M. E. Regel on Parthenogenesis. 103 



The author of this notice has expressed^ iu the last year or two 

 (' Bonplandia/ 'Gartenflora'), his modest doubt as to the accuracy 

 of the experiments of Naudin and Decaisne, which served as the 

 basis of hypotheses of such great weight. 



An objection arose in the outset, from the fact that the result 

 was only obtained in small-flowered plants which developed a 

 mass of flowers in every leaf-axil, while large-flowered plants, 

 like Ricinus and Ecbalium, bore no seed when fecundation was 

 prevented. Still more striking was it, that, of plants known to 

 be polygamous, only female plants were mentioned, and an 

 assurance was given that no male flowers were observed upon 

 them. 



I have in the present summer repeated the experiments made 

 by Decaisne and Naudin. Although they are not yet quite con- 

 cluded, they have afibrded me proof that Decaisne and Naudin 

 have observed but superficially, and that neither Spinacia nor 

 Mercurialis are to be included among plants which can furnish 

 proof of parthenogenesis *. 



Plants of Spinacia, Mercurialis annua, and Cannabis were 

 planted singly in potsj and the male plants were removed as 

 they appeared, before the dehiscence of the earliest anthers. 

 The female plants were kept in a place where no pollen from 

 similar plants could have access to them. As soon as the first 

 flowers were perfectly developed, they were cut away so as to 

 leave only a few axillary inflorescences which could be easily 

 examined. MX newly-produced lateral branches, which were 

 abundantly developed, were carefully removed, and the inflores- 

 cences of the plants experimented on observed daily with a lens. 

 These observations refer, up to this period, only to Mercurialis 

 and Spinacia, as Cannabis has not yet unfolded any flowers. 



Mercurialis. — One of the female plants was placed in a dif- 

 ferent locality, where it grew freely without being cut. This 

 plant has now set abundance of fruit, which will doubtless bear 

 perfect seeds with embryos. But on examination it was found 

 that solitary perfectly developed male flowers were produced in 

 the axillary tufts of flowers, as can be testified by MM. Kor- 

 nicke, Rach and Maximowicz, to whom I showed them. How 

 this escaped the observation of MM. Naudin and Decaisne, is 

 beyond my comprehension. 



Two plants of Mercurialis were cut in and observed in the 

 above described manner. Each of the few tufts of blossom pro- 

 duced a great number of female flowers. Here, again, solitary 

 male flowers continually made their appearance, so that I have 

 already removed more than twenty of them from each of the 



* I have not yet full observations upon Cannabis ; but this will doubtless 

 furnish similar results. 



