30 6 Leake . — The Localization of the Indigo-producing 
do the vascular bundles, with the exception of the midrib. In the vascular 
bundles indigo is deposited in all elements except the xylem-vessels. 
In the older and fully-developed leaves the larger veins, in addition to the 
midrib, remain colourless on treatment. 
IV. Phajus GRANDIFOLIUS, Lour. 
As early as 1830 this plant was recognized by Clamor Marquart to 
yield indigo (16). Reference has already been made to the work of Goppert 
and Miiller-Thurgau (3 and 4), whose methods need not be recapitulated 
here. According to the former the localization in the flower is the same as 
in Calanthe : ‘ das Labellum der Bltithe und Operculum am dunkelsten, 
wahrend die Pollenmassen, aber diese nur allein, ihre natiirliche gelbliche 
Farbe . . . behalten 5 ; the flower, stalks, and bracts become blue, as do also 
the leaves. Muller-Thurgau only deals with the petals, the labellum in 
particular, in all of which he finds indigo deposited. 
The distribution was next investigated by Molisch (5), precipitation 
of indigo being obtained by exposure to alcohol vapour. Briefly, he 
localizes indigo as follows : — 
‘Wurzel. Die relativ grosste Menge von Indican findet sich in den 
Meristemzellen der Spitze und in 1-3 Zelllagen knapp unterhalb der 
Wurzelhulle (Velamen). In den Wurzelhaaren, dem Velamen und dem 
ubrigen Wurzelparenchym sehr wenig, nur Spuren in einzelnen Zellen des 
centralen Gefassblindelcylinders. 
£ Der Stengel und die knollenformigen Verdickungen (Scheinknollen) 
desselben fiihren reichlich Indican. 
£ Blatt. In der Epidermis wenig, im griinen Parenchym viel, im 
Gefassbiindel nur Spuren des Glykosids. 
‘ Bliithe. Alle Theile, und zwar nahezu alle Zellen mit Ausnahme der 
Pollinarien indicanhaltig/ 
Repeating his experiments in 1899 (8) he localizes the blue more 
particularly in the mesophyll, and especially the chloroplasts, of this tissue. 
The vascular bundles and epidermis, with the exception of the guard-cells, 
remain colourless to the eye, while the hairs, sieve-tubes, and raphide-cells 
contain no indigo. 
Beijerinck, on the other hand, obtains blue depositions in the meso- 
phyll and epidermis by boiling a section in hydrochloric acid and ferric 
chloride (10). 
Only the aerial vegetative organs — the leaves and pseudo-bulbs — have 
been examined by the sulphuric-acetic-persulphate reagent. By this means 
the blue is deposited in the cell-plasm as very minute granules, the smaller 
of which are difficult to identify as such, even under the high powers 
of the microscope. 
