BEES AND FLOWERS, 



475 



Figure 3 shows the dotails of an orchid: The o-reat lip (/) of the 

 corolhi ends in a h)ng- spur which inck)ses the nectar-producing 

 organs (n). Near the front of the spur the style expands into 

 a double stigma, Avhicli hangs beneath the one large anther ((>). 

 Instead of being a diffused dust, the grains of pollen are closely con- 

 nected and form two masses (po), which are joined by the stipes ('■) 

 to a glutinous body (//•) at the entrance of the spur. Excejit the 

 Oplirys ap'/frrii, which, thaidvs to a sj^ecial structure, can do so. the 

 plants of this family are utterly incapable of self fertilization. 

 Nor can the wind aid them. The pollen grains can easily l)e lifted 

 up with a needle or pencil point from the glutinous mass \vhere they 

 are collected. It is by an analagous process that honey bees effect 

 the cross-fertilization of these plants. On entering the s])ur in 

 search of nectar they come into contact with the ^'iscous disk (A) 

 and generally carry off' one oi- two of the ])ollen grains attached 

 somewhere on the front portion of their body. As Darwin has 

 shown, the sticky substance dries very quickly and when tli(» insect 



1 „ 2 



Fig. 4.— Transportation of orcliid i)ollcn iiuissos ny hoes. iPoUimi i'('i)rcsmitcil by diiiLCoiuil 



lin.'s. ) 

 1. FaiJciiui <llriil<U,it<t. 'i. KiKilusga rordiita. 



enters the spur of another flower the mass is abandoned so that it 

 becomes attached to the stigma, where it yields the fertilizing element. 



The part that the insects play and the advantages of cross-fertiliza- 

 tion among the orchids are shown with all possible cleai'ness iu tlie 

 case of the vanilla. In Mexico this j)lant is fertilized naturally l)v 

 different insects, es})ecially by the j\h'li])ones. wliich greatly resemble 

 our bees, but in other regions ai'tilicial fei'tilizat ion is lu-odiiced by 

 rubbing the stamen on the |)istil with a needle. JNI. Lecomte. who 

 has studied the matter, atti'ibutes the superior (piality of the ^Mexican 

 vanilla to the advantage of natural cross-fertilization ovei- ai'tificial 

 auto-fertilization. In our own gi-eenhouses the \anilla plant has the 

 same -experiences — it can pi-oduce {lowers, but no seed, without pre- 

 liminary fei'tilizat ion. 



We must therefore conclude that the Anthoi)hila. and particularly 

 the Mellifera, have a ])lace of no small imi)ortance in the hu'tiliza.tion 

 of ffowering })lants. 'Iliey give them the adx'antages of crossing, and 

 in a large numl)er of cases are absolutely essential to their rei)ro- 

 duction. 



