our conservatories are the Cypripediums ; there are at least 

 a dozen s|)ecies having as pure a green color as the general 

 foliage of plants, except that one or more petals may be 

 relieved by a slight blending with another tint which Nature 

 adds to lessen their homeliness, and at the same time to 

 make them more attractive to the insects which visit them 

 and assist in their fertilization. 

 C. longifolium is wholly green. 



G. insigne: the green dorsal sepal which stands cons[)ic- 

 uously erect is tipped for a third of its length with 

 pure white. 

 C Harrissianum : the veins of the dorsal sepal, which is 

 largely white, and also of the sli})per or tubular lower 

 petal, are turned to a dull purple. 

 C. Lawrenceamim : the dorsal sei)al has become quite 

 white l)y the fading out of the green, except that 

 there remains a few streaks with the purple veins. 

 There is moreover a variety of C caUosiwi in which the 

 whole tlower is of the purest white, saving the green veins. 

 C. Charles worthii: the whole dorsal petal has changed 



from white to a beautiful i)uik purple. 

 C. Sedenii and C. Calurum have all the petals of a rose 



color, only a trace of green remaining. 

 The green portions of these tlowers by age become yel- 

 lowish, for orchids as a rule remain fresh for a month or 

 six weeks. Green flowers often become yellowish-green or 

 greenish-yellow and finally pure yellow ; and among the 

 Cypripediums are found [)ure yellow varieties. 



One can therefore trace from the foundation green, a 

 white, a purple, a rose, and a yellow, and an iiitinite num- 

 ber of shades and tints. The purples and reds are evi- 

 dently separate and independent colors, breaking through 

 the chlorophyl green. 



Yellow often results from the disintegration or dissolution 

 of the chlorophyl itself, which is largely composed of 

 yellow with some I)lue. White results from the loss of 



