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2UUSCI. 



henceforth elongates only upwards, previously it had elongated 

 upwards and downward : the downward direction is stopped 

 as I have mentioned, why the pistil does not go on enlarging 

 is another thing. Before this rupture, the part which is to be 

 theca : assumes an oval form more or less, pressure demon- 

 strates a tendency towards a cavity in its centre, it contains 

 grumous greenish matter. 



I will here recapitulate the changes that take place in the 

 pistilla (theca) of Funaria. The first change is enlargement, 

 and the appearance of a cavity, which a short time afterwards 

 is found to be occupied by a cellular body consisting of a few 

 cells, of which the end one is always solitary ; this becomes 

 the apex of the seta. The seta grows rapidly upwards and 

 downwards, enlarging also gradually towards its head where it 

 is greener than elsewhere, as long as the tissue of the axis al- 

 lows, the seta grows downwards, as long as the pistiles allow, 

 it grows upwards. The head of the seta for a long time main- 

 tains a close connection with the apex of the pistillar cavity, 

 occupying the place, which had previously been occupied by 

 the cell forming the tip of the base of the seta. Its growth as 

 long as this happens is equal, when it bulges or becomes un- 

 equal as it cannot do otherwise, the tube of the calvptra is 

 pushed off gradually. On looking at a young theca in which 

 this pushing off has just taken place, the opercle appears 

 marked out as mammilla of denser tissue than the rest : in the 

 body of the theca an obvious cavity exists I believe between 

 the integument, and the central tissue, it is in fact a repetition 

 of this that is shewn in the structure of the columella and 

 inner membrane. 



Very soon after, the central mass is evident, the upper i or 

 nearly so is divided obviously from the lower; the whole is se- 

 parated from the wall of the theca by green tissue. Stomata 

 now exist in plenty, occupying all that part of the theca, to 

 which the central tissue, not columelloid, and which is after- 

 wards absorbed corresponds. At this stage a theca consists of 

 an outer paries, a mamillar termination which is to become 



