BOTANY. 291 



This is obvious from such an arrangement of the organs that the 

 pollen-mass (pollinium) and other connected parts are too closely 

 embedded to be shaken out by violence. Somehow, the precious 

 pollen must be transferred; the little grains, so reproductive when 

 properly applied, would be useless in their original position. They 

 are there with all their natural fertilizing qualities, but they must 

 be elsewhere before these can be serviceable. What is to transport 

 them if they cannot be shaken out by a gentle violence ? Try Mr. 

 Darwin's experiment, and you will arrive at his conclusion. He cov- 

 ered one plant under a bell-glass before any of its poliinia had been 

 removed, and he left three adjoining plants uncovered. Frequent 

 examinations disclosed the fact that some of the polliuia were daily 

 removed from the uncovered plants until nearly all were gone, while 

 all the poliinia remained firm in the cells of the glass-covered plant. 

 Other observations tend to a like result. From all of them it may be 

 inferred that there probably is a proper season for each kind of 

 orchis, and that insects cease from their visits to it after the proper 

 season has passed, and the regular secretion of nectar has ceased. 



The evidence of insect visitation is not derived from their detection 

 in the flowers ; and it is a curious circumstance that, although Mr. 

 Darwin has been in the habit for twenty years of watching orchids, 

 he has never seen an insect actually visit a flower, excepting, in- 

 deed, some butterflies on two occasions. We are to look for the evi- 

 dence of their visitations, not by attempting to detect the insects in 

 the act, but by discovering the stolen goods, the poliinia, upon their 

 bodies. This Mr. Darwin has especially observed in the case of 

 moths, who are attracted, with other insects, by the peculiarly sweet 

 nectar secreted by the orchis flowers. 



The nectar-secreting apparatus in some species is very curious. In 

 one species, the Coryantliis, two little horns near the straplike junc- 

 tion of the labellum with the base of the column secrete so much 

 limpid nectar, having a slightly sweet taste, that it slowly distils, and 

 a single flower will in all secrete about an ounce weight. The most 

 remarkable appendage is that of the deeply-hollowed end of the label- 

 lum, which hangs some way down, exactly beneath the two little 

 horns, and catches the drops as they fell, precisely like a bucket sus- 

 pended some way beneath a dripping spring. 



In fact the arrangement for seducing the insects to visit and alight 

 upon the flowers is in some cases so ingenious that Mr. Darwin, in 

 describing it, exclaims : " A poet might imagine that whilst the pol- 

 iinia are borne from flower to flower, adhering to a moth's body, they 

 voluntarily and eagerly place themselves, in each case, in that exact 

 position in which alone they can hope to gain their wish and perpetu- 

 ate their race." 



The special adaptation of parts for the fertilization of Listera ovata 

 is clearly unfolded, and worth attentive study: "The anther-cells 

 open early, leaving the pollen-masses quite loose, with their tips rest- 

 ing on the concave crest of the rostellum. The rostellum then slowly 

 curves over the stigmatic surface, so that its explosive crest stands at 

 a little distance from the anther ; and this is very necessary, other- 

 wise the anther would be caught by the viscid matter, and the pollen 

 forever locked up. This curvature of the rostellum over the stigma 



