134 THE STOBY OP THE PLANTS. 



flowers clustered, as in cuckoo-pint, on a thick 

 club-stem, and they have an open spathe, which 

 more or less protects them. Our English sweet- 

 sedge is still at this stage of evolution. The 

 marsh-calla of Northern Europe and Canada, on 

 the other hand, has a handsome white spathe to 

 attract insects, while its separate flowers, still 

 both male and female together, have each six 

 stamens and a single ovary. But they have lost 

 their perianth. The common whitv^, arum or 

 "calla lily" of cottage gardens has a bright 

 yellow spike in its midst, and if you look at it 

 closely you will see that this spike consists 

 entirely of a great cluster of stamens, thickly 

 massed together. The top of the spike is entirely 

 composed of such golden stamens, but lower 

 down you will find ovaries embedded here and 

 there among them, each ovary as a rule sur- 

 rounded by five or six stamens. Lastly, in the 

 cuckoo-pint the lower flowers have lost their com- 

 plement of stamens altogether, while the upper 

 ones have similarly lost their ovaries ; moreover, 

 a few of the topmost have been converted into 

 the curious lobster-pot hairs which assist, as I 

 have shown you, in the w^ork of fertilisation. 

 We have here a singular and instructive example 

 of what may be described as retrograde develop- 

 ment. 



And now we must go on to those modes of 

 fertilisation which are effected by agencies other 

 than insects. 



