AN ACCOUNT OF THE GENUS ARGEMONE. 825 



somewhat unnatural circumstances under which the plasmodium 

 was matured, it seems better to defer introducing a fresh name 

 until further examples are obtained. 



AN ACCOUNT OF THE GENUS AUGEMONE. 

 By D. Prain. 



( Continued frorn^). 312.) 



The differentiation of A. viexicana and A. ochroleiica is another 

 matter. It is not always easy in dried specimens to separate them 

 when the specimens are only in flower ; when, however, we have 

 fruits, it is impossible to mistake the two. Had the plants been 

 European, instead of American, there is no doubt that A. ochroleuca 

 would have received without question the rank of a species ; it is, 

 to take a familiar example, as different from A. viexicana as Papaver 

 dubium is from P. Rlueas, and though we all know how, on occasions, 

 every single differential character may break down in the case of 

 these two allied "Poppies," few of us would venture to propose 

 their formal union. Sir William Hooker has sounded a note of 

 warning against the tendency, as strong apparently in 1831 as it is 

 to-day, of uniting too readily the different forms of Anjomone, and 

 the only authors who have attempted to give a comprehensive 

 account of the genus (Otto and Dietrich in Allr/eni. Gartenzeit. i. ; 

 1833) havte kept them apart. In deference, however, to the view of 

 Mr. Lindley, I have here treated Sweet's "■ochroleuca" as only a 

 variety of A. mexicana : the duty of pror^ouncing a final verdict 

 must be left to the botanists of America, who alone have the 

 opportunities of making the study in the field that is necessary to 

 decide the point. 



The attempt made in the case of A. mexicana proper to separate 

 a small-flowered and a large-flowered form might also be made 

 within A. ochroleuca, the small-flowered form of which has been 

 named A. Barclayana. The original description of A. Barclaijana 

 is unfortunately very inadequate, aud Penny, its author, does not 

 seem to have preserved specimens; at all events, none of his are to 

 be found in the herbaria at Kew or the British Museum. But a 

 plant known as A. Barclayana continued to be grown for some 

 years after the date of publication of this form in English gardeus ; 

 fortunately one of these is preserved at Kew, and it shows us that 

 the plant so designated was that small-flowered form of ^. ochroleuca 

 which grows in Lower California, and on the opposite shores of the 

 Gulf of California, in North-west Mexico. In this case again, were 

 it possible to treat A. ochroleuca as a distinct species, we should be 

 quite justified in treating this plant as- a distinct variety, to be 

 named A. ochroleuca var. Barclayana. As before, I have refrained 

 from defining the variety in the text, so as to avoid the confusion 

 that must result from the presentation of too many diagnoses. 



Argemone mexicana was introduced to Europe in 1592, and 



