188 DIFFICULTIES OF THE THEOKY Chap. VI. 



view of Nature is incrediljlo. Witli plants having' scjiarated 

 Bcxcs, and witli those in whicli, tlious-li herniaplnodites, the 

 pollen docs not spontaneously fall on tlie stig'ma, some aid is 

 necessary for their fertilization. AVith several kinds this is 

 cHected by the polli'U-yrains, which are lig'ht and incoherent, 

 Ix'ino; blown 1)y the wind through mere chance on to the stigma ; 

 and this is the simj)lest plan which can well be conceived. 

 An almost equally simple, though very different, plan occurs 

 in many plants in which a symmetrical flower secretes a few 

 drops of nectar, and is consequently visited by insects ; and 

 these carry the pollen from the anthers to the stigma. 



From this simple stage we may pass through an inexhaust- 

 ible number of contrivances, all for the same purpose and 

 cflected in essentially the same manner, but entailing changes 

 in every part of the llower. The nectar may be stored in vari- 

 ously-shaped receptacles, with the stamens and pistils modi- 

 fied in many ways, sometimes forming traj)-like contrivances, 

 and sometimes capable of neatly-adapted movements through 

 irritability or elasticity. From such structures we may ad- 

 vance till Ave come to such a case of extraordinary adaptation 

 as that lately described by Dr. Crugcr in the Coryanthcs. Tliis 

 orchid has jiart of its labellum or lower lip hollowed out into 

 a great bucket, into which drops of almost pure water contin- 

 ually fall from two secreting horns which stand above it ; and 

 v.hen the bucket is half full, the water overflows by a spout 

 on one side. The basal part of the labellum stands over the 

 bucket, and is itself hollowed out into a sort of chamber with 

 two lateral entrances ; Avithin tliis chamber there are curious 

 fleshy ridges. The most ingenious man, if he had not Avit- 

 nessed Avhat takes ])lace, could never liaA^e imagined Avhat pur- 

 pose all these parts serve. But Dr. Crtiger saAV croAvds of 

 large humble-bees A'isiting the gigantic flowers of this orchid, 

 not in order to suck nectar, but to gnaAV ofi" the ridges Avithin 

 the chamber aboA^e the bucket ; in doing this they frequently 

 I)ushe(l each other into the bucket, and their wings being thus 

 Avetted they could not fly away, liut had to craAvl out through 

 the passage formed by tlie spout or OA-erflow. Dr. Crllger saw 

 a "continual procession" of bees thus crawling out of their in- 

 A'oluntary bath. The passage is narroAver, antl is roofed over 

 by the column, so that a bee, in forcing its Avay out, first rubs 

 its back against the viscid stigma and then against the viscid 

 glands of the pollen-masses. The jiollen-masses are thus glued 

 to the back of that bee Avhich first happens to craAvl out through 



