3oi 
Substance in Indigo-yielding Plants . 
tropical climates, have received less attention than the corresponding 
species of various other genera which are either cultivated in temperate 
climates ( Isatis and Polygonum) or are commonly met with under artificial 
conditions (Phajus and Calanthe ). The various genera which have been 
subjected to investigation in the above-described manner will be considered 
separately. 
I. INDIGOFERA. 
Several species of this genus have been examined (loc. cit.) by Molisch, 
but the examination was — in the case of I. leptostackya ( = /. arrecta ) (13) 
and /. anil the only two species of those which he examined which yield 
indigo in any quantity — confined to dried material, and specimens of 
I. arrecta grown in the gardens at Prague. 
According to his results (5), I. Dosua, I. argentea , I. chinensis , I. decora , 
I. hirsuta , and I. galegoides yield no indigo. The absence of an indigo- 
yielding power in /. Dosua is also noted by Breaudat (14). 
In I. anil indigo can, according to Molisch, be precipitated in the 
leaves, especially in the mesophyll and epidermis, but not in the roots, 
stems, fruits, or seeds. 
In /. arrecta he finds indigo precipitated as in I. anil, but on further 
examination of fresh material (7) this statement is amplified. He finds, by 
employing the ‘ alcohol-test ’ above described, the greatest amount of 
precipitation to have taken place in and on the chloroplasts of the chloro- 
phyll bearing parenchyma of leaf-lamina. Very little occurs in the 
epidermal cells, with the exception of the epidermal hairs, in which larger 
amounts occur. 
The following species have been examined recently after treatment 
with the Sulphuric-Acetic-Persulphate reagent : — 
/. Dosua , Wall. Cat. I. anil, L. 
/. galegoides , D.C. /. sumatrana , Gaert. 
I. oligosperma , D.C. /. arrecta , Hochst. 
I. Dosua , Wall. Cat., growing in the Botanical Gardens, Cambridge, 
showed no trace of indigo. 
I. galegoides, D.C. Material obtained from this plant growing in the 
Royal Botanic Garden, Calcutta, showed no trace of indigo after treatment. 
/. oligosperma , D.C. Material from this plant was also obtained in the 
Royal Botanic Garden, Calcutta. The leaf only has been examined, and, 
when the chlorophyll had been removed by alcohol, appeared a distinct, 
though faint, blue colour. Microscopic examination of sections showed 
the distribution of indigo to be essentially the same as in I. arrecta 
described below. 
