and on the Sexes of Mosses. 475 
Bovista 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 
so 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 Phanogamous 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 cotyledon, 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 (gemme), 
analogous to the sporulz of the Oryptogamia, are produced in the axille of 
the leaves, which, when they fall off, strike root at any part indiscriminately, 
3Q2 
