AND CR08S-FEBTILIZE THEIR FLOWERS. 



27 



55. The peciiliarities are mainly these : 

 First, the better to attract certain insects 

 and repay them for their service, a sepa- 

 rate organ for the nectar — in this in- 

 stance a long pouch or honey-tube — is 

 attached to the flower. Then, to econo- 

 mize the pollen, the whole of it in each 

 cell of the anther is done up in little 

 packets or coarser grains, which are tied, 

 as it were, to each other by delicate 

 elastic threads, and all made fast by 

 similar threads to the upper end of a 

 central stalk. Finally, to make sure of 

 its being taken by the insect and not 

 dropped or lost in the carrying, the 

 other end of this stalk bears a flat disk, 

 commonly button-shaped, the exposed 

 face of which is very sticky ; and this is 

 placed just where it will be pretty sure 

 to be attached to the head or proboscis 

 of an insect that comes to drain the 

 honey-tube. So that the insect, on ris- 

 ing from his meal, will probably carry off 

 bodily the whole pollen of that flower 

 (or of one of its anther-cells), and be- 

 stow it, or some of it, upon the next 

 flower or flowers visited. 



56. In this particular species, the front 

 petal is, as usual, the insect's landing- 

 place. The other petals are more arch- 

 ing than the front view of the flower in 

 Fig. 16 represents, and obstruct access 

 on all other sides. The long and narrow 

 front petal turns downwards and allows 

 convenient approach. Underneath hangs 



Fig. 16. Flower of Greater Green Orcbis (Habenaria 

 orbiculata). IT. Its stamen and stigma more enlarged. 

 18. One of the pollen-masses with its stalk and disk, 

 equally enlarged. 19. Its^disk and a part of the stalk 

 more magpified. 



