CLEISTOGAMY 



53 



At the time of fertilization the ovary is 0-7 5-0-8 of a Hne (about 2 mm.) in 

 length, and crowned by five very short conical pointed styles, ending in punctate 

 stigmas. The anthers have a triangular connective, with apex above, over which 

 the small loculi (0-24 of a line in length) project. The number of pollen-grains 

 developed in each loculus does not exceed forty, or at most fifty. They are 

 ovoid, about 0-015 of a line in length, and o-oi of a line in breadth (=0-03 

 and 0-02 mm.), and are colourless. Ahhough the anthers dehisce markedly, 

 the pollen-grains escape no more than they do in Oxalis, but, as in the latter, 

 germinate within the anthers, with the production of very numerous pollen-tubes, 

 which unite the anthers with the stigmas. These tubes are very soft, so that 

 they tear when the anthers are pulled away, without drawing the pollen-grains 

 out of the loculi. 



In Specularia perfoliata there is a small whitish mound in the basin-shaped 

 depression of the superior calyx, which, looked at through a lens, is seen to be 

 traversed by prominent radiating ridges, from which- several (some 6-12) small 

 bristles project. In this mound the stamen and styles are concealed. Their 

 number and relative position are easily recognized when the upper part of the 

 mound is removed by a transverse cut. It is then seen to be hollow, its wall 

 consisting of a very thin membrane. The stamens come into lateral contact with 

 one another above the tips of the styles. Their number corresponds to that of the 

 calyx lobes, 3-5. The number of the styles and chambers of the ovary is usually 

 two when the calyx lobes are three or four, and three when the calyx lobes 

 are five. 



The whitish membrane that forms the mound in question corresponds 

 undoubtedly to the corolla, but there is no trace of a division into separate 

 lobes or of any opening in the middle of the m.ound. The form of the cavity 

 enclosed by the corolla changes as the flower develops. In very small flowers 

 that are as yet far removed from the stage of fertilization, the corolla appears as 

 a moderately sharp cone, but this becomes more and more flattened with the 

 growth of the ovary. While the upper part of the cavity that contains the 

 stamens and style thus diminishes in size, at least relatively, the under part 

 increases, since it assumes the form of a funnel projecting into the ovary. The 

 actual size of this cavity, however, is always very limited. The filaments of the 

 stamens inserted at the periphery of this cavity are very short ; the anthers measure 

 about 0'i3''''' (about 0-3 mm.) in length. They are colourless, and contain a 

 considerable quantity of pollen-grains. These are without colour, and their 

 diameter is o-oi4'" to o-oi7''' (about o-o35-o-o44 mm.). The styles are relatively 

 thick, and of ovoid form ; their tips and their inner sides are stigmatic. There 

 is no trace of the characteristically formed collecting-hairs that are always present 

 on the outer sides of the styles of Campanulaceae. The pollen is not scattered, 

 but spreads its tubes from the anthers. They take an irregular course through 

 the space that exists between the anthers and styles, as well as laterally between 

 the anthers themselves. These organs are thus united together with moderate 

 firmness, so that their upper part can be cut away by a vertical section without 

 causing displacement. The pollen-tubes are so tough that many of them are not 

 torn across if the anthers are pulled away from the styles, but remain connected 



