On Azolla and Salvinia. 245 



So much so, that each joint of the moniliform filaments, or 

 each grain as found in the ovulum, is not distinguishable 

 from the simplest forms of pollen grains, which I take to be 

 those in which no outer integument is developed, as in Naias, 

 Zanichellia, etc. and which are consequently simple mem- 

 branous bags or sacs. The chief* discrepancy is that the 

 grains of Azolla do not undergo any elongation in the per- 

 formance of their supposed functions as appears to be uni- 

 versally the case in phaenogamous plants, even in those in 

 which the pollen grain is bodily received into the nucleus :f 

 and contrariwise no growth, beyond mere extension, has been 

 observed in phaenogamous pollen exterior to the ovulum. J 



It is scarcely, however, to be expected that analogies, pro- 

 ducable through every stage of any particular process in 



which they belong, their structure is different, and they generally dehisce. These 

 are all strong objections, particularly when it is considered that if these anthers be 

 pollen grains they represent the inner membrane of ordinary pollen. 



But the difference is not unadjustable in my opinion, if the anther of Mosses is 

 compared with the very young phaenogamous anther, at that period when the grume, 

 from which the mass in which the parent cells are developed originates, is so 

 fluid that pressure causes an escape of minute fovillar matter not unlike the con- 

 tents of the anthers of Musci. 



* I do not mention their organic connection with the plant, because that may be 

 the consequence of their not being provided with a proper protecting organ. It is 

 besides at the most only very partial, and it is not greater than that occurring in 

 many forms of supposed anthers among these kinds of plants ; i. e. where the anther 

 consists of a cell terminating a stalk of a single row of cellules, to which type the male 

 organs of Azolla and Chara are easily reducible. For any difficulty that might be 

 objected to the attributing fecundating powers to each component cell (not ex- 

 clusively to the terminal one) becomes lessened by the remarkable form of the male 

 organs of Drepanophyllum and certain Neckerae and Syrhopodon. 



f e. g. Cycas. 



X A remarkable circumstance was observed once or twice in some of the joints 

 of the moniliform filaments, while attached to the axis. Some of them were a 

 good deal enlarged, of a yellow green tint, with a nucleus towards either end, 

 or with only one near the base when the enlarged joint happened to be the ter- 

 minal one. Others near the terminal ones had become divided into two by a line 

 across the middle, the two cells thus resulting being broader and more bef dlike 

 than before. In some others again close to either end was a small nucellus, which 

 corresponded with the contiguous nucelli of the neighbouring joints : and near 

 each nucleus was observed the shadowing out of a large cell. 



