Ladies' Slippers. 85 



tile anthers producing pollen grains, which are not united into 

 waxy masses, nor tied together by elastic threads, nor furnished 

 with a caudicle as in other orchids, but are immersed in, and 

 coated by, viscid fluid, which is so glutinous that it can be 

 drawn out into threads. ' ' As the two anthers stand behind and 

 above the lower convex surface of the stigma, it is impossible 

 that the glutinous pollen can get to this, the fertile surface, 

 without mechanical aid. An insect could reach the extremity 

 of the labellum, or the toe of the slipper, through the longitu- 

 dinal dorsal slit ; but according to all analogy, the basal por- 

 tion in front of the stigma would be the most attractive part. 

 Now, as the flower is closed at one end, owing to the toe of 

 the labellum being upturned, and as the dorsal surface of the 

 stigma, together with the large shield-like rudimentary anther, 

 almost close the basal part of the medial slit, two convenient 

 passages alone are left for an insect to reach with its proboscis 

 the lower part of the labellum — namely, directly over and close 

 outside the two lateral anthers. If an insect were thus to act, 

 and it could hardly act in any other way, it would infallibly get 

 its proboscis smeared with the glutinous pollen, as I found occur 



with a bristle thus inserted Thus an insect would place 



either the flower's own pollen on to the stigma, or, flying away, 



would carry the pollen to another flower We thus see 



how important, or rather how necessary, for the fertilization of 

 the plant is the curious slipper-like shape of the labellum in 

 leading insects to insert their probosces by the lateral passages 

 close to the anthers." Glutinous pollen grains, so peculiar to 

 the Cypripediums that they alone possess them, are equally 

 essential to this scheme of fertilization, and thus Mr. Darwin 

 winds up by remarking, that ' ' there is no superfluity in the 

 means employed." 



The cultivation of Cypripediums is, generally speaking, 

 a most easy matter. Indeed 0. insigne is the best of all plants 

 for beginners in orchid culture, as it at once furnishes a key to 

 many of the peculiarities of orchids, and adapts itself to various 

 degrees of good and bad treatment. A shady position in a 

 warm greenhouse, the soil to be a mixture of peat, loam, and 

 silver-sand, and plenty of water in the season of its growth, 

 are the conditions most conducive to its well-being. The stove 

 kinds require only the ordinary treatment of what are called 

 Indian orchids — that is, a temperature varying from a day maxi- 

 mum of 65° in winter to a day maximum of 90° in summer, 

 and a night minimum of 60° in winter to a night minimum of 

 70° in summer, to be kept moist at all seasons, and when in 

 active growth to have abundance of water. The hardy species 

 are so difficult to grow that even in botanic gardens, and in 

 places where all the resources of art and fortune are at com- 



