118 Conjectures respecting the Causes of double Flowers, 



Of the ill effects resulting from this kind of ignorance much 

 might be said. I will only, however, remark that, as it must be 

 evident, from the diversity in the habits, times of appearance, &c., 

 of these various kinds of insects, equally various must also be the 

 modes of treatment to be pursued for their respective extirpation, 

 for which the treatment for the destruction of the wire-worm 

 would not be the most efficacious ; and, further, that I trust suf- 

 ficient has been said to show the advantages of obtaining some- 

 thing like an acquaintance with the domestic manners of these 

 obnoxious insects, which it is the especial object of this series 

 of articles to extend as widely as possible. 



Art. II. Conjectures respecting the Causes tvhich produce double 

 Flotoers in Plants ; together "with the Results of some Experiments 

 made with a View to the same Object. By James Munro, Forester 

 to the Marquess of Northampton, at Castle Ashby, Northampton- 

 shire. 



Of the various phenomena which Nature exhibits in her 

 economy of the vegetable kingdom, the cause which produces 

 double flowers, and other singular varieties of plants, is, perhaps, 

 least understood by horticulturists. Different reasons have been 

 assigned for the presence of this lusus naturcB among vegetables; 

 but, when even these theories have been subjected to a practical 

 test, disappointment has followed. 



The prevailing opinion, in earlier times, rested on the theory 

 of contact; in other words, that double-flowering plants were 

 a result from single and double plants of the same kind growing 

 near to each other ; an erroneous assumption, that double flowers 

 possess impregnative qualities. Any person, possessing the 

 slightest knowledge of the sexual system of plants, knows that 

 double flowers are destitute of the productive organs; conse- 

 quently, no seed can be obtained from plants of this description : 

 they are anti-natural, and are occasioned by some infringement 

 of the laws which regulate the vegetable economy. How, then, 

 is it possible that plants thus physically incapacitated for self- 

 reproduction, by seminal process, can influence the character of 

 their neighbours by the mere circumstance of proximity ? Be- 

 sides, the unalterable relation of the order of cause and effect is 

 fatal to this theory ; for, if the agency of double flowers is re- 

 quired to alter the quality of single-flowering plants of any 



mould, and picked off the worms, they then returned the mould to its former 

 position. As many as fifty worms have been taken from one turnip." 



Mr. Spence adds, upon this fact (so strikingly corroborative of the views 

 as to hand-picking, advanced so often in this series of articles), that, at three 

 halfpence per hundred, the 18,000 cost 1/. 2s. 6d. ; a sura well expended for 

 saving an acre of turnips worth from 5/. to 7/. 



