ME. A. W. BENNETT ON CLEISTOGAMIC FLO WEES. 269 



Notes on Cleistogamic Flowers ; chieflVof Viola, Oxalis, and 

 Impatiens. By Alfeed W. Bennett, M.A., B.Sc, F.L.S., 



Lecturer on Botany at St. Thomas's Hospital. 



[Bead November 7, 1878.] 



The most important records of observations hitherto made on the 

 closed self-fertilized flowers which some plants possess are those 

 by D. Miiller in the ' Botanische Zeitung ' for 1857, by Micha- 

 let in the ' Bulletin de la Societe Botanique de France ■ for 1860, 

 by Von Mohl in the < Botanische Zeitung ' for 1863, and by M. 

 Kuhn in the same journal for 1867. These and some other scat- 

 tered notes are admirably summarized, and supplemented with 

 some observations of his own, by Mr. Darwin, in the last chapter 

 of his c Different Forms of Flowers on Plants of the same Species f 

 (1877). I am not aware, however, that, with the exception of my 

 paper on the closed self-fertilized flowers of Impatiens fulva, the 

 -Euglish reader has access to any original drawings of this inter- 

 esting class of flowers. This, and the important bearing on the 

 laws of the fertilization of flowers of any addition, however slight, 

 to our knowledge of the structure and function of these flowers, 

 must be my excuse for bringing the following imperfect notes 

 before the Fellows of the Linnean Society. My observations on 

 Viola sylvatica, Oxalis Acetosella, and Ijppatiens noli-me-t anger e 

 were made on wild specimens gathered in August and September 

 in a mountainous part of Wales ; those on the other species of 

 Viola and Impatiens on specimens from the Botanic Gardens at 

 Kew and in the Kegent's Park, during September and the early 

 part of October of the present year (1878). 



Viola. 



V-jucullata, Ait. (North America).— This common North- 

 American violet produces through the autumn abundance of cleis- 

 togamic flowers on long erect pedicels springing from near the 

 crown of the root. They are fully one third of an inch in length, 

 the largest I am acquainted with in any species of violet, and 

 exceedingly favourable for observation. I have had but little 

 opportunity of observing their fertility, and comparing it with that 

 of the perfect vernal flowers. The calyx consists of five nearly 

 equal, linear-lanceolate, slightly auricled sepals, which are imbri- 

 cate, and never open, even at the tip, until the growth of the fer- 

 tilized capsule forces ther* apart. The corolla is, as far as I could 



ttVff. JOUBN. — J50TAJST, VOL. XTII. * 



