There are few kinds of sea weed that prefer 

 any particular spot, or show a predilection of 

 one substance over another whereon to fix. 

 Deriving no nutriment from the roots, or points 

 of attachment, they need nothing further than 

 a temporary support. Thus they cling indis- 

 criminately to any solid marine body, equally 

 to granitic and calcareous rocks, to floating or 

 sunken pieces of wood, to the bones of terres- 

 trial or marine animals, to shells or polypi. 



Notwithstanding that very highly respectable 

 naturalists have averred that the growth of 

 these pla Us proceeds with the most vigour on 

 such and such substances, on some or other 

 peculiar rock in the vicinity of rivers, or in the 

 open sea, it has been fully ascertained, says 

 Dr. Hooker, by a great number of observations, 

 that marine weeds do grow with equal vigour, 

 though planted upon rocks or substances of 

 very different natures ; and that, if we ex- 

 cept some few species, those which vegetate 

 in situations where fresh water mingles with 

 salt, are generally bleached, produce little or 

 no fructification, have a thin and weak texture, 

 and contain but little soda. The qualities re- 

 quisite for their different uses are found united 

 only in such sea weeds as grow in pure salt 

 water, where they have found a spot which is 

 sufficiently tenacious to fix them in that geo- 

 graphical zone of habitation which they prefer. 

 Some kinds certainly prefer sand and mud; 

 but then their roots become elongated, and 

 strike deep, till they meet with some stone, or 

 shell, or other body, which may serve then as a 

 point of attachment, and offer the requisite 

 degree of resistance.* 



The articulated chylocladia, 5, 

 may be found either growing 

 upon rocks, or attached to some 

 larger plants. Its fronds are 

 tubular, looking like a series of 

 the cells of 5 

 an orange, 

 united at 

 their extre- 

 mities ; the ^ 

 branches 

 spring from 

 some of these 

 construc- 

 tions, and 

 the plant 

 grows in 

 tufts, from a 

 creeping fibrous base, and rises 

 in height from one to six 

 inches ; they are of a tender, 

 subgelatinous substance, and pur- 

 plish or pinky red coloured. This 

 plant, and other varieties that 

 are allied to it, are only of annual 

 duration; but the minute disc, 

 in all of them, is accompanied 

 by fibres, which creep along the 



* Rhind'a History of the Vegetable Kingdom 



1153. 



