HOW PLANTS LIVE AND WORK. 333 



now occupies the position in front of the honey-tube. A bee visit- 

 ing the flower at this stage is certain to leave some pollen on the 

 stigma if it has recently left a flower in the first or male condition. 

 The flower has a series of Hues on the petals to guide the insect 

 to the honey-tube, and the lower petals are provided, in addition, 

 with a number of pointed processes which keep the rain out of the 

 spur. Their situation also possibly makes it uncomfortable for 

 the bee to stand in any other position than that which ensures that 

 its breast comes in contact with the anther or stigma. 



Only in comparatively few plants do the pistils mature before 

 the anthers, but one of these cases is so extremely interesting that 

 I must mention it. What is generally called the " flower " of the 

 Cuckoo-pint or " lords and ladies," consists of a big curled leaf 

 with a purple rod sticking up in the middle. Near the bottom of 

 the rod, but, hidden from sight by the lower part of the leaf, the 

 blossoms arise. The chamber containing the blossoms is shut in 

 by a series of stiffish hairs which point downwards Below these 

 the rod supports a series of anthers, and, near the bottom of the 

 chamber, a number of pistils. On cutting open the chamber one 

 nearly always finds a lot of midges, covered with pollen which 

 they have brought from another "flower." The midges get in 

 easily enough, but once in they are prisoners, for the down-pointing 

 hairs prevent them from getting out again. The pistils near the 

 bottom of the rod ripen and are fertilised by the pollen the midges 

 have brought. After a time the anthers above ripen, and shed 

 their welcome pollen on the hungry captives. Soon after this, the 

 hairs at the top of the chamber shrivel up, and the midges, once 

 more covered with pollen, are at liberty to return to the outer 

 world, and, untaught by experience, to repeat the experiment on 

 another " flower." Cases where self-fertilisation is prevented by 

 the difference in the times of maturity of stamens and pistils are 

 very numerous, but the examples I have given are sufficient to 

 show how effectual the device is. 



Let us now return to our Primrose. In the first section it was 

 asked, "Why have some Primroses long pistils and others short 

 ones ? " There are two kinds of Primroses, known to country 

 children as " pin-eyed " and " thrum-eyed " respectively. In a pin- 

 eyed Primrose the pistil is long, and the stigma, looking somewhat 

 like the head of a pin, is at the top of the corolla-tube, while the 



