INTEODUCTION TO CEYPTOGAMIC BOTANY. 171 



broken up into four pyramidal masses from the centre, 

 or in those cases in which an elongated or elhptic form 

 is assumed, by three parallel divisions, or by one or more 

 parallel divisions, with the addition of one in a vertical direc- 

 tion. The former were once considered as ternate granules, 

 but it is evident that in a globe so divided, if the point of 

 juncture of three divisions occupies the centre of the point of 

 view, the fourth will be wholly concealed.* 



146. A discussion was moved some years since, in a very inge- 

 nious and beautifully illustrated memoir on the Algse of the 

 Red Sea, as to the relative value of these two forms of fruit, by 

 Decaisne. He inclined to the view that the more perfect form 

 was exhibited by the tetraspores, but as this mode of growth 

 is normal in many of the lower Algae, and is in them certainly 

 inferior to the formation of spores in the conjugate Algse, or 

 even to the cysts of Vaucheria, I cannot subscribe to his 

 notion, but regard the tetrasporic form as requiring a very 

 inferior effort of nature. Indeed, it is probable that the notion 

 is correct which regards them rather as a sort of buds, a notion 

 which is supported by the fact, that the plants which bear 

 them are generally more luxuriant than those which produce 

 the other form of fruit. What it is which leads one plant 

 constantly to produce a particular form of fruit, is at present 

 a matter of which we can only profess our complete ignorance ; 

 though the fact of two kinds of fruit being produced, not only 

 in such genera as Atriplex, but in a multitude of Compositw, 

 which yet give rise to plants which cannot be distinguished 

 from each other, is so much in point, that we ought not to be 

 surprised at something similar taking place in Algse. As the 

 point is one at a satisfactory solution of which we are not at 

 present likely to arrive, we may content ourselves with our 

 knowledge of the fact, considering it meanwhile as one of 

 those wonders which abound so greatly amongst Cryptogams. 

 Both these forms are equally capable of propagating their 

 species, but it is very probable that for this end the concep- 



* In the curious Lepidostrobus, figured by Mr. Brown in the Linnsean 

 Transactions, one of the four divisions of the spores is usually suppressed. 



