GEITONOGAMY. 827 



pallen by insects occurs but seldom in this plant, so that from the many ovark-s in 

 the inflorescence of Eremurus usually only a few fruits are matured. This is the 

 more remarkable as these flowers have remarkably long-livr<l stigmas, a peculiarity 

 which is generally very advantageous in bringing about cross-pollination. The 

 stigma is already mature when the perianth opens; when the tips of tin- p-rianth 

 roll back and assume the form of aphides (see p. 171), and wlu-n tin- style mo 

 like the hand of a watch towards the axis of the inflorescence, the stigma is still 

 receptive, and remains so even when the style has again straightened and assumed 

 an oblique upward direction. 



A peculiar instance of geitonogamy is observed in A Ilium Victorialis. Each umbel 

 is composed of flowers of very different ages. Before the first flowers bci 

 wither, and shrivel up, their pollen- covered anthers project well over the edge of the 

 perianth. In the younger flowers, at the same time, the anthers are still closed and 

 covered by the perianth-leaves, but the stigmas are ripe and project beyond them. 

 These young and hitherto short-stalked flowers are now raised by the elongation of 

 their pedicels and inserted between the older flowers, so that, as a matter of course, 

 their stigmas are brushed by the pollen of the older flowers, if it does not indeed fall 



on them. 



The geitonogamy in the Bistort (Polygonum Bistorta) is very strange. 

 rendered rather complex, as a peculiar distribution of the sexes is combined with a 

 pronounced dichogamy and a peculiar way of opening. The inflorescence, which 

 looks like a spike, is really composed of numbers of tiny two-flowered groups 

 crowded together. One of the two flowers of each little group is long-styled i 

 truly hermaphrodite, while the other contains a short style, well-formed 

 and a rudimentary ovary which develops no further. It is therefore a ps< 

 hermaphrodite staminate flower. In each group the long-styled hermaph 

 flower opens first, beginning at the base of the apparent spike and g 

 working up to the top. The staminate flowers do not get their turn t 

 highest of the long-styled flowers has opened; but after this they behave 



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