52 INTRODUCTION 



which the plant grows. The capsules of the summer-flowers are shorter and 

 thicker than those of the spring- flowers, because the upper part of the carpels 

 which is continued into the style, does not grow out into a long pointed process, as 

 it does in the latter. In each chamber there are usually four seeds, just as in 

 the fruits of the spring-flowers, and there is no difference between the seeds of 

 the two kinds of fruit. 



At the time of its full development, the summer-flower has a length of rather 

 more than one line, and its form is that of a closed flower-bud. The tip of the white 

 corolla projects a litde between the tightly closed sepals, but without making an 

 entrance to the interior of the flower. The corolla consists of five ovate petals, with 

 twisted aestivation, so as to closely envelop the essential organs. The five outer 

 stamens are about half as long as the ovary, and their anthers are extremely small ; 

 the five inner stamens possess far larger anthers, and some of them attain the length 

 of the ovary, while others are rather shorter than this. The five very short styles 

 are therefore situated either right in the middle of the larger anthers, or project 

 a litde beyond them. The small size (i/Sth-i/pth line=o-2 1-0-25 itiki-) of the 

 inner anthers is associated with a correspondingly small quantity of pollen, and the 

 number of pollen-grains in each loculus may not exceed two dozen, while in the still 

 smaller anthers of the outer stamens there are not more than a dozen. In spite 

 of the relative fewness of the grains in comparison with other flowers, the amount 

 of pollen is really not inconsiderable in relation to the number of the ovules to 

 be fertilized, having regard to the fact that owing to the complete closure of the 

 flower none of it can be lost, and considering how fertilization is furthered by 

 the proximity of anthers and stigmas. The pollen-grains are not dehisced, but 

 germinate while still enclosed in the anthers. The pollen-tubes grow out in an 

 irregular tangle from both sides and from the tips of the anthers. They creep here 

 and there among the anthers and styles, and for the most part climb up the latter to 

 reach the small sdgmas. The anthers are bound together and united with the 

 stigmas by the pollen-tubes. 



The process of fertilization appears to be quickly accomplished, for com- 

 paratively few flowers are found in the stage of development just described. When 

 the corolla, still closely twisted, protrudes more obviously beyond the tips of the 

 sepals, owing to the swelling up of the ovary, the anthers are already withered, 

 and hang from the stigmas, having been detached from the persistent filaments. 

 If the anthers are softened and opened at this stage, the pollen-grains will still 

 be found enclosed in them. 



In Impatiens Noli-tangere the arrangements are very like those of Oxalis 

 Acetosella. At the time of their full development the small flowers have the form 

 of a closed, elongated bud about one line (about 2^ mm.) in length, the upper part 

 of the closely overlapping sepals, which projects beyond the sexual parts, being 

 contracted into a relatively thin, blunt, conical process. The petals in the form 

 of whitish scales of the same length as the pistil, and the anthers, which are 

 carried on relatively long filaments, are inclined towards one another, so as to 

 form a hood above the pistil, but they are not united to one another. When the 

 ovary elongates after fertilization, it carries up the whole united mass of sepals, 

 petals, and stamens in the form of a small cap, like the calyptra of a moss capsule. 



