THE DEVELOPMENT OF THE OVULE OF IMPATIENS 



PALLIDA NUTT. 



ANNA HALL RAITT 

 University of Cincinnati, Cincinnati, Ohio 



The genus Impatiens is represented chiefly in Asia, where in 

 1860 a collection of 100 species was made.^ A much smaller 

 number are natives of Europe, while only two species have been 

 found in America. Impatiens pallida, Nutt. and I.fulva, Nutt. 

 are abundant in moist localities in this region. Their range is 

 from Quebec to Oregon, south to Georgia and Kansas. The for- 

 mer, I. pallida, is the species discussed in this paper. Except for 

 the work of B. Longo^ on the endosperm and the embryo, and of 

 C. Brunotte^ on the embryo, I have been able to find no record 

 of researches into the life history of Impatiens. Their work was 

 done on Asiatic and European species. This paper is an account 

 of the development of the ovule of I. pallida, in which there are 

 a few peculiarities. 



The flowering season given for /. pallida is from July to Sep- 

 tember. This is true in respect to the ordinary fertile flowers, 

 but the buds of the cleistogamous flowers appear late in May 

 and last throuugh June. A few of them may even be found along 

 with the flowers throughout the summer. These flowers resemble 

 the ordinary buds externally but grow to a length of about 2 mm., 

 the well developed stamens and pistil filling most of the space, 

 the petals being aborted. After fertihzation the capsule enlarges 

 rapidly, pushing off the dry perianth. The average number and 

 size of the seed produced by the cleistogamous flowers is the same 

 as that produced by ordinary flowers, and so far as I have deter- 

 mined, the development is identical. 



1 Hofmeister, W., Allgemeine Morphologie der Gewachse. Leipsig 1868: 462. 



2 Longo, di B., Richerche su le Impatiens. Annali di Botanica. VIII: 5. 



* Brunotte, C, Sur L' Ovortement de la racine principale chez una espece du 

 genre Impatiens. Comptes rendus, avril, 1896. 



195 



