Mr. J. Miers on the genera Hyoscyamus and Physochlsena. 467 



XLI. — On Hyoscyamus and Physochlsena. 

 By John Miers, Esq., F.R.S., F.L.S. 



Hyoscyamus. 



I am induced to offer a few remarks, and propose an emended 

 character for this genus, in order to confirm some observations 

 made on a previous occasion (huj. oper. iii. 174). Although the 

 opercular dehiscence of the capsule of Hyoscyamus has long been 

 notorious, the fact of a glandular enlargement on the summit of 

 the ovarium does not appear to have been anywhere described : 

 it is however a circumstance worthy of consideration in a physio- 

 logical point of view, and leads us to inquire what is its true 

 nature. In the ovarium of Hyoscyamus pictus, which I examined 

 in a living state, this glandular appendage is seen to form a very 

 distinct, thick, and fleshy covering over its larger superior moiety, 

 where it is terminated by a decided margin, and as the ovarium 

 advances towards maturity, the lower portion increases consider- 

 ably in bulk, the pericarpial envelope being drawn out to a thin 

 membranaceous tube, marked with numerous longitudinal and 

 branching nervures, while the upper thickened moiety increases 

 but little in length : these longitudinal nervures may be distinctly 

 traced upon the inner lining from the base to the summit of the 

 cell, while upon the external face they are visible only on the lower 

 portion, no trace of them being seen upon the glandular moiety, 

 which exhibits quite a different texture, proving beyond all doubt 

 that the glandular coating in question is really superimposed, and 

 forms no part of the endocarpial lining, and therefore that it is not 

 an interior secretion within the cavity of the cell. It is evident 

 that the lower half of the ovarium consists of two cohering inte- 

 guments with little or no intervening substance ; for when the 

 fruit is ripe they are seen to be really distinct, and may without 

 difficulty be separated from each other on their lacerated edges : 

 but in the upper moiety the remarkable fleshy gland before men- 

 tioned is seen to be interposed between the continuation of these 

 two integuments, and as it hardens by the deposition of woody 

 matter it constitutes the well-known operculum, which forms quite 

 an external mushroom-headed enlargement, and which falls off, 

 not by a regular dehiscence, but by a ruptured edge, as is proved 

 by the lacerated margin of the two integuments upon the cir- 

 cumscissile line. The nature and purport of this apical gland 

 do not appear manifest ; it is probably an extension from the 

 base of the style, for the epicarpial integument terminates at the 

 summit of the ovarium by a small ring, that forms an apparent 

 articulation with the style, which on the contrary is continuous 



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