- 10 - 

 Laelia anceps Lindl. 



The petals and sepals in this species are of a vivid lilac rose color. 

 The elongated lip has in front a reddish purple spot and is ornamented in the 

 interior and in the throat with dark red stripes. 



If one examines all these colored parts of the flower, one will find 

 almost always that the pigment to which they owe their color is diffused in 

 the cell sap ;in inquiring into its origin one should examine the sparse 

 red spots of the gynostemium, which are of late formation. 



Such spots are due to a group of epidermal cells each one of which con- 

 tains a single cyanoplast (Pl. XVI, fig. k) . This cyanoplast is found im- 

 mersed in the cytoplasm. In its adult stage it is of dimensions comparable 

 to those of the nucleus, is reddish purple in color, has no definite position, 

 and presents an involucre in which is included a colored substance which 

 presents all the characteristic reactions of anthocyanine . In fact, this 

 pigment is soluble in alcohol and especially in acidulated water, becomes 

 green with nicotine and greenish yellovi; with alkali. It decolorizes easily 

 with oxidizing substances. 



On the other hand, the presence of an involucre in the cyanoplast 

 may be demonstrated through the use of 50 per cent alcohol, i per cent 

 hydrochloric acid solution, 1 per cent solution of acetic acid, i per cent 

 solution of chromic acid, and, above all, by oxygenated v;ater or by osmic 

 acid. By treating the sections with oxygenated water, one may set free from 

 the cyanoplast its pigment and thus place easily in evidence its involucre 

 which appears colorless as a vesicle which remains immersed in the cytoplasm. 

 Treated with osmic acid, on the contrary, the involucre becomes blackish and 

 vacuolized (PI. XVII, fig. 9). 



It is to be noted, moreover, that the above-named reagents do not act 

 for a few minutes, but, if the action is prolonged, the involucre dissolves 

 and disappears. 



