NEPENTHES. 



251 



As in the pistillate flowers the perianth segments are four in 

 number but coloured reddish brown instead of green (fig. 58, 9 

 and 10) ; above them is the four-celled superior ovary, on the 

 upper end of which is seated the four-lobed stigma, the style of 

 the pistil being altogether absent (fresh racemes of flowers kindly 

 lent by Dr. Bailey Balfour, Mr. F. W. Moore, and Mr. George 

 Wythes, &c, here pointed out). The structure of the flowers of 

 Nepenthes is therefore extremely simple, and the manner in which 

 fertilisation is effected may be seen at a glance. 



Fertilisation. — In the wild state fertilisation is effected 

 by aerial agency ; the structure of the flowers favours this mode 

 in every way ; the staminate flowers are produced in much larger 

 numbers than the pistillate ones ; the quantity of pollen even in 

 a single raceme is great, and in the aggregate where many 

 racemes or panicles of flowers are ready to discharge their pollen 

 it must, relatively speaking, be enormous, leaving a large margin 

 for the inevitable waste which occurs when wafted through the 

 air. On the other hand, the pistillate flowers have their stigmas 

 fully exposed ; no obstacle is therefore interposed to prevent the 

 minute pollen dust being caught by the viscid surface as it is 

 carried along by the wind. 



With us pollination is effected by simply dusting the stigma 

 with pollen removed from the anther by a camel-hair pencil. In 

 the warm and moist temperature of the stove the pollen grains 

 begin to emit tubes in a very short time, and as they have no 

 style to traverse they soon reach the numerous ovules. Fig. 58, 1 2 

 shows a transverse section of an ovary, and fig. 58, 13, two 

 unfertilised ovules greatly enlarged. The precise time taken by 

 the pollen tubes to reach the ovules has not been ascertained, 

 but that it is not long is evident by the external change observ- 

 able in the ovaries within a fortnight after pollination. The 

 capsules and seeds figured are those of Northiana (fig. 58, 14 and 

 15), the flowers which produced them were fertilised in the first 

 week of October of last year, and the capsules were matured early 

 in the following January, or in about three months after pollina- 

 tion and during the winter season. As we know that in the 

 summer months the capsules arrive at maturity in a somewhat 

 shorter period, it is safe to assume that such is the case also in 

 the wild state. 



The number of seeds in each capsule ripened under cultiva- 



H 2 



