AND CROSS-FERTILIZE THEIR FLOWERS. 35 



69. One might douht whether such movements as those of the stamens of Bar- 

 berry and of Kalmia were really intended for the use here assigned to them. 

 But they serve this purpose, unquestionably, and we can think of no other. Now 

 there is a flower of a tropical Orchid, cultivated in some conservatories (named 

 Catasetum), in which a movement under irritation (analogous to that of the Bar- 

 berry-stamen) and one of elasticity (like that of Kalmia) are combined in one 

 apparatus, — one so elaborate and special that nobody can doubt that it is a con- 

 trivance for this particular purpose. It cannot well be described here without 

 numerous figures and much detail. But the amount of it is, that a sensitiveness 

 of two slender and partly crossed arms, which the moth or other large insect must 

 hit in reaching the flower-cup, liberates a pollen-mass which is set as a spring, and - 

 lets it fly. like a catapult ; it hits the head of the insect at some distance, disk-end 

 foremost, and sticks fast to it, in proper position to be applied to the stigma of the 

 next proper flower visited. 



70. Returning to flowers of ordinary structure, and of familiar kinds, two par- 

 ticular arrangements for insuring cross-fertilization in perfect flowers must be 

 briefly noticed. The commonest is that of 



71. Dichogamous FlowcrSi Bichogamy is the name given to the case in which 

 the stamens and the stigmas of the same blossom come to perfection at different 

 periods. That is, the anthers mature and discharge their pollen in some plants . 

 before the stigma is ready to receive it, in others only after the stigma has with- 

 ered. Either way, the pollen that fertilizes and the stigma that is fertilized can 

 never belong to the same blossom. 



72. In the Common Plantain of our dooryards and waysides, Plantago major, and 

 in the English Plantain, or Ripple Grass {P. lanceolata) of the fields, this is famil- 

 iarly illustrated. The style projects from the apex of the closed bud, ready to 

 receive pollen from other flowers a day or two before its stamens are hung out 

 upon their slender filaments, to furnish pollen for other flowers, — not for their 

 own, the stigma of which is by that time dried up. Plantain-flowers, however, 

 produce no nectar, and are neither fragrant nor brightly colored ; so they are not 

 visited by insects, but are left to the chance of the conveyance of the pollen by 

 the wind. It is the same with many Grasses and Grains, only in reverse order. 

 Their anthers hang out on their slender filaments one morning, and the feathery ~ 

 stigmas of that blossom not until the next morning ; and the wind is the pollen- 

 carrier. 



