540 



MA RSILIiACK.t. 



In Azolla the evidence consists in the derivation of the 

 grains from without, on the browning of the foramen after 

 the appearance of the grains within the ovulum, and on the 

 subsequent new growths presumably excited into action 

 thereby, and their direction, which proceeded from the point 

 next the point of application of the supposed fecundating in- 

 fluence.* 



1 am not willing to omit an analogy with Phanerogamic 

 fecundation derived from the apparent inaptitude of the 

 means to the end. It has always appeared to me remarkable 

 by what means a tube of such tenuity, of such flexibility, and 

 with such an obtuse point as a pollen tube can not only get 

 at the nucleus, but overcome the resistance presented by its 

 solid tissue so far as to penetrate it to a certain, and often 



* Assuming fecundation to take place in Azolla and salvinia, there will 

 be, I think, three modifications at least of this phenomenons among the 

 higher acotyledonous plants. In one the male influence is applied to the 

 apex of the pistillum, in the second to the nucleus without the interven- 

 tion of a pistillary appartus. In the third the male influence is exerted 

 on the frond itself, and is followed by the development of the young 

 capsule from a point in the substance of the frond corresponding. to and 

 sometimes distant from the place to which the male influence has been 

 applied. 



This is founded on observations made on Anthoceros in 1836, from 

 which it would appear that the place of exsertion of the future capsules 

 is pointed out by a slight protuberance, over the apex of which a flaker 

 of matter like the male matter of Musci and Salvinia is spread, sending 

 down to some distance within the frond and tube-like process which 

 causes the dislocation of the cells of the tissue with which it comes into 

 contact. • 



The future capsule is stated in my notes not to be appreciably pre-ex- 

 istent, and its situation, which it exactly under the line of direction of 

 the descending process, above mentioned, is only pointed out by a bulbi- 

 form condensation of the tissue of the frond. The young capsule during 

 its development ascends along the same line, and pushes before it a cor- 

 responding cylindrical body of the tissue of the frond, the calyptra of 

 authors. 



I have never since had an opportunity of verifying these observations 

 which, if correct, may I think prove of some importance. 



