140 THE VEGETABLE KINGDOM. 



for a long time and is commonly still used, indicates that the 

 reproductive organs are invisible, hence the expression 

 used by one of Shakespeare's characters, "We have the 

 secret of fern seed, we walk invisible ;" but this is not really 

 the case, for the "sorri" at the back of fern-leaves, are 

 vessels filled with spore-cases each having a number of 

 angular seeds within it ; the lower tribes of the acrogens 

 do not commonly grow from seed but by an extension of 

 their several parts by the development of the cells of which 

 they are composed, and by their separation into portions. 



Pew of this tribe have anything like true woody 

 texture, except their highest order, the ferns, which form 

 some of the most beautiful objects in the vegetable 

 world. Few of the family of acrogens are of much 

 direct use to man, the mushroom tribes are very generally 

 eaten where they abound, the lichens of the arctic regions 

 form the food of the reindeer (the greatest friend of man 

 in these cold climes) as well as, in part, the food of man 

 himself; but although these lowly plants serve man but 

 little, directly, there is not a shadow of doubt that they 

 have as important an office to fulfil as any other family or 

 tribe of organised creatures, whose purpose may meet the 

 eye more plainly. Eor all the members of creation form, 

 as it were, the links of one great chain, and were but one 

 removed, though it might perchance be only some poor weed 

 or lowly moss, yet might it cause the whole to be annihilated; 

 for certain earthy matters enter into the structure of all 

 plants, and it appears to be the wonderful office of some of 

 these lowest tribes of plants to prepare this earthy matter 

 for its reception into the systems of higher organisms, for as 

 silica is one of the primitive rocks of the earth and is only 

 found in fragments, from the largest to the sand on the sea- 

 shore, which is nothing but a collection of minute fragments 

 of quartz worn small by attrition, yet a grain of sand is a 

 gigantic mass of rock in comparison with the thin porous 

 hollow shells of the Diatomacese, &c., and by far too large 

 to be absorbed or dissolved so as to be taken into the 

 systems of other plants that may require it, which plants 

 would cease to exist if this earth were not thus prepared 



