U iim.wiy i:\ im BENDING OF THE PISTIL. 



351 



Balad ( ValerianeUa Awricvla, 7. carinata, fee), and of the non-twining species of 

 Honeysuckle (Lonicera alpigena, /.. nigra, /.. Xylosteum) are protogynous, and the 



stylo is so placed when the corolla opens that its stigma must of necessity he brushed 

 by insects as they make their way to the receptacle. There is evidently at this stage 

 no possibility of any but cross-fertilization. Later on, when the anthers open and 

 expose their pollen, the stigma is taken quite out of the way, the style becoming 

 h.iii downwards or to one side, so that the stigma cannot come into contact with 

 anthers of the same flowers either spontaneously or through the agency of insects. 

 Xot till the flowering period is nearly over does the style return to its original 

 tion; when this happens, the stigma is raised by the straightening up of the 

 style, and is pressed against the anthers, which are still coated with pollen. The 

 flowers of the Martagon Lily (Lilium Mariagon) are nodding, and have their 



Fig. 299.— Autogamy effected by means of an inflection of the style. 



i I : \\ er of Tricyrtes pilosa in the first stage of its development. 2 The same in the last stau-e of development 3 Flnwer of 



iforina Pergica in the first stage of development * The same in the last stage of development. s Stigma of Marina 



red with pollen from anthers belonging to the same flower. •> Flower of Euphrasia minima in the first st:iu<^ of 



development. • The same in the last stage of development. All the figures slightly magnified. In figs. 2, 3, * t 6 a „,i : || U . 



front part of the flower is cut away 



perianth-lobes strongly reflexed. In each petal there is a groove which is roofed 

 over and closed in the middle by two coalescing rims, so that the honey stored in 

 the groove can only be sucked out by insects at the two extremities where the 

 groove is open. The flowers are protogynous, and, when they are newly open, the 

 style is straight and holds its stigma in such a position that it is sure to be touched 

 by insects sucking honey from the inner orifice of the groove. As the anthers are 

 still closed at this stage, only foreign pollen can be affixed to the stigma. Subse- 

 quently dehiscence ensues, and the position of the anthers in front of the externa] 

 orifice of the groove ensures their pollen being brushed off by insects trying to suck 

 the honey at that end, whilst the stigma is left untouched by them. In this second 

 stage of the flower's development the style begins to bend a little to one side, and, 

 towards the end, the curvature increases to such an extent that the stigma comes 

 into contact with one or sometimes two of the anthers, and dusts itself with pollen. 

 Often enough, it is true, the stigma misses its mark, and in consequence autogamy 

 is not so certain to occur in the Martagon Lily as in most of the other cases. It 



