and on the Sexes of Mosses. 47% 



Bovlsta giganteum have been computed by Dr. Lindley, in his valuable 

 Introduction to Botany, page 7, to increase at the rate of sixty-six millions in 

 a minute. I cannot conceive any mode by which this astonishing rapidity of 

 development can possibly occur, but by the rapid secretion of fluid material, 

 which instantaneously separates at innumerable distinct points into its solid 

 and aqueous constituents. 



We have now, I flatter myself, obtained knowledge of the structure of the 

 organs of reproduction sufficient to enter on the subject of the sexes. As the 

 theory of Hedwig is the only one that has obtained any consideration, I shall 

 confine my observations to that. In the Linnean Transactions, vol. x. p. 312, 

 Mr. Brown says, " The account which the celebrated Hedwig has given of 

 the sexes of Mosses seems to be founded on so ample an induction, and is now 

 80 generally received, that it must be unnecessary to notice the arguments 

 which mere theoretical botanists have, from time to time, produced against it." 

 Dr. Hooker observes on this subject, in a note to the second part of the Flora 

 Scotica, " The more intimately we become acquainted with the reproductive 

 organs of the Acotyledonous or Cryptogamic plants, the more apparent is it, in 

 my opinion, that there are no sexes, as in the Phccnogarnous plants, no sta- 

 mens and no pistillum, nor anything analogous to them ; consequently no true 

 seed, which can only be produced through their cooperation. The structure 

 of the seeds themselves (more properly sporules) tends greatly to confirm such 

 an opinion, there being, in reality, no distinction into cotyledmi, radicule or 

 plumule, in short, no embryo, any more than there is in the little bulbs seen 

 upon the stalks of the Onion tribe, and upon the Polygonum viviparum, &c., 

 which yet equally produce perfect plants. A sporule has alike the power of 

 producing from every part of it, either stem or root, as circumstances may 

 require: but it is quite otherwise with the true seed." Dr. Greville and 

 Mr. Arnott in their Memoir remark, that " It is extremely improbable that 

 Acotyledonous plants are furnished with stamens and pistils, and that through 

 their agency the seeds or reproductive sporules are formed. This idea is cor- 

 roborated by the common phenomenon which takes place in those Cotyledo- 

 nous plants which rarely bring their seeds to maturity ; small bulbs (gemmce), 

 analogous to the sporulae of the Cryptogamia, are produced in the axillae of 

 the leaves, which, when they fall off", strike root at any part indiscriminately, 



3 Q 2 



