252 Mr. J. W. Howell on the Structure of the Capsule 



parietal placentas, which is the normal state. This co-exist- 

 ence of structural progression and retrogradation is not pe- 

 culiar to the present case, but obtains in all kinds of organized 

 beings, and effectually negatives any attempt at linear arrange- 

 ments, either of individual organs or of species themselves.] 



In Meconopsis the additional carpels (only sketched forth 

 and indicated, as it were, by the additional stigmas in Hunne- 

 mannia and Eschcholtzid) are perfected, each carpellary valve 

 contributing by its margins to the formation of two parietal 

 linear placentas, which latter correspond with the stigmatic 

 rays. Each stigmatic ray is formed precisely similar to the 

 stigma of Macleaya, Chelidonium and Glaucium, being fur- 

 nished with a central depressed line, indicating its formation 

 from the union of the corresponding halves of the two con- 

 tiguous carpels. 



In Argemone the radiated stigma presents an undulatory 

 folded appearance in consequence of the increased growth of 

 the intervening tissue, which in the preceding genera (except- 

 ing Eschscholtzia) separates the lateral portions of the stigmatic 

 extremity of each carpel. 



[If the reader experience any difficulty in understanding the 

 complicated folded stigma of Argemone, let him compare one 

 of the folds with the stigma of Glaucium, and the difficulty im- 

 mediately vanishes ; for he will perceive that the undulated 

 stigma of Argemone results merely from the structure of Glau- 

 cium being several times repeated, and arranged in a circular 

 manner around an imaginary axis.] 



We now arrive at Papaver, in the different species of which 

 the capsule presents several states of complication by the suc- 

 cessive addition of a greater number of carpels, which in P. 

 somniferum sometimes amount to sixteen. The parietal pla- 

 centas, which in all the preceding genera are linear, now pro- 

 ject in towards the centre of the capsule, partially dividing it 

 into as many imperfect cells. The stigmatic rays, which, as 

 in the preceding instances, are equal in number to the pla- 

 centas, and opposite to them, are, as already described, double, 

 and only differ from those of Argemone in having the inter- 

 vening tissue, which separates the two margins of the stig- 

 matic extremity of each carpel, plane instead of folded. 



We now see that the radiated stigma of Papaver, however 

 much it may appear to resemble that of Nymphcea, differs from 

 it in such important particulars as effectually to prevent any 

 union of the two orders to which these genera belong ; unless, 

 indeed, species of Nymphceacece should hereafter be discovered 

 with bi-carpellary capsules, which woukl form, with Bocconia, 

 the means of union with Papaveracece at the commencement 

 of the two series. 



