378 MORPHOLOGY. 



mart long since mentioned, that in several plants the stigma is clothed by 

 a structureless pellicle (cuticula), as, for instance, in Nuphar, Nyctago, 

 and Hibiscus. Here he erred on account of examining the stigmas too 

 late, after the secreted viscid matter had become solidified : at the time 

 when the flower opens this imaginary pellicle is a thickish and amor- 

 phous fluid. In most plants, however, Brongniart had recognised the 

 real nature of it, although he had not observed its gradual formation as a 

 secretion from the neighbouring cells. Quite recently, Hartig has, from 

 the most imperfect observation of this substance, built up a comprehen- 

 sive so-called theory, including not merely impregnation, but even cell- 

 formation, which, in reality, contains nothing but imperfect observations, 

 and these inaccurately interpreted. His whole edifice, built on such 

 weak foundations, falls in, the moment one carefully traces the develop- 

 ment of one single germen and its parts. 



The fluid which here becomes so important, is really nothing but the 

 intercellular substance treated of in an earlier part of this work, which is 

 only distinguished here by being much more watery, and, as it dries 

 slowly, remaining longer in the fluid condition in which it is secreted. 

 If, for example, the stigmatic papillae be observed in a perfect bud of 

 Iris florentina, these are found to be longish, very delicate cells, the 

 contents of the usual kind, with some starch granules actively circulating 

 in currents distributed over the walls. Alcohol and acids coagulate the 

 contents, as in all fresh, vegetating cells, and, as in all cells containing much 

 mucus, the contents of the cells contract into the middle of the cell in a 

 tubular form ; no internal membrane can be spoken of here.* In the 

 opening flower we find a slight secretion of mucilaginous fluid upon the 

 apex of the papilla ; this gradually increases till it forms a little cap, 

 completely enclosing the apex, and by degrees extending down until 

 it entirely covers the papilla : this is Hartig's external membrane. If 

 the papilla; are not much developed, as in the plants named by Brong- 

 niart, the secretions of the separate cells flow together, and then thus 

 form an unorganised layer on the surface of the stigma ; and even over 

 the whole wall of the canal of the style. This is the cuticula of Brong- 

 niart and Hartig, which, however, is in the earliest stage a tough, adhe- 

 sive fluid, which may be' drawn out in threads, and no membrane ; and 

 may be distinctly recognised as a secretion by its origin. In all essential 

 points it is identical with the secretion of the epidermis, and is only dis- 

 tinguished, apparently, by its chemical composition, since it contains 

 more gum and sugar, while that presents more of gelatine, and often 

 wax and resin. It is also very different in chemical nature in different 



* Hartig assumes that there are three membranes to the stigmatic papillse. Of the 

 outer I will speak presently ; the intermediate one is the true cell-membrane, but the 

 internal does not exist at all, and is only the appearance above mentioned. In his 

 " Lehrbuch der Pflanzenkunde, Heft. 4.," Hartig has applied this perverse notion also to 

 the epidermis of plants ; but, from more complete ignorance of the course of develop- 

 ment, made still greater confusion. I have already remarked on the point, that in 

 gelatinous thickening-layers, deposited gradually in the interior of the cell, the inner- 

 most is often less soluble than the rest, and, indeed, quite naturally, from the same 

 reason as the outer layer of the starch granule is less soluble than the inner, because 

 the matters contained in the cell, wax, albumen, &c , impregnate this layer, with which 

 they are always in contact. In the cases of the epidermal cell brought forward by 

 Hartig, the outer membrane is the actually original cell-membrane ; all the rest are 

 subsequently deposited layers of increment, of which the innermost is merely less solu- 

 ble on account of the matters which have penetrated it, and naturally behaves in a 

 <lififerent way from the rest to solvents and reagents. 



