112 SPOKES ANALOGOUS TO POLLEN. [BOOK i. 



of an anther, that in Jungermannia multifida its tissue is 

 fibrous. The remarkable manner of the development of 

 sporules and pollen is a most convincing analogy; they are 

 secretions in the cellules which occupy the interior of the 

 theca or anther, and are the only instances on record within 

 my knowledge, of organised secretions in the cavities of 

 simple cellules. Although the tetrahedral union of both 

 sporules and pollen is almost always dissolved at an early 

 period, yet, in some instances, as in QEdipodium and Erica 

 Tetralix, it remains at maturity. Again, neither sporules nor 

 pollen ever have the slightest apparent organic connexion 

 with the parent plant, a most remarkable coincidence. 

 Then, to apply a chemical test, if sulphuric acid be applied 

 to the sporules, the same phenomena occur as when it is 

 applied to pollen. The effects of this test vary according to 

 the nature of the contents of the sporule, and the manner of 

 its application, which must be carefully regulated to insure 

 a satisfactory result." The sporules of Jungermannia com- 

 planata, one of the Scale-mosses, " in their natural state, are of 

 a rich olive-brown colour, and are completely filled with 

 minutely granular matter. On the addition of a small por- 

 tion of acid a few of them immediately burst, and the con- 

 tents are scattered, but the majority acquire a border of a 

 deep red colour, the contents appearing to be collected more 

 towards the centre of the cavity, and they become more 

 irregular in shape, with a projection on one side. Upon the 

 addition of a little more acid the outer coat is slowly ruptured, 

 and the contents are gradually squeezed out, the passage 

 appearing to be a work of great labour, giving an observer 

 the idea of parturition in animals. When the contents are 

 nearly out the action is more rapid, and they are ejected with 

 force, the sporule recoiling and contracting the fissure with a 

 spring, unless, as is sometimes the case, the sporule is so 

 much lacerated as to lose its elasticity." 



Lastly, "the sporules of Mosses and of some other tribes 

 commence their germination by the emission of the internal 

 lining membrane in the form of a tube, which is exactly 

 analogous to the pollen-tube. In the Mosses these tubes 

 increase by the addition of a series of fresh tubes at their 



